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

Multiple Choice

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