NK cell depletion in EM/IOE-infected mice impairs expansion of effector memory CD8⁺ T cells.

Splenocytes harvested on day 7 after IOE infection from NK^-/-EM/IOE and NK^+/+EM/IOE-mice were stimulated in vitro with IOE antigens and the frequency of antigen-specific activated/effector memory T cells were determined by flow cytometry. Naïve cells were stimulated in vitro with IOE antigens. Gating on splenocytes and T cells was shown in (A). The spleens of NK^-/-EM/IOE-mice contained lower percentages (B) and absolute number (C) of CD44⁺ CD8⁺ T cells compared to that detected in the spleens of NK^+/+EM/IOE-infected mice. No significant difference in the frequency of CD62L⁺ CD8⁺ T cells between NK^-/-EM/IOE-mice and NK^+/+EM/IOE-mice. Data are presented as the means ± SD of four mice per group from two independent experiments. ** indicates P < 0.01.