When macrophages in a tissue encounter bacteria, they release cytokines that induce an inflammatory response. These cytokines act on other immune cells, to recruit them to the site of infection and to enhance their activities. In addition, these cytokines act on the endothelial cells of the blood vessel wall to:
A) Increase their permeability, allowing fluid and proteins to leak into the tissue
B) Solidify the tight junctions to prevent the bacteria from entering the blood
C) Proliferate, allowing the blood vessel to enlarge
D) Up-regulate microbicidal mechanisms, so they can kill bacteria
E) Secrete anti-microbial peptides

Question

Quizplus · Accepted Answer

Cytokines released by macrophages during an inflammatory response act on endothelial cells of the blood vessel wall to increase their permeability. This is done in order to allow fluid and proteins to leak into the tissue, which helps with the immune response against the bacteria.

When Macrophages in a Tissue Encounter Bacteria, They Release Cytokines