Q.1 Which immunotechnological method is most commonly used to detect specific proteins in a patient's blood sample?
Polymerase Chain Reaction (PCR)
Enzyme‑Linked Immunosorbent Assay (ELISA)
Western blotting
Mass spectrometry
Explanation - ELISA uses antibodies attached to an enzyme to produce a measurable color change, making it the standard technique for quantifying proteins such as hormones or disease markers in serum.
Correct answer is: Enzyme‑Linked Immunosorbent Assay (ELISA)
Q.2 What is the primary advantage of using monoclonic antibodies over polyclonal antibodies in therapeutic applications?
Higher affinity for multiple antigens
Lower production cost
Consistent specificity and reduced batch‑to‑batch variation
Ability to cross the blood‑brain barrier automatically
Explanation - Monoclonal antibodies are produced from a single B‑cell clone, giving them uniform specificity, which is essential for reproducible therapeutic effects.
Correct answer is: Consistent specificity and reduced batch‑to‑batch variation
Q.3 In a lateral flow immunoassay (LFIA) strip, the colored line that appears at the test zone indicates:
Presence of a control antibody
Successful flow of sample fluid
Binding of target antigen to labeled antibodies
Degradation of the nitrocellulose membrane
Explanation - The test line contains immobilised antibodies that capture the antigen‑antibody complex, producing a visible colored line when the target is present.
Correct answer is: Binding of target antigen to labeled antibodies
Q.4 Which of the following is a key application of immunotechnology in cancer research?
Development of CRISPR gene‑editing tools
Creation of checkpoint inhibitor antibodies
Synthesis of polymeric scaffolds for tissue engineering
Design of micro‑electromechanical sensors
Explanation - Checkpoint inhibitors are monoclonal antibodies that block proteins like PD‑1/PD‑L1, reactivating T‑cells to attack cancer cells.
Correct answer is: Creation of checkpoint inhibitor antibodies
Q.5 What does the term “immuno‑biosensor” refer to?
A device that measures electrical signals generated by antibody‑antigen interactions
A vaccine that stimulates the immune system to produce antibodies
A computational model of the immune response
A type of MRI scanner for visualising immune cells
Explanation - Immuno‑biosensors convert the binding event between an antibody and its antigen into an electronic signal, enabling rapid detection of biomarkers.
Correct answer is: A device that measures electrical signals generated by antibody‑antigen interactions
Q.6 Which labeling method is commonly used in flow cytometry to quantify cell‑surface proteins?
Radioactive iodine labeling
Fluorescent‑tagged antibodies
Gold nanoparticle conjugation
Enzyme‑linked secondary antibodies
Explanation - Fluorescent dyes attached to antibodies emit light when excited by lasers in a flow cytometer, allowing precise measurement of protein expression on individual cells.
Correct answer is: Fluorescent‑tagged antibodies
Q.7 In the context of vaccine development, what is a “subunit vaccine”?
A vaccine using whole, inactivated pathogens
A vaccine delivering only a specific antigenic protein or peptide
A vaccine that incorporates live‑attenuated viruses
A vaccine administered via electroporation
Explanation - Subunit vaccines contain purified pieces of the pathogen (often proteins) that elicit an immune response without introducing the whole organism.
Correct answer is: A vaccine delivering only a specific antigenic protein or peptide
Q.8 Which immunotechnological technique is used to map the epitope recognized by an antibody?
Epitope binning with surface plasmon resonance (SPR)
Southern blotting
Northern blotting
Chromatin immunoprecipitation (ChIP)
Explanation - SPR can assess competition between antibodies for the same epitope, allowing determination of epitope specificity and affinity.
Correct answer is: Epitope binning with surface plasmon resonance (SPR)
Q.9 A key advantage of using phage display libraries in antibody engineering is:
Ability to generate antibodies without any animal immunisation
Direct visualization of antibody‑antigen binding under a microscope
Immediate clinical approval of selected antibodies
Production of antibodies that are always human‑derived
Explanation - Phage display allows the selection of antibody fragments from vast libraries in vitro, bypassing the need for animal immunisation and enabling rapid screening.
Correct answer is: Ability to generate antibodies without any animal immunisation
Q.10 Which of the following best describes the principle of a “sandwich ELISA”?
Capture antibody → antigen → detection antibody
Antigen → enzyme‑linked antibody → substrate
Antibody → enzyme → substrate → color change
Capture antigen → detection antigen → signal amplification
Explanation - In sandwich ELISA, the target antigen is bound between two antibodies: a surface‑immobilised capture antibody and a labeled detection antibody, providing high specificity.
Correct answer is: Capture antibody → antigen → detection antibody
Q.11 What is the main purpose of using adjuvants in immunogenic formulations?
To increase the stability of the antigen
To enhance the immune response to the antigen
To provide a fluorescent label for imaging
To reduce the cost of vaccine production
Explanation - Adjuvants stimulate innate immunity, helping the adaptive immune system recognize the antigen more effectively, leading to stronger and longer‑lasting immunity.
Correct answer is: To enhance the immune response to the antigen
Q.12 Which disease is currently treated with the monoclonal antibody drug “trastuzumab”?
Rheumatoid arthritis
Breast cancer (HER2‑positive)
Hepatitis C
Type 1 diabetes
Explanation - Trastuzumab binds to the HER2 receptor, inhibiting signalling pathways that drive the growth of HER2‑positive breast cancer cells.
Correct answer is: Breast cancer (HER2‑positive)
Q.13 In immunotherapy, CAR‑T cells are engineered to:
Secrete antibodies against viral infections
Express chimeric antigen receptors that recognise tumour antigens
Produce cytokines that suppress immune activity
Present antigens on MHC class II molecules
Explanation - CAR‑T cells are T‑lymphocytes modified to display synthetic receptors that bind directly to tumour‑associated antigens, enabling targeted killing of cancer cells.
Correct answer is: Express chimeric antigen receptors that recognise tumour antigens
Q.14 Which technology combines microfluidics with immunoassays to enable rapid point‑of‑care testing?
Lab‑on‑a‑chip immunoassays
CRISPR‑Cas9 genome editing
Quantum dot imaging
Optogenetic control
Explanation - Lab‑on‑a‑chip devices miniaturise immunoassays in microfluidic channels, reducing reagent volumes and assay time while maintaining sensitivity.
Correct answer is: Lab‑on‑a‑chip immunoassays
Q.15 Which of the following is a limitation of traditional animal‑derived polyclonal antibodies?
Inability to bind multiple epitopes
Batch‑to‑batch variability
Excessively high affinity
Lack of immune response
Explanation - Polyclonal antibodies are harvested from immunised animals, leading to differences in composition and affinity between production batches.
