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.

The above experiments indicated that residual NK cells rapidly compensated for the deletion of the 1F8 ϩ NK cell subset, so we examined this depletion in the context of an MCMV infection. Fig. 7 shows the total NK cell percentage and the proportional distribution of NK cell subsets after mice were treated in vivo with mAb 1F8 (C/I/H) or 5E6 (C/I), infected with MCMV, and examined 4 d later. A substantial portion of NK1.1 ϩ cells remained after treatment with either of the Abs. mAb 5E6 eliminated the 5E6 ϩ 1F8 ϩ NK cell subset, but enriched for the 5E6 Ϫ 1F8 ϩ and Ly49G2 ϩ subsets. mAb 1F8 eliminated both the 5E6 ϩ and 1F8 ϩ cells, but enriched for the G2 ϩ cells. The fact that in vivo administration of mAb 1F8 eliminates cells staining with mAb 5E6 indicates that the loss of 1F8 reactive cells is due to their deletion and not to a masking of the 1F8 epitope with unlabeled mAb, because mAb 1F8 does not interfere with staining with mAb 5E6. Further, the enrichment in the Ly49G2 subset is another indicator that the 1F8 ϩ subset is lost and not just obscured by mAb. This figure does illustrate how different NK cell subsets compensate for the deletion of others.