Biologic medicines for infectious diseases MCQs With Answer

Introduction

This quiz collection on Biologic medicines for infectious diseases is tailored for M.Pharm students studying Biological Evaluation of Drug Therapy. It covers core concepts including monoclonal antibodies, immunoglobulin therapies, vaccine design, pharmacokinetics and immunogenicity of biologics, mechanisms of action against pathogens and toxins, and real-world examples of licensed biologics. Questions range from fundamental principles (passive vs active immunization, FcRn recycling) to advanced topics (Fc engineering, target-mediated drug disposition, escape mutants, biosimilar comparability). Use these MCQs to test understanding, prepare for exams, and stimulate deeper study of how biologic therapeutics are developed, evaluated and deployed against infectious diseases.

Q1. Which primary mechanism allows neutralizing monoclonal antibodies to prevent viral infection?

• Activation of complement leading to lysis of infected host cells
• Binding to host immune receptors to increase cytokine release
• Binding to viral surface proteins to block attachment and entry into host cells
• Enhancing antigen presentation by dendritic cells

Correct Answer: Binding to viral surface proteins to block attachment and entry into host cells

Q2. Palivizumab is a monoclonal antibody licensed for prophylaxis of which infection?

• Influenza A infection in elderly patients
• Respiratory syncytial virus (RSV) in high‑risk infants
• Clostridioides difficile recurrence in adults
• Herpes simplex virus reactivation

Correct Answer: Respiratory syncytial virus (RSV) in high‑risk infants

Q3. Bezlotoxumab prevents recurrent Clostridioides difficile infection by targeting which molecule?

• C. difficile surface flagella
• Toxin B produced by C. difficile
• C. difficile binary toxin (CDT)
• Host IL‑6 receptor

Correct Answer: Toxin B produced by C. difficile

Q4. Raxibacumab is used as a countermeasure for inhalational anthrax by binding to which bacterial component?

• Lethal factor enzymatic domain
• Protective antigen of Bacillus anthracis
• Polysaccharide capsule
• Edema factor receptor

Correct Answer: Protective antigen of Bacillus anthracis

Q5. What is the main pharmacologic contribution of intravenous immunoglobulin (IVIG) in infectious disease management?

• Direct antibiotic activity against bacteria
• Provision of pooled polyclonal IgG for passive immunity and immunomodulation
• Permanent reconstitution of B cell function
• Targeted neutralization of a single viral epitope

Correct Answer: Provision of pooled polyclonal IgG for passive immunity and immunomodulation

Q6. Which process is the principal route of elimination for therapeutic monoclonal antibodies?

• Renal glomerular filtration of intact IgG molecules
• Hepatic cytochrome P450 metabolism
• Proteolytic catabolism in endosomes and lysosomes often with target‑mediated drug disposition
• Excretion unchanged in bile

Correct Answer: Proteolytic catabolism in endosomes and lysosomes often with target‑mediated drug disposition

Q7. Which Fc modification is commonly used to enhance antibody‑dependent cellular cytotoxicity (ADCC)?

• PEGylation of the Fab region
• Afucosylation of the Fc glycan to increase FcγRIIIa affinity
• Removal of FcRn binding sites to speed clearance
• Conjugation with a toxin to form an ADC

Correct Answer: Afucosylation of the Fc glycan to increase FcγRIIIa affinity

Q8. Why do conjugate vaccines produce effective immune responses in infants against polysaccharide‑encapsulated bacteria?

• They contain live bacteria that replicate and stimulate memory B cells
• The polysaccharide antigen is linked to a protein carrier to induce a T cell–dependent response
• They depend solely on maternal antibodies transferred in utero
• They bypass B cells and directly stimulate cytotoxic T lymphocytes

Correct Answer: The polysaccharide antigen is linked to a protein carrier to induce a T cell–dependent response

Q9. How is a biosimilar defined in the context of biologic medicines for infectious diseases?

• An identical synthetic copy of the original biologic made by chemical synthesis
• A highly similar version of a licensed biologic with no clinically meaningful differences in safety, purity, and potency
• A generic small‑molecule antibiotic produced by a different manufacturer
• An unrelated biologic used off‑label for the same indication

Correct Answer: A highly similar version of a licensed biologic with no clinically meaningful differences in safety, purity, and potency

Q10. Which factor most commonly increases the immunogenicity of therapeutic protein biologics?

