ATI RN
Immune System Practice Questions Questions
Question 1 of 5
Given the enormous heterogeneity of antigen receptors expressed on the populations of naive B and T lymphocytes, the adaptive immune response relies on a process whereby the rare lymphocyte that binds to the antigen is first induced to proliferate, before it can perform its effector function. For B cells, there is a clever mechanism that ensures that the specificity of the antibody secreted by the plasma cell will recognize the same pathogen that initially stimulated the B cell antigen receptor and induced B cell proliferation. This mechanism is:
Correct Answer: A
Rationale: Naive B cells express a single BCR, secreting the same antibody as plasma cells ; multiple receptors , upregulation , or post-secretion proliferation don't occur.
Question 2 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 3 of 5
Cardiac output
Correct Answer: D
Rationale: Cardiac output is defined as the volume of blood pumped by the heart per minute into the systemic circulation.
Question 4 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 5 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.