Correct answer is: Batch‑to‑batch variability
Q.16 The term “immune checkpoint” refers to:
A genetic mutation that causes autoimmunity
Molecules that regulate the magnitude of immune responses
A laboratory technique for measuring antibody titers
A type of vaccine adjuvant
Explanation - Immune checkpoints such as CTLA‑4 and PD‑1 act as brakes on T‑cell activity; blocking them can enhance anti‑tumour immunity.
Correct answer is: Molecules that regulate the magnitude of immune responses
Q.17 Which assay format is best suited for detecting low‑abundance cytokines in serum?
Direct ELISA
Sandwich ELISA
Competitive ELISA
Dot blot
Explanation - Sandwich ELISA provides higher sensitivity because the antigen is captured by two antibodies, amplifying the detection signal.
Correct answer is: Sandwich ELISA
Q.18 In the context of immunodiagnostics, what does the acronym “RIA” stand for?
Radio‑ImmunoAssay
Rapid Immuno‑Amplification
Recombinant Immunoglobulin Antibody
Real‑time Integrated Analysis
Explanation - RIA uses radioactively labelled antigens or antibodies to quantify substances; it is highly sensitive but requires special safety protocols.
Correct answer is: Radio‑ImmunoAssay
Q.19 Which of the following is an example of a therapeutic vaccine using immunotechnology?
HPV vaccine (Gardasil)
BCG vaccine for tuberculosis
Sipuleucel‑T for prostate cancer
Influenza inactivated vaccine
Explanation - Sipuleucel‑T is a personalized cellular immunotherapy that activates a patient’s own immune cells to target prostate cancer cells.
Correct answer is: Sipuleucel‑T for prostate cancer
Q.20 Which detection principle is used in Surface Plasmon Resonance (SPR) biosensors for immunological studies?
Change in electrical resistance
Variation in light angle due to refractive index shift
Emission of fluorescence from bound antibodies
Generation of acoustic waves
Explanation - SPR measures changes in the refractive index near a metal surface caused by biomolecular binding, allowing real‑time monitoring of antibody‑antigen interactions.
Correct answer is: Variation in light angle due to refractive index shift
Q.21 Which of the following statements best describes “passive immunity”?
Immunity acquired through vaccination
Immunity generated by the host’s own immune system after exposure
Immunity transferred by administration of pre‑formed antibodies
Immunity that develops only after birth
Explanation - Passive immunity involves the direct provision of antibodies (e.g., immunoglobulin therapy) and provides immediate but temporary protection.
Correct answer is: Immunity transferred by administration of pre‑formed antibodies
Q.22 What is the primary function of the Fc region of an antibody?
Binding to the antigen
Activating complement and binding to Fc receptors on immune cells
Penetrating cell membranes
Catalysing enzymatic reactions
Explanation - The Fc (fragment crystallizable) region mediates effector functions such as complement activation and interaction with immune cells, whereas the Fab region binds antigen.
Correct answer is: Activating complement and binding to Fc receptors on immune cells
Q.23 Which of the following is NOT a typical use of immunotechnology in research?
Detecting protein‑protein interactions
Sequencing whole genomes
Quantifying cytokine levels
Isolating specific cell populations via flow cytometry
Explanation - Genome sequencing relies on nucleic‑acid based methods, not immunological detection techniques.
Correct answer is: Sequencing whole genomes
Q.24 In an immunoprecipitation (IP) experiment, the purpose of the “bead” is to:
Catalyse the binding reaction
Provide a solid support to which the antibody‑antigen complex can be captured
Emit fluorescence for detection
Denature proteins for analysis
Explanation - Beads (often agarose or magnetic) are coated with protein A/G or antibodies; they allow precipitation of the target protein complex for downstream analysis.
Correct answer is: Provide a solid support to which the antibody‑antigen complex can be captured
Q.25 Which immunotherapy strategy utilizes checkpoint blockade to treat melanoma?
Adoptive cell transfer
Anti‑PD‑1 monoclonal antibodies
DNA vaccination
Interferon‑α therapy
Explanation - Anti‑PD‑1 antibodies (e.g., pembrolizumab) block the PD‑1 pathway, restoring T‑cell activity against melanoma cells.
Correct answer is: Anti‑PD‑1 monoclonal antibodies
Q.26 The “gold standard” for confirming the presence of a specific pathogen in a clinical sample is:
Rapid antigen test
Culture followed by immunofluorescence
Polymerase Chain Reaction (PCR)
Serological ELISA
Explanation - While PCR is fast, culturing the organism and detecting it with immunofluorescence provides definitive evidence of viable pathogen presence.
Correct answer is: Culture followed by immunofluorescence
Q.27 Which of the following best explains why nanobodies (single‑domain antibodies) are advantageous for imaging applications?
They are larger than conventional antibodies, enhancing signal strength
They have high thermal stability and can penetrate tissues more easily
They can only bind to carbohydrate antigens
They are fluorescent without any conjugation
Explanation - Nanobodies are small (~15 kDa), highly stable, and can reach epitopes inaccessible to larger antibodies, making them ideal for in vivo imaging.
Correct answer is: They have high thermal stability and can penetrate tissues more easily
Q.28 What is the main purpose of using a “blocking buffer” in an ELISA plate preparation?
To increase the reaction speed
To prevent non‑specific binding of detection antibodies
To denature the antigen
To change the pH of the assay
Explanation - Blocking buffers (e.g., BSA, skim milk) occupy empty binding sites on the plate, reducing background noise from non‑specific interactions.
Correct answer is: To prevent non‑specific binding of detection antibodies
Q.29 Which of the following diseases is a target for immunotherapy using anti‑CD20 monoclonal antibodies?
Chronic lymphocytic leukemia (CLL)
Alzheimer’s disease
Type 2 diabetes
Hypertension
Explanation - Anti‑CD20 antibodies such as rituximab target B‑cell malignancies, including CLL and non‑Hodgkin lymphoma.
Correct answer is: Chronic lymphocytic leukemia (CLL)
Q.30 In the context of immunological assays, the term “signal‑to‑noise ratio” refers to:
The ratio of antigen concentration to antibody concentration
The intensity of the specific detection signal compared with background noise
The proportion of positive samples in a test batch
The speed of the assay reaction
Explanation - A high signal‑to‑noise ratio indicates a clear, reliable assay result, whereas low ratio suggests possible false‑positives or poor sensitivity.
Correct answer is: The intensity of the specific detection signal compared with background noise
Q.31 Which method is used to generate humanized antibodies from murine (mouse) antibodies?
Hybridoma fusion
CRISPR‑Cas9 gene editing of B‑cells
CDR grafting onto a human antibody framework
Protein A chromatography
Explanation - Complementarity‑determining regions (CDRs) from mouse antibodies are transplanted into human IgG frameworks, reducing immunogenicity while retaining specificity.
Correct answer is: CDR grafting onto a human antibody framework
Q.32 What is the clinical relevance of measuring anti‑double‑stranded DNA (anti‑dsDNA) antibodies?
