Bacteremia is a condition in which live bacteria enter the bloodstream, but not the cells of the body. Which form of processing would occur to stimulate a cell-mediated immune response?
A) bacterial peptide transported from cytoplasm to rER for presentation on MHC I
B) endocytosis by APC followed by presentation on MHC II
C) neutrophil phagocytosis with presentation on Fc receptor
D) cytotoxic T-cell endocytosis for presentation on CD8 receptor
E) B-cell capping for presentation on the B-cell receptor

Question

Quizplus · Accepted Answer

Bacteria in the bloodstream would likely be engulfed by antigen-presenting cells (APCs) through endocytosis. The APCs would then process the bacteria and present bacterial peptides on MHC II molecules, which would activate a cell-mediated immune response. Option A is incorrect as presentation on MHC I is involved in activating a cytotoxic T-cell response, which involves the infected cells with intracellular pathogens. Choice C is incorrect as neutrophils are not antigen-presenting cells. Choice D is incorrect as cytotoxic T-cell endocytosis for presentation on CD8 receptor is not a known mechanism to activate a cell-mediated immune response. Choice E is incorrect as B-cell capping is involved in activating a humoral immune response, not a cell-mediated immune response.

Bacteremia Is a Condition in Which Live Bacteria Enter the Bloodstream