• Intravenous administration compared with subcutaneous administration
• High structural similarity to endogenous human proteins
• Product-related impurities, aggregates, and non‑human sequence elements
• Use of human cell expression systems exclusively

Correct Answer: Product-related impurities, aggregates, and non‑human sequence elements

Q11. Antibody‑dependent enhancement (ADE) of infection is most accurately described as:

• Neutralizing antibodies preventing viral entry into cells
• Non‑neutralizing or subneutralizing antibodies facilitating increased infection of Fc receptor–bearing cells
• Complement fixation that destroys pathogens before cell entry
• Cross‑presentation of antigen to cytotoxic T cells

Correct Answer: Non‑neutralizing or subneutralizing antibodies facilitating increased infection of Fc receptor–bearing cells

Q12. Compared with inactivated vaccines, live attenuated vaccines typically produce stronger protection because they:

• Require adjuvants to stimulate innate immunity
• Replicate transiently and elicit both humoral and cellular immune responses
• Contain higher concentrations of antigenic polysaccharides
• Are administered only via the intramuscular route

Correct Answer: Replicate transiently and elicit both humoral and cellular immune responses

Q13. What cellular receptor is primarily responsible for recycling IgG and extending the half‑life of therapeutic antibodies?

• FcγRIIb on B cells
• Neonatal Fc receptor (FcRn) in endothelial and hematopoietic cells
• Complement receptor 1 (CR1)
• Toll‑like receptor 4 (TLR4)

Correct Answer: Neonatal Fc receptor (FcRn) in endothelial and hematopoietic cells

Q14. Interferon‑alpha exerts antiviral effects primarily by:

• Directly lysing infected host cells
• Inducing interferon‑stimulated genes that inhibit multiple stages of viral replication
• Blocking cytokine production in macrophages
• Neutralizing viral particles in the circulation

Correct Answer: Inducing interferon‑stimulated genes that inhibit multiple stages of viral replication

Q15. Which statement best describes the advantage of T cell–dependent responses induced by conjugate vaccines?

• They generate only short‑lived IgM responses without memory
• They enable affinity maturation and long‑lived memory B cell formation
• They do not require any antigen processing or presentation
• They are effective only in adults and not in children

Correct Answer: They enable affinity maturation and long‑lived memory B cell formation

Q16. Monoclonal antibody therapy targeting a single viral epitope may fail due to escape mutants. Which strategy reduces the likelihood of resistance?

• Using a lower dose to minimize selective pressure
• Combining monoclonal antibodies that target non‑overlapping epitopes
• Targeting only host receptors instead of viral proteins
• Frequent switching between unrelated monoclonal antibodies

Correct Answer: Combining monoclonal antibodies that target non‑overlapping epitopes

Q17. What is the typical cold‑chain storage requirement for most licensed protein biologics and vaccines to preserve stability?

• Room temperature (20–25°C) with protection from light
• Frozen at −80°C for routine clinical use
• Refrigeration at 2–8°C, avoiding freezing unless specified
• High humidity and 30–37°C incubator conditions

Correct Answer: Refrigeration at 2–8°C, avoiding freezing unless specified

Q18. Which monoclonal antibody is approved to reduce recurrence of C. difficile infection by neutralizing toxin B?

• Palivizumab
• Raxibacumab
• Bezlotoxumab
• Infliximab

Correct Answer: Bezlotoxumab

Q19. Compared to active vaccination, passive immunization with monoclonal antibodies provides which key characteristic?

• Delayed onset of protection but long‑term memory
• Immediate protection that is typically shorter in duration
• Induction of host B cell memory and T cell priming
• Permanent sterilizing immunity after a single dose

Correct Answer: Immediate protection that is typically shorter in duration

Q20. Which human IgG subclasses are most efficient at activating complement and engaging Fcγ receptors for effector functions against pathogens?

• IgG2 and IgG4
• IgG1 and IgG3
• IgG4 only
• IgG2 only

Correct Answer: IgG1 and IgG3

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