Diagnosis of systemic lupus erythematosus (SLE)
Monitoring of hepatitis B infection
Screening for allergic rhinitis
Assessing vitamin D deficiency
Explanation - Anti‑dsDNA antibodies are highly specific for SLE and are used both for diagnosis and disease activity monitoring.
Correct answer is: Diagnosis of systemic lupus erythematosus (SLE)
Q.33 Which technology integrates antibodies with electronic transducers to detect biomarkers in real time?
Electrochemical immunosensor
Magnetic resonance imaging (MRI)
Flow cytometry
Western blotting
Explanation - Electrochemical immunosensors convert antigen‑antibody binding events into measurable electrical currents or potentials.
Correct answer is: Electrochemical immunosensor
Q.34 In the production of recombinant antibodies, which host cell line is most commonly used?
E. coli
Saccharomyces cerevisiae
CHO (Chinese hamster ovary) cells
HeLa cells
Explanation - CHO cells provide proper folding, post‑translational modifications, and high‑yield production of functional antibodies for therapeutic use.
Correct answer is: CHO (Chinese hamster ovary) cells
Q.35 Which immunological assay is based on the competition between a labeled antigen and the sample antigen for a limited number of antibody binding sites?
Sandwich ELISA
Direct ELISA
Competitive ELISA
Capture ELISA
Explanation - In competitive ELISA, the amount of labeled antigen that binds is inversely proportional to the concentration of antigen in the sample.
Correct answer is: Competitive ELISA
Q.36 Which of the following best describes the role of “adoptive cell transfer” in cancer immunotherapy?
Injection of cytokines to boost immunity
Transfusion of donor blood containing antibodies
Infusion of ex‑vivo expanded, tumour‑specific T cells
Administration of checkpoint‑inhibitor drugs
Explanation - Adoptive cell transfer involves harvesting, engineering or expanding patient’s T cells that recognize tumour antigens and reinfusing them to attack cancer.
Correct answer is: Infusion of ex‑vivo expanded, tumour‑specific T cells
Q.37 What is the main advantage of using a multiplex immunoassay platform (e.g., Luminex) over a traditional ELISA?
It can detect multiple analytes simultaneously from a single small sample volume
It eliminates the need for antibodies
It provides real‑time imaging of cells
It requires no instrumentation
Explanation - Multiplex platforms use colour‑coded beads each coupled to a different antibody, enabling simultaneous quantification of many targets.
Correct answer is: It can detect multiple analytes simultaneously from a single small sample volume
Q.38 Which immunological technique is used to map the distribution of specific proteins within tissue sections?
Immunohistochemistry (IHC)
Southern blot
Gel electrophoresis
PCR
Explanation - IHC employs antibodies conjugated to enzymes or fluorophores to visualize protein localization in thin tissue slices under a microscope.
Correct answer is: Immunohistochemistry (IHC)
Q.39 In the context of vaccine adjuvants, what does the term “TLR agonist” refer to?
A molecule that blocks T‑cell receptors
A compound that stimulates Toll‑like receptors, enhancing innate immunity
A synthetic peptide that mimics viral DNA
An enzyme that degrades antigens
Explanation - TLR agonists activate pattern‑recognition receptors, leading to cytokine production and improved adaptive immune responses to the vaccine antigen.
Correct answer is: A compound that stimulates Toll‑like receptors, enhancing innate immunity
Q.40 Which of the following is a major safety concern when using monoclonal antibodies for therapy?
Development of resistance due to viral integration
Cytokine release syndrome
Inability to cross the cell membrane
Rapid degradation by gastric acid
Explanation - Infusion of certain therapeutic antibodies can trigger massive cytokine release, causing fever, hypotension, and in severe cases, organ failure.
Correct answer is: Cytokine release syndrome
Q.41 Which technique can be employed to generate a library of antibody fragments displayed on the surface of yeast cells?
Yeast surface display
Phage display
Bacterial two‑hybrid system
Ribozyme selection
Explanation - Yeast surface display presents antibody fragments on the cell wall, allowing flow‑cytometry‑based selection of high‑affinity binders.
Correct answer is: Yeast surface display
Q.42 Which type of antibody is most commonly used as a therapeutic agent because of its long serum half‑life?
IgM
IgA
IgG
IgE
Explanation - IgG antibodies have a half‑life of about 21 days, mediated by neonatal Fc receptor recycling, making them suitable for therapeutic use.
Correct answer is: IgG
Q.43 What does the term “epitope spreading” describe in autoimmune disease progression?
The increase in antibody affinity over time
The phenomenon where the immune response expands to target additional epitopes on the same or different antigens
The migration of immune cells to distant tissues
The reduction of antigen presentation by dendritic cells
Explanation - Epitope spreading can exacerbate autoimmune conditions as new self‑reactive epitopes become recognized by the immune system.
Correct answer is: The phenomenon where the immune response expands to target additional epitopes on the same or different antigens
Q.44 Which of the following is an example of a diagnostic immunoassay that uses a fluorescent label?
Radioimmunoassay (RIA)
Fluorescence‑based lateral flow assay
Colorimetric ELISA
Agar diffusion assay
Explanation - Fluorescence lateral flow assays (FLFAs) replace colored particles with fluorescent nanoparticles, providing higher sensitivity and quantitative read‑out.
Correct answer is: Fluorescence‑based lateral flow assay
Q.45 In a “sandwich” immunoassay, why is it advantageous to use two antibodies recognizing different epitopes of the same antigen?
It reduces assay cost
It minimizes cross‑reactivity with other proteins
It ensures that the antigen is captured and detected with high specificity
It allows the assay to work without a substrate
Explanation - Dual‑epitope recognition greatly improves specificity and reduces false positives because both antibodies must bind the same target molecule.
Correct answer is: It ensures that the antigen is captured and detected with high specificity
Q.46 Which of the following statements about “bispecific antibodies” is correct?
They bind two different antigens or two different epitopes simultaneously
They are derived solely from camelid antibodies
They are always smaller than 50 kDa
They cannot be produced recombinantly
Explanation - Bispecific antibodies are engineered to simultaneously engage two distinct targets, for example linking a tumour antigen to a T‑cell receptor.
Correct answer is: They bind two different antigens or two different epitopes simultaneously
Q.47 Which assay would you choose to quantify the concentration of a hormone present at picomolar levels in serum?
Standard colorimetric ELISA
Competitive ELISA
Radioimmunoassay (RIA)
Dot blot
Explanation - RIA offers extremely high sensitivity (down to femtomolar) due to the use of radioactive labels, making it suitable for low‑abundance hormones.
Correct answer is: Radioimmunoassay (RIA)
Q.48 In immunotherapy, the term “immune checkpoint inhibitor” primarily refers to antibodies that block:
MHC class I molecules
B‑cell receptor signaling
CTLA‑4 or PD‑1/PD‑L1 pathways
Complement cascade
Explanation - Blocking CTLA‑4 or PD‑1/PD‑L1 lifts inhibitory signals on T cells, enhancing anti‑tumour immune responses.
