TABLE 1.

In vitro CTL activity is reduced in memory mice that lack NK cells during priming^a

Mouse group	% Lysis (mean ± SD)b with:
	MHC-matched MC-38 cells		MHC-mismatched EMT6 cells, HSV infected
	HSV infected	Mock infected
NK depleted	25 ± 2.8	2 ± 1	<1
Control	46 ± 4	3 ± 1.5	1.5 ± 0.5
NK supplemented	54 ± 5.2	4 ± 1	2.5 ± 1
CD4 depleted	17 ± 2	1 ± 1	<1

^aC57BL/6 mice were either depleted of or supplemented with NK cells and primed with HSV. Groups of mice depleted of CD4 T cells and another group of unmanipulated mice served as controls. On day 45, all the mice were infected with a low dose (1 × 10⁵ PFU) of HSV-Kos. The CD8⁺ T cells from these mice were purified and incubated with MHC-matched HSV-infected or mock-infected, MHC-mismatched HSV-infected, and YAC cell targets at effector/target cell ratios of 90:1, 30:1, 10:1, and 3:1, and an in vitro CTL assay was performed.

^bLysis obtained at an effector/target cell ratio of 90:1 from five mice in each group. The data presented are from one of three experiments with similar patterns of results. The YAC cell killing was insignificant. The differences between the four groups of mice are statistically significant (P < 0.0001).