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.

Although each of these viruses activated NK cell populations and stimulated their redistribution, it is only MCMV that has been consistently shown to be highly regulated by NK cells (12-14, 16, 17, 32) . Inoculation of mice with Ab to NK1.1 results in significantly higher titers of MCMV in the spleen and liver by 3 d after infection (15, 16) . We previously showed that depletion of any one or two NK cell subsets by inoculating mice with Abs to Ly49A, C/I, D, or G2 had no effect on MCMV synthesis, even though some of these mAb combinations reacted with Ͼ 70% of the NK cells before infection (22) . This indicates that, while viral infections induce redistributions of NK cell subsets, no subset defined by the commercially available Abs is essential for the control of MCMV infection. Therefore, we questioned whether other Ly49 molecules might be of unique significance in controlling viral infections and report below on studies with mAb 1F8, recognizing Ly49H, but cross-reacting with Ly49 C and I, molecules detected by the 5E6 mAb.