Immunostimulants – classification and mechanism MCQs With Answer

Immunostimulants – classification and mechanism MCQs With Answer

Immunostimulants are agents that enhance host immune responses and are essential study topics for B. Pharm students. This concise, keyword-rich overview covers immunostimulants, classification (biologicals, synthetic, adjuvants, cytokines), mechanisms (TLR agonism, cytokine induction, macrophage and NK activation), clinical uses, and safety. Understanding molecular pathways MyD88, NF-κB, interferons, and downstream Th1/Th2 modulation helps pharmacists optimize immunotherapy, vaccine adjuvant selection, and manage adverse effects. This set of 30 MCQs focuses on pharmacology, clinical examples (levamisole, imiquimod, poly I:C, alum, CSFs), mechanisms of action, and therapeutic implications to reinforce learning and for exam preparation. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. Which of the following is classified primarily as an immunostimulant used in oncology and immunotherapy?

• Levamisole
• Prednisone
• Cyclophosphamide
• Azathioprine

Correct Answer: Levamisole

Q2. Which of the following is a biological immunostimulant (cytokine) used clinically?

• Interferon-alpha
• Levamisole (synthetic)
• Alum (adjuvant)
• Prednisone

Correct Answer: Interferon-alpha

Q3. Imiquimod acts as an immunostimulant through agonism of which toll-like receptor?

• TLR7
• TLR3
• TLR4
• TLR9

Correct Answer: TLR7

Q4. Which adjuvant classically promotes a strong Th2-biased antibody response and is widely used in human vaccines?

• Alum
• CpG oligonucleotides
• Poly I:C
• MPL (monophosphoryl lipid A)

Correct Answer: Alum

Q5. Monophosphoryl lipid A (MPL) used in some vaccine formulations primarily signals through which receptor?

• TLR4
• TLR3
• TLR7
• TLR9

Correct Answer: TLR4

Q6. Interferon-alpha exerts antiviral and immunostimulatory actions mainly by activating which intracellular pathway?

• JAK-STAT pathway leading to antiviral protein expression
• Direct inhibition of ribosomal RNA synthesis
• Blocking TLR signaling at the cell surface
• Chelation of divalent cations to prevent viral entry

Correct Answer: JAK-STAT pathway leading to antiviral protein expression

Q7. Which colony-stimulating factor is commonly used to treat chemotherapy-induced neutropenia?

• G-CSF (filgrastim)
• Erythropoietin
• Interleukin-10
• Interferon-gamma

Correct Answer: G-CSF (filgrastim)

Q8. Which cytokine is the principal activator of macrophages and drives Th1 immune responses?

• IFN-gamma
• IL-4
• IL-10
• TGF-beta

Correct Answer: IFN-gamma

Q9. Poly I:C is a synthetic analog of viral double-stranded RNA that primarily activates which pattern recognition receptor?

• TLR3
• TLR7
• TLR4
• TLR9

Correct Answer: TLR3

Q10. Levamisole’s immunostimulatory mechanism is best described as:

• Enhancement of T-cell and macrophage function with nonspecific immune activation
• Direct inhibition of B-cell antibody production
• Suppression of neutrophil chemotaxis
• Selective blockade of IL-2 receptors

Correct Answer: Enhancement of T-cell and macrophage function with nonspecific immune activation

Q11. Which of the following is a TLR9 agonist used experimentally as an immunostimulant and vaccine adjuvant?

• CpG oligonucleotides (CpG ODN)
• Imiquimod
• Poly I:C
• Alum

Correct Answer: CpG oligonucleotides (CpG ODN)

Q12. The most common acute adverse effects associated with systemic interferon therapy include:

• Flu-like symptoms and neuropsychiatric changes
• Hypertension and hyperglycemia
• Severe hypokalemia
• Profound neutropenia only

Correct Answer: Flu-like symptoms and neuropsychiatric changes

Q13. The adjuvant effect of alum is primarily mediated by which of the following mechanisms?

• Formation of an antigen depot and activation of inflammasome pathways favoring Th2 responses
• Direct activation of cytotoxic T lymphocytes via MHC I cross-presentation
• Blocking antigen degradation in lysosomes indefinitely
• Specific inhibition of IL-12 secretion

Correct Answer: Formation of an antigen depot and activation of inflammasome pathways favoring Th2 responses

Q14. Topical imiquimod is indicated clinically for which of the following conditions due to its local immune-stimulating properties?

• External genital warts and superficial basal cell carcinoma
• Systemic lupus erythematosus
• Deep fungal infections
• Chronic hepatitis C monotherapy

Correct Answer: External genital warts and superficial basal cell carcinoma

Q15. Which of the following monoclonal antibodies functions as an immune checkpoint inhibitor to enhance T-cell responses?