Correct answer is: CTLA‑4 or PD‑1/PD‑L1 pathways
Q.49 Which of the following is a key feature of “engineered antibody‑drug conjugates” (ADCs)?
They consist of an antibody linked to a radioactive isotope only
They deliver a cytotoxic payload directly to antigen‑expressing cells
They are used solely for diagnostic imaging
They are always derived from mouse antibodies
Explanation - ADCs combine the specificity of antibodies with potent drugs, allowing targeted killing of cancer cells while sparing normal tissue.
Correct answer is: They deliver a cytotoxic payload directly to antigen‑expressing cells
Q.50 Which technology is commonly used to amplify weak signals in electrochemical immunosensors?
Enzyme‑linked amplification
Polymerase Chain Reaction (PCR)
Magnetic resonance imaging (MRI)
Laser‑induced fluorescence
Explanation - Enzyme labels (e.g., HRP) catalyse redox reactions that generate amplified electrical currents proportional to the amount of bound antigen.
Correct answer is: Enzyme‑linked amplification
Q.51 Which immunological assay is specifically designed to assess the functional activity of antibodies rather than just their presence?
Neutralisation assay
ELISA
Western blot
Immunoprecipitation
Explanation - Neutralisation assays test whether antibodies can block pathogen infection of cells, providing functional information beyond binding.
Correct answer is: Neutralisation assay
Q.52 What is the primary purpose of using “Protein A/G” in antibody purification?
To cleave antibodies into Fab fragments
To bind the Fc region of IgG, allowing selective capture from mixtures
To label antibodies with fluorescent dyes
To increase the antibody’s affinity for antigen
Explanation - Protein A/G immobilised on a column binds the Fc portion of IgG, enabling efficient purification of antibodies from culture supernatants.
Correct answer is: To bind the Fc region of IgG, allowing selective capture from mixtures
Q.53 Which of the following statements about “immune tolerance” is true?
It refers to the immune system’s ability to respond aggressively to all antigens
It is the state where the immune system does not react against self‑antigens
It can be induced by high‑dose antigen exposure only
It is unrelated to autoimmunity
Explanation - Immune tolerance prevents autoimmunity by eliminating or inactivating self‑reactive lymphocytes.
Correct answer is: It is the state where the immune system does not react against self‑antigens
Q.54 In the context of immunotherapy for infectious diseases, passive immunisation involves:
Vaccination with a live‑attenuated pathogen
Administration of pre‑formed antibodies to provide immediate protection
Stimulation of the patient’s own B cells with adjuvants
Genetic editing of T‑cells
Explanation - Passive immunisation (e.g., rabies immunoglobulin) supplies antibodies directly, giving short‑term immunity without requiring an immune response.
Correct answer is: Administration of pre‑formed antibodies to provide immediate protection
Q.55 Which of the following biomarkers is commonly measured by immunoassay to monitor HIV infection progression?
p24 antigen
Hemoglobin A1c
Prostate‑specific antigen (PSA)
C‑reactive protein (CRP)
Explanation - The p24 capsid protein appears early in HIV infection and can be detected by immunoassays, aiding in diagnosis and monitoring.
Correct answer is: p24 antigen
Q.56 What is the purpose of “affinity maturation” in antibody engineering?
To increase the size of the antibody molecule
To improve the binding strength of an antibody to its antigen through iterative mutation and selection
To convert IgM antibodies into IgG
To tag antibodies with fluorescent dyes
Explanation - Affinity maturation mimics somatic hypermutation, producing antibodies with higher affinity for the target.
Correct answer is: To improve the binding strength of an antibody to its antigen through iterative mutation and selection
Q.57 Which immunotechnological approach is used to detect the presence of a specific pathogen’s nucleic acid in a patient sample?
ELISA
PCR‑based nucleic‑acid amplification with probe‑based detection
Western blot
Immunohistochemistry
Explanation - Although not a direct immunoassay, many diagnostic platforms combine PCR amplification with labeled probes for rapid detection of pathogen DNA/RNA.
Correct answer is: PCR‑based nucleic‑acid amplification with probe‑based detection
Q.58 Which type of immunoassay is most suitable for high‑throughput screening of thousands of serum samples for antibodies against a new virus?
ELISA in 96‑well plates
Western blot
Immunoprecipitation
Immunofluorescence microscopy
Explanation - ELISA can be automated in multi‑well plates, allowing simultaneous processing of many samples with minimal hands‑on time.
Correct answer is: ELISA in 96‑well plates
Q.59 Which immunological technique uses magnetic beads coated with antibodies to isolate specific cell types from a heterogeneous mixture?
Magnetic‑activated cell sorting (MACS)
Flow cytometry
ELISpot
Immunodiffusion
Explanation - MACS employs antibody‑coated magnetic beads to capture target cells; a magnetic field then separates them from the rest.
Correct answer is: Magnetic‑activated cell sorting (MACS)
Q.60 What is the primary advantage of using “human‑derived single‑chain variable fragment (scFv)” antibodies in diagnostic devices?
They have a longer half‑life than full‑length IgG
They can be expressed in bacterial systems and retain antigen specificity in a compact format
They are resistant to all proteases
They do not require any purification steps
Explanation - scFv consists of the variable heavy and light domains linked together; they are small, easy to produce, and suitable for incorporation into biosensors.
Correct answer is: They can be expressed in bacterial systems and retain antigen specificity in a compact format
Q.61 Which immunological assay can be used to assess the cellular immune response by measuring cytokine secretion from individual T cells?
ELISPOT assay
ELISA
Western blot
Immunoprecipitation
Explanation - ELISPOT detects cytokine release from single cells, providing a quantitative read‑out of antigen‑specific T‑cell activity.
Correct answer is: ELISPOT assay
Q.62 In the context of immunology, “cross‑reactivity” refers to:
An antibody binding to two unrelated antigens with similar epitopes
The ability of T cells to recognise multiple HLA types
The process of antibody isotype switching
The formation of immune complexes in the blood
Explanation - Cross‑reactivity can lead to false positives in diagnostics or unintended off‑target effects in therapy.
Correct answer is: An antibody binding to two unrelated antigens with similar epitopes
Q.63 Which immunological technique utilizes a fluorescent dye‑labeled secondary antibody to visualize a primary antibody bound to its target on a blot membrane?
Fluorescence‑based Western blot
ELISA
Immunoprecipitation
Radioimmunoassay
Explanation - Fluorescent secondary antibodies enable detection of protein bands on a membrane with high sensitivity and quantitative capabilities.
Correct answer is: Fluorescence‑based Western blot
Q.64 Which of the following is a common method for conjugating a drug to an antibody in an ADC?
Maleimide‑thiol chemistry
RNA interference
CRISPR editing
Electroporation
Explanation - Maleimide groups react with thiol groups on the antibody, forming stable thioether linkages for drug attachment.
