Monoclonal Antibodies Practice Questions
20 free Monoclonal Antibodies practice questions for the Microbiology. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.
What does the 'xi' in the name of the monoclonal antibody Rituximab indicate about its structure?
- A It is a fully human antibody with no murine sequence
- B It is a chimeric antibody with human and mouse regions
- C It is a humanized antibody retaining only murine CDR regions
- D It is an entirely murine (mouse-derived) antibody
Correct answer: It is a chimeric antibody with human and mouse regions
The infix '-xi-' denotes a chimeric antibody, typically consisting of approximately 65% human and 35% mouse protein. This design helps reduce the immunogenicity compared to pure murine antibodies while maintaining high binding affinity.
Which of the following monoclonal antibodies is a TNF-alpha inhibitor used extensively in the treatment of Rheumatoid Arthritis and Crohn's disease?
- A Infliximab
- B Omalizumab
- C Trastuzumab
- D Abciximab
Correct answer: Infliximab
Infliximab is a chimeric monoclonal antibody that binds with high affinity to soluble and transmembrane forms of TNF-alpha. By neutralizing this cytokine, it inhibits the inflammatory cascade responsible for joint and bowel tissue damage.
Trastuzumab (Herceptin) is specifically indicated for patients with breast cancer that overexpresses which receptor?
- A Estrogen receptor
- B Progesterone receptor
- C HER2/neu (ErbB2)
- D EGFR (ErbB1)
Correct answer: HER2/neu (ErbB2)
Trastuzumab targets the Human Epidermal Growth Factor Receptor 2 (HER2). Blocking this receptor inhibits the proliferation of tumor cells that are 'addicted' to HER2 signaling for growth and survival.
What is the primary mechanism of action of Omalizumab in the management of severe asthma?
- A It blocks the IL-5 receptor on the surface of eosinophils
- B It binds free IgE, preventing it from attaching to mast cells
- C It inhibits the release of leukotrienes from activated neutrophils
- D It acts as an antagonist at the muscarinic M3 receptor
Correct answer: It binds free IgE, preventing it from attaching to mast cells
Omalizumab is a humanized monoclonal antibody that selectively binds to circulating IgE. This prevents IgE from attaching to the high-affinity FcεRI receptors on mast cells and basophils, thereby limiting the allergic inflammatory response.
Which monoclonal antibody targets the CD20 antigen on B-lymphocytes and is used to treat Non-Hodgkin Lymphoma?
- A Cetuximab
- B Bevacizumab
- C Rituximab
- D Denosumab
Correct answer: Rituximab
Rituximab binds to the CD20 antigen found on the surface of normal and malignant B-cells. This binding triggers cell death through complement-dependent cytotoxicity (CDC) and antibody-dependent cell-mediated cytotoxicity (ADCC).
Bevacizumab exerts its anti-tumor effect by inhibiting which process?
- A DNA replication
- B Angiogenesis
- C Protein synthesis
- D Microtubule assembly
Correct answer: Angiogenesis
Bevacizumab is an anti-angiogenic agent that binds to Vascular Endothelial Growth Factor (VEGF). By neutralizing VEGF, it prevents the formation of new blood vessels that tumors need to grow and metastasize.
Which of the following is a potential serious side effect of Natalizumab, used in the treatment of Multiple Sclerosis?
- A Progressive Multifocal Leukoencephalopathy (PML)
- B Acute Myeloid Leukemia
- C Pulmonary Fibrosis
- D Systemic Lupus Erythematosus
Correct answer: Progressive Multifocal Leukoencephalopathy (PML)
Natalizumab blocks alpha-4 integrin, preventing lymphocytes from crossing the blood-brain barrier. However, this local immunosuppression can allow the JC virus to reactivate in the brain, leading to the potentially fatal infection PML.
Denosumab mimics the action of osteoprotegerin (OPG) by binding to which target?
- A RANKL (Receptor Activator of Nuclear Factor kappa-B Ligand)
- B Calcium-sensing receptor
- C Calcitonin receptor
- D PTH receptor
Correct answer: RANKL (Receptor Activator of Nuclear Factor kappa-B Ligand)
Denosumab binds to RANKL, preventing it from activating the RANK receptor on osteoclast precursors. This inhibits osteoclast formation and function, thereby decreasing bone resorption in conditions like osteoporosis.
Which agent is used as an 'antidote' to reverse the effects of the anticoagulant Dabigatran?
- A Andexanet alfa
- B Idarucizumab
- C Eculizumab
- D Palivizumab
Correct answer: Idarucizumab
Idarucizumab is a humanised monoclonal antibody fragment (Fab) that binds dabigatran with an affinity roughly 350 times that of thrombin, giving immediate and complete reversal of its anticoagulant effect. Andexanet alfa is the reversal agent for the factor Xa inhibitors such as apixaban and rivaroxaban, not for dabigatran. Eculizumab is used in paroxysmal nocturnal haemoglobinuria and palivizumab in RSV prophylaxis.
