ATI RN
Immune System Exam Questions Questions
Question 1 of 5
How do NK cells recognize healthy cells?
Correct Answer: B
Rationale: NK cells spare healthy cells with MHC I ; opsonization is phagocytic, editing/selection (C, D) are lymphocyte processes.
Question 2 of 5
The formation of the C3 convertase is a key step in complement activation that occurs in all three complement pathways. This enzyme cleaves C3 in blood plasma, leading to a conformational change in the C3b fragment that exposes its reactive thioester group. The activated C3b is potentially harmful to the host, if it becomes covalently attached to a host cell, rather than to the surface of a pathogen. This deleterious outcome is largely avoided by:
Correct Answer: C
Rationale: C3b hydrolyzes quickly in solution , preventing host damage; it can diffuse , attach to host cells , or bind convertase but is regulated.
Question 3 of 5
Once expressed on the surface of host cells, an MHC protein remains stably associated with its bound peptide for several days. This highly stable peptide binding behavior is important because:
Correct Answer: A
Rationale: Stable binding ensures MHC reflects intracellular proteins; instability occurs, but decoys or proteases are less relevant.
Question 4 of 5
The inflammatory response produced
Correct Answer: B
Rationale: The inflammatory response is primarily triggered by tissue injury, not specifically microbial infection or erythrocyte migration, though infection can lead to injury.
Question 5 of 5
Bacterial infections can cause a serious, potentially fatal systemic inflammatory response called
Correct Answer: C
Rationale: Septic shock is a systemic inflammatory response to bacterial infection, potentially fatal, unlike anaphylaxis (allergic), pelvic disease (local), or pneumonia (lung-specific).