Correct answer is: Maleimide‑thiol chemistry
Q.65 What is the main reason for using “humanized” rather than fully murine antibodies in clinical therapy?
Humanized antibodies have higher affinity for antigens
They reduce the risk of immunogenic reactions in patients
They are cheaper to produce
They can cross the blood‑brain barrier
Explanation - Humanized antibodies retain murine antigen‑binding regions but replace most of the molecule with human sequences, decreasing anti‑mouse immune responses.
Correct answer is: They reduce the risk of immunogenic reactions in patients
Q.66 Which of the following immunotechnologies is used to generate “synthetic” antibodies without the need for an animal immune response?
Hybridoma technology
Phage display libraries
In‑vivo immunisation
B‑cell cloning
Explanation - Phage display allows selection of antibody fragments from vast synthetic libraries in vitro, bypassing animal immunisation.
Correct answer is: Phage display libraries
Q.67 In a “competitive inhibition ELISA”, a higher concentration of antigen in the sample will result in:
Increased color development
No change in signal
Decreased color development
Fluorescence emission
Explanation - Sample antigen competes with labeled antigen for antibody binding; more sample antigen means less labeled antigen binds, reducing signal.
Correct answer is: Decreased color development
Q.68 Which immunological marker is commonly measured to assess the efficacy of a vaccine that induces a T‑cell response?
Serum IgG concentration
Interferon‑γ (IFN‑γ) release
C‑reactive protein (CRP)
Hemoglobin level
Explanation - IFN‑γ production by T cells (e.g., measured by ELISPOT or intracellular cytokine staining) indicates cellular immunity after vaccination.
Correct answer is: Interferon‑γ (IFN‑γ) release
Q.69 Which of the following is a potential drawback of using gold nanoparticles as labels in immunoassays?
Low stability in aqueous solutions
Requirement for specialized detection equipment (e.g., spectrophotometer)
Limited ability to generate a visible color change
Incompatibility with antibodies
Explanation - Gold nanoparticles provide strong optical signals but often need spectrophotometric or plasmonic detection systems, increasing assay complexity.
Correct answer is: Requirement for specialized detection equipment (e.g., spectrophotometer)
Q.70 Which of the following best describes the principle behind a “biosensor” that utilizes a field‑effect transistor (FET) for immunodetection?
Binding of antigen changes the surface charge, modulating the current through the transistor
Antigen binding produces a magnetic field that is detected by the FET
The FET emits light when the antibody binds the antigen
The transistor measures temperature changes caused by the reaction
Explanation - FET‑based immunosensors detect changes in surface potential caused by the charged biomolecular interaction, altering the transistor’s current.
Correct answer is: Binding of antigen changes the surface charge, modulating the current through the transistor
Q.71 Which immunological test is most appropriate for determining whether a patient has developed immunity after vaccination against hepatitis B?
Detection of anti‑HBsAg IgG antibodies by ELISA
Measurement of liver enzymes (ALT, AST)
PCR for HBV DNA
Western blot for core antigen
Explanation - Presence of antibodies against hepatitis B surface antigen (HBsAg) indicates protective immunity post‑vaccination.
Correct answer is: Detection of anti‑HBsAg IgG antibodies by ELISA
Q.72 What does the term “immunogenicity” refer to in the development of therapeutic proteins?
The ability of a protein to bind to its target receptor
The propensity of a therapeutic protein to provoke an immune response in the patient
The rate at which the protein is degraded in the bloodstream
The solubility of the protein in aqueous solutions
Explanation - Immunogenicity can lead to anti‑drug antibodies that reduce efficacy or cause adverse effects.
Correct answer is: The propensity of a therapeutic protein to provoke an immune response in the patient
Q.73 Which of the following is a characteristic of a “polyvalent” vaccine?
It contains antigens from multiple strains or serotypes of a pathogen
It requires only a single dose for lifelong immunity
It is made exclusively from live‑attenuated viruses
It elicits only a cellular immune response
Explanation - Polyvalent (or multivalent) vaccines protect against several variants of a pathogen in one formulation (e.g., the quadrivalent HPV vaccine).
Correct answer is: It contains antigens from multiple strains or serotypes of a pathogen
Q.74 Which assay format is most suitable for detecting an antigen that is present in very low concentrations (femtomolar) in a complex biological matrix?
Sandwich ELISA with signal amplification
Direct ELISA
Agar diffusion test
Hemagglutination assay
Explanation - Combining the sandwich format with enzymatic or nanomaterial amplification boosts sensitivity enough for femtomolar detection.
Correct answer is: Sandwich ELISA with signal amplification
Q.75 Which of the following is the most common method for confirming the specificity of a newly generated monoclonal antibody?
Surface plasmon resonance (SPR) binding analysis
DNA sequencing of the antibody gene
Measuring the antibody’s isoelectric point
Running a gel electrophoresis
Explanation - SPR provides kinetic data (ka, kd, KD) and can test binding against related antigens to assess specificity.
Correct answer is: Surface plasmon resonance (SPR) binding analysis
Q.76 In immunotherapy for allergic diseases, the administration of allergen‑specific IgG antibodies aims to:
Neutralise IgE and prevent mast cell activation
Increase production of IgE
Destroy allergen‑presenting dendritic cells
Stimulate T‑cell proliferation
Explanation - Allergen‑specific IgG can bind allergens, blocking their interaction with IgE and reducing allergic responses.
Correct answer is: Neutralise IgE and prevent mast cell activation
Q.77 Which of the following best describes the principle of “digital ELISA” (Simoa technology)?
It uses digital PCR to amplify antibody genes
It isolates individual enzyme‑linked immunocomplexes into femtoliter wells for single‑molecule detection
It replaces the enzyme label with a fluorescent dye
It performs ELISA on a microarray chip without any labeling
Explanation - Digital ELISA counts individual enzyme reactions, achieving attomolar sensitivity far beyond conventional ELISA.
Correct answer is: It isolates individual enzyme‑linked immunocomplexes into femtoliter wells for single‑molecule detection
Q.78 Which cytokine is most commonly measured as a marker of Th1‑type cellular immunity in vaccine trials?
Interleukin‑4 (IL‑4)
Interleukin‑10 (IL‑10)
Interferon‑γ (IFN‑γ)
Transforming growth factor‑β (TGF‑β)
Explanation - IFN‑γ production by T cells indicates a Th1 response, which is important for intracellular pathogen clearance.
Correct answer is: Interferon‑γ (IFN‑γ)
Q.79 Which of the following statements about “immune escape” in cancer is correct?
Tumour cells can down‑regulate MHC molecules to avoid T‑cell detection
Immune escape only occurs after chemotherapy
It is caused solely by mutations in the tumour DNA
It can be prevented by increasing the dosage of antibiotics
Explanation - Down‑regulation of antigen presentation machinery is a common mechanism by which cancer cells evade immune surveillance.