Adalimumab is distinguished from Infliximab primarily because Adalimumab is:
- A A purely murine antibody
- B A fully human monoclonal antibody
- C A fusion protein rather than an antibody
- D Only effective against IL-6
Correct answer: A fully human monoclonal antibody
Adalimumab ('-umab') is a fully human IgG1 monoclonal antibody produced by phage display technology. Being fully human, it generally has a lower risk of inducing neutralizing antibodies (HACA) compared to chimeric antibodies like Infliximab.
What is the specific target of Cetuximab in the treatment of colorectal and head and neck cancers?
- A HER2
- B VEGF
- C Epidermal Growth Factor Receptor (EGFR)
- D CD52
Correct answer: Epidermal Growth Factor Receptor (EGFR)
Cetuximab is a chimeric monoclonal antibody that competitively inhibits the Epidermal Growth Factor Receptor (EGFR). It blocks ligand binding and receptor dimerization, thereby inhibiting downstream signaling pathways that promote tumor growth.
Eculizumab is used in the treatment of Paroxysmal Nocturnal Hemoglobinuria (PNH) by targeting which component?
- A Complement protein C5
- B Interferon-gamma
- C Tumor Necrosis Factor
- D B-cell activating factor
Correct answer: Complement protein C5
Eculizumab binds to the C5 complement protein, preventing its cleavage into C5a and C5b. This inhibits the formation of the Membrane Attack Complex (MAC), which prevents the intravascular hemolysis characteristic of PNH.
The monoclonal antibody Palivizumab is used as prophylaxis in high-risk infants to prevent infection from which pathogen?
- A Influenza virus
- B Respiratory Syncytial Virus (RSV)
- C Cytomegalovirus (CMV)
- D Rotavirus
Correct answer: Respiratory Syncytial Virus (RSV)
Palivizumab targets the fusion (F) protein on the surface of the Respiratory Syncytial Virus. It provides passive immunity to prevent serious lower respiratory tract disease in premature infants or those with congenital heart disease.
Which of the following antibodies targets IL-17A and is used to treat plaque psoriasis?
- A Ustekinumab
- B Secukinumab
- C Tocilizumab
- D Dupilumab
Correct answer: Secukinumab
Secukinumab is a human IgG1k monoclonal antibody that binds to IL-17A. By neutralizing this cytokine, it reduces the inflammation and keratinocyte proliferation seen in psoriasis and ankylosing spondylitis.
What is the primary target of the monoclonal antibody Ipilimumab in cancer immunotherapy?
- A PD-1
- B PD-L1
- C CTLA-4
- D CD40
Correct answer: CTLA-4
Ipilimumab is a checkpoint inhibitor that blocks CTLA-4 (Cytotoxic T-Lymphocyte-Associated protein 4). Blocking this 'brake' on the immune system allows for enhanced T-cell activation and attack against cancer cells.
Tocilizumab is a monoclonal antibody that blocks the receptor for which pro-inflammatory cytokine?
- A IL-1
- B IL-2
- C IL-6
- D IL-12
Correct answer: IL-6
Tocilizumab binds to both soluble and membrane-bound IL-6 receptors. IL-6 plays a key role in the pathogenesis of rheumatoid arthritis and cytokine release syndrome (CRS), making its blockade clinically valuable.
Which mechanism describes how many monoclonal antibodies, such as Rituximab, induce the destruction of target cells via NK cells?
- A Complement-dependent cytotoxicity (CDC)
- B Antibody-dependent cell-mediated cytotoxicity (ADCC)
- C Apoptosis induction via Fas ligand
- D Direct inhibition of ATP synthesis
Correct answer: Antibody-dependent cell-mediated cytotoxicity (ADCC)
In ADCC, the Fab region of the antibody binds to the target cell, while the Fc region binds to Fc receptors (CD16) on effector cells like Natural Killer (NK) cells. This triggers the release of perforins and granzymes to lyse the target cell.
Basiliximab is used in organ transplantation to prevent acute rejection by targeting which molecule?
- A CD3 receptor on all T-cells
- B CD25 (alpha subunit of IL-2 receptor) on activated T-cells
- C CD20 on B-cells
- D CD52 on all lymphocytes
Correct answer: CD25 (alpha subunit of IL-2 receptor) on activated T-cells
Basiliximab is an IL-2 receptor antagonist. By binding to the CD25 subunit, it prevents IL-2 from stimulating the proliferation of activated T-cells, which is a critical step in the acute rejection of a transplanted organ.
The 'mab' suffix in pharmacologic nomenclature stands for:
- A Modified Antigenic Body
- B Molecular Anti-Biological
- C Monoclonal Antibody
- D Metabolic Active Biologic
Correct answer: Monoclonal Antibody
The suffix '-mab' is the international nonproprietary name (INN) identifier for all monoclonal antibodies. It distinguishes these large, complex biological molecules from small-molecule drugs.
Which monoclonal antibody is a PCSK9 inhibitor used to treat familial hypercholesterolemia?
- A Alirocumab
- B Belimumab
- C Canakinumab
- D Golimumab
Correct answer: Alirocumab
Alirocumab binds to PCSK9, preventing it from degrading LDL receptors in the liver. This results in more LDL receptors available on the surface of hepatocytes to clear LDL cholesterol from the blood.