Murine Cytomegalovirus Is Regulated by a Discrete Subset of Natural Killer Cells Reactive with Monoclonal Antibody to Ly49h

Daniels, Keith A.; Devora, Gene; Lai, Wayne C.; O'Donnell, Carey L.; Bennett, Michael; Welsh, Raymond M.

Strain Distribution of 1F8 Reactivity. The resistance of mice to MCMV is very dependent on their genetic background (7) . Balb/c mice are highly susceptible, and C57BL/6 mice are resistant. In this study we found that by day 4 after infection the Balb/c mice had Ͼ 100-fold more MCMV PFUs in their spleens than did the C57BL/6 strain. Fig. 2 shows the expression of antigens detected by mAb 1F8 (C/I/H) and 5E6 (C/I) on splenocytes of these mice, all gated on cells expressing the pan NK cell marker DX-5. NK cells from the highly sensitive Balb/c strain stained with 5E6, but did not express the Ly49H subset, as defined by 1F8 ϩ 5E6 Ϫ cells. In contrast, NK cells from C57BL/6 mice had sizable proportions of both 1F8 ϩ 5E6 ϩ and 1F8 ϩ 5E6 Ϫ populations. Thus, the expression of Ly49H (defined as 1F8 ϩ 5E6 Ϫ ) on NK cells appeared to correlate with the resistance of mice to MCMV.