Correct answer is: Tumour cells can down‑regulate MHC molecules to avoid T‑cell detection
Q.80 In a typical immunofluorescence assay, why is a “counterstain” such as DAPI used?
To block non‑specific binding of the primary antibody
To visualise the nuclei, providing context for the location of the target protein
To increase the fluorescence intensity of the primary antibody
To fix the cells onto the slide
Explanation - DAPI binds DNA and emits blue fluorescence, allowing researchers to locate cells and assess subcellular localisation of the stained antigen.
Correct answer is: To visualise the nuclei, providing context for the location of the target protein
Q.81 Which of the following is a hallmark of a successful “neutralising antibody” against a virus?
It binds to a conserved epitope that blocks viral entry into host cells
It binds to any viral protein regardless of function
It enhances viral replication
It only recognises viral RNA
Explanation - Neutralising antibodies prevent infection by interfering with essential steps such as receptor binding or membrane fusion.
Correct answer is: It binds to a conserved epitope that blocks viral entry into host cells
Q.82 Which immunological technique is specifically designed to detect the presence of cell‑surface markers on individual cells in a heterogeneous suspension?
Flow cytometry
ELISA
Western blot
Immunodiffusion
Explanation - Flow cytometry uses fluorescently labelled antibodies to analyse thousands of cells per second, providing quantitative data on surface marker expression.
Correct answer is: Flow cytometry
Q.83 In the context of immunology, “class switching” refers to:
The conversion of IgM antibodies into other isotypes (IgG, IgA, IgE) while retaining antigen specificity
The mutation of antibody variable regions to increase affinity
The degradation of antibodies by proteases
The transfer of antibodies across the placenta
Explanation - Class‑switch recombination changes the constant region of the antibody heavy chain, altering its effector function without changing antigen binding.
Correct answer is: The conversion of IgM antibodies into other isotypes (IgG, IgA, IgE) while retaining antigen specificity
Q.84 Which of the following best explains why “Fc engineering” is performed on therapeutic antibodies?
To alter the antigen‑binding site for higher affinity
To modify the Fc region to enhance or reduce interactions with immune effector cells
To change the antibody’s isoelectric point
To increase the molecular weight of the antibody
Explanation - Fc engineering can improve ADCC, CDC, or prolong half‑life, tailoring the therapeutic profile of the antibody.
Correct answer is: To modify the Fc region to enhance or reduce interactions with immune effector cells
Q.85 Which assay would you use to measure the concentration of a specific IgE antibody in a patient suspected of having an allergic reaction?
Total IgE ELISA
Allergen‑specific IgE immunoCAP assay
Western blot for IgG
PCR for cytokine genes
Explanation - ImmunoCAP uses a solid phase coupled with a specific allergen to quantitatively measure patient‑specific IgE antibodies.
Correct answer is: Allergen‑specific IgE immunoCAP assay
Q.86 Which of the following immunological tools can be used to identify the exact amino‑acid sequence of an epitope recognized by a monoclonal antibody?
Peptide microarray scanning
ELISA
Flow cytometry
Northern blot
Explanation - A library of overlapping peptides is probed with the antibody; binding patterns reveal the minimal epitope sequence.
Correct answer is: Peptide microarray scanning
Q.87 What is the main purpose of adding a “signal peptide” to a recombinant antibody expressed in mammalian cells?
To increase the antibody’s affinity
To direct the antibody to the secretory pathway for extracellular secretion
To make the antibody fluorescent
To prevent degradation inside the cell
Explanation - Signal peptides target nascent proteins to the endoplasmic reticulum, enabling proper folding and secretion.
Correct answer is: To direct the antibody to the secretory pathway for extracellular secretion
Q.88 Which immunological assay is commonly employed to determine the presence of anti‑drug antibodies (ADA) in patients receiving therapeutic monoclonal antibodies?
Bridging ELISA
Western blot
Immunofluorescence microscopy
PCR
Explanation - Bridging ELISA captures patient‑generated anti‑drug antibodies using labeled therapeutic antibody fragments, detecting them via a secondary detection step.
Correct answer is: Bridging ELISA
Q.89 In the development of a point‑of‑care immunoassay, why is it important to minimise the “limit of detection” (LOD)?
To ensure the assay can detect very low concentrations of the target analyte, improving early diagnosis
To increase the assay’s shelf life
To reduce the need for a cold chain
To simplify the manufacturing process
Explanation - A low LOD allows detection of disease markers at early stages when concentrations are minimal, enabling timely intervention.
Correct answer is: To ensure the assay can detect very low concentrations of the target analyte, improving early diagnosis
Q.90 Which of the following describes the main advantage of using “microarray” platforms for antibody profiling?
They require no antibodies at all
They enable simultaneous analysis of thousands of antigen‑antibody interactions on a single slide
They provide three‑dimensional imaging of cells
They can only detect nucleic acids
Explanation - Protein microarrays print many different antigens on a surface; probing with serum or antibodies yields high‑throughput profiling.
Correct answer is: They enable simultaneous analysis of thousands of antigen‑antibody interactions on a single slide
Q.91 Which immunological technique would be most appropriate for quantifying cytokine levels in cell culture supernatants?
ELISA
Southern blot
Immunoprecipitation
Chromatin immunoprecipitation (ChIP)
Explanation - ELISA is a sensitive, quantitative assay well suited for measuring soluble proteins such as cytokines in fluids.
Correct answer is: ELISA
Q.92 What is the purpose of using a “secondary antibody” conjugated with horseradish peroxidase (HRP) in an ELISA?
To bind directly to the antigen
To amplify the detection signal by catalysing a colour‑producing reaction
To increase the pH of the reaction mixture
To denature the captured antigen
Explanation - HRP converts a substrate into a coloured product, providing an amplified, measurable signal proportional to the amount of bound antigen.
Correct answer is: To amplify the detection signal by catalysing a colour‑producing reaction
Q.93 Which of the following is a primary challenge when using antibody‑based diagnostics in resource‑limited settings?
Excessively rapid assay turnaround time
Requirement for cold chain storage to maintain antibody stability
Over‑sensitivity leading to false negatives
Incompatibility with blood samples
Explanation - Many antibodies lose activity at high temperatures, making refrigeration a logistical challenge in low‑resource environments.
Correct answer is: Requirement for cold chain storage to maintain antibody stability
Q.94 In the context of immunotherapy for autoimmune disease, the administration of which type of biologic is designed to block inflammatory cytokines?
Anti‑TNFα monoclonal antibody
Anti‑CD20 antibody
Checkpoint inhibitor
CAR‑T cell therapy
Explanation - Anti‑TNFα antibodies (e.g., infliximab) neutralise tumor necrosis factor‑α, reducing inflammation in diseases such as rheumatoid arthritis.
Correct answer is: Anti‑TNFα monoclonal antibody
Q.95 Which of the following describes the principle behind a “biosensor” that utilizes a quartz crystal microbalance (QCM) for immunodetection?