• Ipilimumab (anti-CTLA-4)
• Rituximab (anti-CD20)
• Trastuzumab (anti-HER2)
• Infliximab (anti-TNF-alpha)

Correct Answer: Ipilimumab (anti-CTLA-4)

Q16. Colony-stimulating factors (CSFs) primarily exert their therapeutic effect by:

• Stimulating proliferation and differentiation of myeloid progenitor cells in bone marrow
• Directly lysing circulating bacteria
• Blocking complement activation
• Inhibiting thymic T-cell maturation

Correct Answer: Stimulating proliferation and differentiation of myeloid progenitor cells in bone marrow

Q17. Aldesleukin (recombinant IL-2) is used clinically to stimulate immune responses in which malignancies?

• Metastatic melanoma and renal cell carcinoma
• Chronic lymphocytic leukemia only
• Breast cancer exclusively
• Non-melanoma skin cancers only

Correct Answer: Metastatic melanoma and renal cell carcinoma

Q18. MF59 is an example of which class of vaccine adjuvants?

• Oil-in-water emulsion adjuvant
• Aluminum salt adjuvant
• Saponin-based adjuvant
• Toll-like receptor 9 agonist

Correct Answer: Oil-in-water emulsion adjuvant

Q19. CpG oligonucleotide adjuvants (TLR9 agonists) favor Th1 responses largely by inducing which cytokine from dendritic cells?

• IL-12
• IL-4
• IL-10
• TGF-beta

Correct Answer: IL-12

Q20. Which toll-like receptor signals predominantly via the TRIF adaptor molecule rather than MyD88?

• TLR3
• TLR7
• TLR2
• TLR9

Correct Answer: TLR3

Q21. A common adverse effect experienced by patients receiving G-CSF (filgrastim) is:

• Bone pain
• Hyperpigmentation
• Pulmonary fibrosis
• Severe hypoglycemia

Correct Answer: Bone pain

Q22. Upregulation of MHC class II on antigen-presenting cells is a hallmark action of which cytokine?

• IFN-gamma
• IL-4
• IL-10
• IL-13

Correct Answer: IFN-gamma

Q23. Which of the following represents a specific immunostimulant as opposed to a nonspecific immunostimulant?

• Vaccine
• Levamisole
• G-CSF
• Imiquimod

Correct Answer: Vaccine

Q24. QS-21, a saponin-derived adjuvant, enhances immune responses primarily by:

• Promoting antigen cross-presentation and cytotoxic T-cell responses
• Neutralizing endotoxin in vaccine preparations
• Inhibiting dendritic cell maturation
• Blocking IL-2 receptor signaling

Correct Answer: Promoting antigen cross-presentation and cytotoxic T-cell responses

Q25. High-dose IL-2 therapy is associated with which potentially life-threatening adverse syndrome?

• Capillary leak syndrome
• Stevens-Johnson syndrome
• Hemolytic uremic syndrome
• Serotonin syndrome

Correct Answer: Capillary leak syndrome

Q26. Immune checkpoint inhibitors such as anti-PD-1 antibodies enhance antitumor immunity by which mechanism?

• Blocking inhibitory signals on T cells to restore cytotoxic activity
• Directly destroying tumor DNA
• Stimulating B cells to produce nonspecific antibodies
• Inhibiting antigen presentation by dendritic cells

Correct Answer: Blocking inhibitory signals on T cells to restore cytotoxic activity

Q27. Which recombinant interferon formulation is used in chronic hepatitis B and C treatment regimens?

• Peginterferon alfa-2a
• Interferon-beta-1b only for multiple sclerosis
• Interferon-gamma for tuberculosis
• Interleukin-1 receptor antagonist

Correct Answer: Peginterferon alfa-2a

Q28. Which cytokine is particularly important for NK cell development, survival, and activation and is being explored as an immunostimulant?

• IL-15
• IL-4
• IL-10
• TGF-beta

Correct Answer: IL-15

Q29. One general mechanism by which vaccine adjuvants enhance adaptive immunity is:

• Increasing antigen uptake and activation of antigen-presenting cells
• Preventing antigen recognition by B cells
• Directly killing T regulatory cells only
• Degrading antigens before presentation

Correct Answer: Increasing antigen uptake and activation of antigen-presenting cells

Q30. Use of potent systemic immunostimulants is relatively contraindicated in which clinical situation due to risk of graft rejection?

• Recent solid organ transplantation
• Stable primary immunodeficiency requiring immunoglobulin replacement
• Controlled hyperthyroidism
• Hypogammaglobulinemia on replacement therapy

Correct Answer: Recent solid organ transplantation

G S Sachin

I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.

Mail- Sachin@pharmacyfreak.com