In response to an intracellular bacterial or viral infection, effector T_H1 cells, macrophages, NK cells, and CD8 cytotoxic effector cells are all recruited to the site of infection. The coordinated recruitment of all of these cell types is orchestrated by: A) The secretion of the inflammatory cytokine IFN-$\gamma$ in the tissue B) The action of TNF-$\alpha$ on the endothelial cells, leading to fluid leakage into the tissue C) The up-regulation of integrin ligands such as VLA-4 on the blood vessel endothelial cells D) The shared expression of chemokine receptors on these different cell types E) The shared expression of S1PR1 on these cells, recruiting them out of lymphoid tissues

Question

Quizplus · Accepted Answer

The coordinated recruitment of different cell types to the site of infection is mediated by the shared expression of chemokine receptors on these cells. Chemokines are chemoattractant proteins that bind to specific receptors on leukocytes, directing them to migrate towards the source of the chemokine. By expressing the same chemokine receptors, effector T cells, macrophages, NK cells, and CD8 cytotoxic effector cells can all collectively respond to the same chemokine signals and migrate to the site of infection. Therefore, choice D is the best option. The other choices may play a role in the recruitment of immune cells, but they do not explain the coordinated recruitment of different cell types.

In Response to an Intracellular Bacterial or Viral Infection, Effector γ\gammaγ

In Response to an Intracellular Bacterial or Viral Infection, Effector $\gamma$