Antigen binding changes the mass on the crystal surface, altering its resonant frequency
The crystal emits fluorescence when an antibody binds
The QCM measures changes in pH caused by the reaction
Antigen binding generates a magnetic field detected by the crystal
Explanation - QCM detects minute mass changes on its surface; when an antigen binds to immobilised antibodies, the frequency shift is measured.
Correct answer is: Antigen binding changes the mass on the crystal surface, altering its resonant frequency
Q.96 What is the main benefit of using “nanobody‑based” immunosensors over conventional antibody‑based sensors?
Nanobodies have higher immunogenicity
Nanobodies are smaller, more stable, and can access hidden epitopes
Nanobodies do not require any immobilisation on sensor surfaces
Nanobodies can be directly visualised by naked eye
Explanation - Their small size (~15 kDa) and robustness allow better surface packing and penetration into dense biomolecular environments.
Correct answer is: Nanobodies are smaller, more stable, and can access hidden epitopes
Q.97 Which immunological technique is employed to measure the avidity (overall strength) of an antibody‑antigen interaction?
Surface plasmon resonance (SPR)
ELISA
PCR
Northern blot
Explanation - SPR provides kinetic parameters (association/dissociation rates) from which the overall binding strength (avidity) can be derived.
Correct answer is: Surface plasmon resonance (SPR)
Q.98 In a diagnostic test for COVID‑19, the detection of which viral component by an immunoassay indicates an active infection?
Anti‑SARS‑CoV‑2 IgG antibodies
Viral nucleocapsid protein (N‑protein)
Viral RNA measured by PCR
Memory B cells specific for spike protein
Explanation - Detecting viral antigens (e.g., N‑protein) reflects the presence of the virus itself, whereas antibodies indicate past exposure.
Correct answer is: Viral nucleocapsid protein (N‑protein)
Q.99 Which of the following is a major advantage of using a “label‑free” biosensor for immunodetection?
It eliminates the need for secondary antibodies or enzymatic substrates
It provides fluorescent read‑outs
It can only detect nucleic acids
It requires extensive sample preparation
Explanation - Label‑free platforms (e.g., SPR, QCM) directly transduce binding events, simplifying assay workflow and reducing potential interference.
Correct answer is: It eliminates the need for secondary antibodies or enzymatic substrates
Q.100 Which immunological assay would be most appropriate to confirm the presence of a specific auto‑antibody in a patient with suspected systemic lupus erythematosus (SLE)?
Anti‑dsDNA ELISA
Hemagglutination assay
Western blot for bacterial proteins
PCR for viral DNA
Explanation - Anti‑double‑stranded DNA antibodies are highly specific for SLE and are routinely measured by ELISA.
Correct answer is: Anti‑dsDNA ELISA
Q.101 What is the primary role of “Fcγ receptors” on immune cells in the context of therapeutic antibodies?
To bind the antigen‑binding (Fab) region of the antibody
To recognize the Fc region and mediate effector functions such as ADCC
To transport antibodies across the blood‑brain barrier
To degrade antibodies after they bind antigen
Explanation - Fcγ receptors on NK cells, macrophages, etc., bind the Fc portion of IgG, triggering mechanisms like antibody‑dependent cellular cytotoxicity.
Correct answer is: To recognize the Fc region and mediate effector functions such as ADCC
Q.102 Which of the following best explains why “bispecific T‑cell engagers” (BiTEs) are effective in cancer therapy?
They deliver a cytotoxic drug directly to tumour cells
They simultaneously bind CD3 on T cells and a tumour‑associated antigen, bringing the cells together to induce killing
They block immune checkpoints like PD‑1
They increase the production of regulatory T cells
Explanation - BiTEs physically link T cells to cancer cells, activating T‑cell mediated cytotoxicity without the need for antigen presentation.
Correct answer is: They simultaneously bind CD3 on T cells and a tumour‑associated antigen, bringing the cells together to induce killing
Q.103 Which of the following is a common method to increase the stability of antibodies for use in harsh diagnostic environments?
Lyophilisation (freeze‑drying)
Increasing the pH to 12
Adding excess salt to the buffer
Heating the antibody before use
Explanation - Lyophilisation removes water, stabilising antibodies for long‑term storage at ambient temperatures.
Correct answer is: Lyophilisation (freeze‑drying)
Q.104 In the context of immunotherapy, the term “neoantigen” refers to:
A self‑protein that becomes immunogenic after infection
A novel antigen arising from tumour‑specific mutations
An antigen derived from bacterial pathogens
A synthetic peptide used in vaccine adjuvants
Explanation - Neoantigens are unique to cancer cells due to somatic mutations and can be targeted by personalized immunotherapies.
Correct answer is: A novel antigen arising from tumour‑specific mutations
Q.105 Which immunological assay is best suited for detecting low‑level antibodies in a high‑throughput screening of serum samples for past infection?
Multiplex bead‑based immunoassay (e.g., Luminex)
Hemagglutination assay
Immunodiffusion
Radioimmunoassay
Explanation - Bead‑based platforms allow simultaneous detection of multiple antibodies with high sensitivity and are amenable to automation.
Correct answer is: Multiplex bead‑based immunoassay (e.g., Luminex)
Q.106 Which of the following is a primary reason for using “human FcRn‑binding” engineering in therapeutic antibodies?
To increase antigen affinity
To extend serum half‑life by recycling via the neonatal Fc receptor
To enhance complement activation
To allow the antibody to cross the cell membrane
Explanation - FcRn binding protects IgG from lysosomal degradation, recycling it back to circulation and prolonging therapeutic exposure.
Correct answer is: To extend serum half‑life by recycling via the neonatal Fc receptor
Q.107 Which immunological test can be used to identify a patient’s susceptibility to developing severe allergic reactions (anaphylaxis) before exposure to a known allergen?
Basophil activation test (BAT)
Western blot for IgG
ELISA for total serum protein
PCR for cytokine genes
Explanation - BAT measures basophil degranulation (e.g., CD63 up‑regulation) upon exposure to allergen in vitro, predicting clinical reactivity.
Correct answer is: Basophil activation test (BAT)
Q.108 Which of the following best describes the function of an “immunoadsorbent column” in therapeutic apheresis?
It removes pathogenic antibodies from a patient’s blood by specific binding
It adds additional antibodies to the bloodstream
It filters out red blood cells
It measures cytokine levels in plasma
Explanation - Immunoadsorption columns contain immobilised antigens or antibodies that capture disease‑causing immunoglobulins, reducing autoimmunity.
Correct answer is: It removes pathogenic antibodies from a patient’s blood by specific binding
Q.109 Which assay is commonly employed to evaluate the neutralising capacity of antibodies generated by a COVID‑19 vaccine?
