Tracking Effector and Memory NK Cells During MCMV Infection.

In C57BL/6 mice, NK cells expressing the activating receptor Ly49H proliferate robustly in response to mouse cytomegalovirus (MCMV) infection. The expansion of Ly49H(+) NK cells peaks at approximately 1 week post-infection, and is then followed by a distinct contraction phase that ultimately leaves a small but long-lived pool of MCMV-experienced Ly49H(+) NK cells that are capable of mediating enhanced memory-like responses during subsequent encounters with MCMV. Here we describe an adoptive transfer model in which the expansion, contraction, and memory cell persistence of transferred Ly49H(+) NK cells are tracked in congenic C57BL/6 hosts following MCMV infection.