ATI RN
Immune System Practice Questions Questions
Question 1 of 5
Antibodies that bind with high affinity to some viral surface proteins require heavy chain CDR3 loops of unusual length. Whereas the average human heavy chain CDR3 length is ~15 amino acids, antibodies with V_H CDR3 loops of >30 amino acids are readily detected in the repertoire. These antibody heavy chains with CDR3 lengths of >30 amino acids would likely be missing in individuals lacking:
Correct Answer: D
Rationale: TdT adds nucleotides for long CDR3; RAG , DNA-PK , Artemis , and Ku are recombination essentials.
Question 2 of 5
Which of the following diseases cannot currently be prevented by vaccination?
Correct Answer: A
Rationale: As of 2012 (document date), no effective AIDS vaccine existed, unlike for polio, measles, and tetanus.
Question 3 of 5
Which of the following types of cells does HIV preferentially infect?
Correct Answer: C
Rationale: HIV infects helper T cells via CD4 receptors, disrupting immune regulation, not cytotoxic T, NK, or memory cells primarily.
Question 4 of 5
Which of the options below best completes the following statement: Perforin is a protein secreted by NK cells which.
Correct Answer: C
Rationale: Perforin forms pores in target cell membranes, allowing granzymes to enter and induce lysis, not related to C9 or MHC detection.
Question 5 of 5
Complete the following sentence. Proliferation and differentiation of B cells can be enhanced by thymus independent antigens including......
Correct Answer: D
Rationale: TLR-PAMP and C3d-CD21 interactions enhance TI antigen responses, not C5d (not a complement opsonin).