Plaque‑reduction neutralisation test (PRNT)
ELISA for spike‑protein IgG
Western blot for nucleocapsid protein
PCR for viral RNA
Explanation - PRNT measures the ability of serum antibodies to prevent viral plaque formation in cell culture, directly assessing neutralisation.
Correct answer is: Plaque‑reduction neutralisation test (PRNT)
Q.110 Which of the following is a key consideration when designing an immunoassay for a biomarker that exists in multiple isoforms?
Select antibodies that recognise a conserved region common to all isoforms
Use a single antibody that binds only one isoform
Avoid using any antibodies and rely on nucleic‑acid detection
Measure the total protein concentration by mass spectrometry only
Explanation - Targeting a shared epitope ensures the assay detects the total biomarker regardless of isoform variation.
Correct answer is: Select antibodies that recognise a conserved region common to all isoforms
Q.111 What does the term “affinity maturation” refer to in the natural immune response?
The process by which B cells increase the strength of antibody‑antigen binding through somatic hypermutation and selection
The switching of antibody class from IgM to IgG
The degradation of low‑affinity antibodies
The migration of antibodies from the bloodstream to tissues
Explanation - During germinal centre reactions, B cells acquire mutations in their variable regions; those with higher affinity are selected for expansion.
Correct answer is: The process by which B cells increase the strength of antibody‑antigen binding through somatic hypermutation and selection
Q.112 Which immunological technique can be used to determine the presence of a specific protein on the surface of a live cell without fixing or permeabilising the cell?
Flow cytometry with fluorescently labelled antibodies
Western blot
ELISA
Immunoprecipitation
Explanation - Live‑cell staining with fluorophore‑conjugated antibodies allows detection of surface markers while preserving cell viability.
Correct answer is: Flow cytometry with fluorescently labelled antibodies
Q.113 In a diagnostic immunoassay, why is it important to include a “negative control” sample?
To calibrate the instrument’s temperature
To verify that any signal observed is due to specific antigen‑antibody interaction and not background noise
To increase the assay’s sensitivity
To speed up the reaction kinetics
Explanation - Negative controls contain no target antigen, ensuring that any observed signal reflects true binding rather than non‑specific interactions.
Correct answer is: To verify that any signal observed is due to specific antigen‑antibody interaction and not background noise
Q.114 Which of the following is a common strategy to reduce the immunogenicity of a therapeutic enzyme used in enzyme replacement therapy?
PEGylation (attachment of polyethylene glycol chains)
Increasing the enzyme’s catalytic activity
Adding a fluorescent tag
Expressing the enzyme in bacterial cells
Explanation - PEGylation masks the protein surface, decreasing recognition by the immune system and prolonging circulation time.
Correct answer is: PEGylation (attachment of polyethylene glycol chains)
Q.115 Which assay would you employ to assess whether a monoclonal antibody can trigger complement‑dependent cytotoxicity (CDC) against target cells?
CDC assay measuring cell lysis in the presence of complement
ELISA for antibody concentration
Western blot for complement proteins
PCR for complement gene expression
Explanation - A CDC assay incubates target cells with antibody and complement serum; lysis indicates functional complement activation.
Correct answer is: CDC assay measuring cell lysis in the presence of complement
Q.116 Which of the following best explains why “epitope mapping” is essential during the development of a diagnostic antibody?
It identifies the precise region of the antigen that the antibody binds, ensuring specificity and avoiding cross‑reactivity
It determines the antibody’s molecular weight
It measures the antibody’s half‑life in circulation
It assesses the antibody’s ability to cross the blood‑brain barrier
Explanation - Knowing the epitope helps avoid off‑target binding and informs assay design for accurate detection.
Correct answer is: It identifies the precise region of the antigen that the antibody binds, ensuring specificity and avoiding cross‑reactivity
Q.117 Which immunological test is most appropriate for confirming the presence of a bacterial toxin in a food sample?
ELISA specific for the toxin
PCR for bacterial DNA
Western blot for bacterial proteins
Flow cytometry of bacterial cells
Explanation - ELISA can directly detect the toxin protein, providing a rapid and quantitative assessment of contamination.
Correct answer is: ELISA specific for the toxin
Q.118 What is the primary purpose of adding a “blocking agent” such as BSA to the wells of an ELISA plate before adding the sample?
To increase antigen binding capacity
To prevent non‑specific adsorption of proteins and reduce background signal
To enhance the enzymatic activity of HRP
To change the pH of the buffer
Explanation - Blocking agents occupy vacant surface sites, minimizing unwanted binding of sample components that could generate false signals.
Correct answer is: To prevent non‑specific adsorption of proteins and reduce background signal
Q.119 Which of the following best describes a “theranostic” approach in immunotechnology?
A combined diagnostic and therapeutic strategy using antibodies that both detect and treat disease
A vaccine that also serves as a diagnostic test
A technique that simultaneously measures DNA and protein levels
A method for delivering antibiotics via antibody carriers
Explanation - Theranostics integrate targeted detection (e.g., imaging) with therapy (e.g., drug delivery) using the same molecular platform.
Correct answer is: A combined diagnostic and therapeutic strategy using antibodies that both detect and treat disease
Q.120 Which immunological assay would be most appropriate to evaluate the binding kinetics (association/dissociation rates) of a new antibody candidate to its antigen?
Surface plasmon resonance (SPR)
ELISA
Western blot
Immunoprecipitation
Explanation - SPR provides real‑time kinetic data, allowing precise measurement of on‑ and off‑rates for antibody‑antigen interactions.
Correct answer is: Surface plasmon resonance (SPR)
Q.121 Which of the following is a major advantage of using “recombinant antibody fragments” (e.g., Fab, scFv) in biosensor design?
They retain full Fc effector functions
They are smaller, enabling higher surface density and faster binding kinetics
They can be directly visualised without labeling
They are resistant to all proteases
Explanation - Fragment size reduces steric hindrance, improving sensor performance and allowing dense immobilisation on sensor surfaces.
Correct answer is: They are smaller, enabling higher surface density and faster binding kinetics
Q.122 In the development of a rapid diagnostic test for malaria, the detection of which parasite component by immunochromatography is most commonly used?
Histidine‑rich protein 2 (HRP‑2)
Mitochondrial DNA
RNA polymerase
Glucose‑6‑phosphate dehydrogenase
Explanation - HRP‑2 is abundant in Plasmodium falciparum and is the target antigen in many rapid lateral flow malaria tests.
Correct answer is: Histidine‑rich protein 2 (HRP‑2)
Q.123 Which of the following best describes the role of “adjuvant” AS04 in the HPV vaccine?
It is a toll‑like receptor agonist that enhances the immune response
It is a viral vector delivering the antigen
It is a lipid nanoparticle used for mRNA delivery
It is an antibody that neutralises the virus
Explanation - AS04 contains MPL (a TLR‑4 agonist) combined with aluminum salt, boosting the vaccine’s immunogenicity.
Correct answer is: It is a toll‑like receptor agonist that enhances the immune response