Indirect CD4+ T cell protection against persistent MCMV infection by NK cells requires IFNγ

Host control of mouse cytomegalovirus (MCMV) infection of MHCII - salivary gland acinar cells is mediated by CD4 + T cells, but how they protect is unclear. Here, we show CD4 + T cells control MCMV indirectly in the salivary gland, via IFNγ engagement with uninfected, but antigen + MHCII + APC and recruitment of NK cells to infected cell foci. This immune mechanism renders direct contact of CD4 + T cells with infected cells unnecessary and may represent a host strategy to overcome viral immune evasion.