Ly49H+ NK cells migrate to and protect splenic white pulp stroma from murine cytomegalovirus infection.

In this study, we show that in the absence of a protective NK cell response, murine CMV causes destruction of splenic white and red pulp pulp areas in the first few days of infection. Destruction of T zone stroma is associated with almost complete loss of dendritic cells and T cells. We provide evidence that the virus replicates in red and white pulp stroma in vivo and in vitro. Control of white pulp viral replication is associated with migration of murine CMV-specific activated NK cells to white pulp areas, where they associate directly with podoplanin-expressing T zone stromal cells. Our data explain how NK cells protect the lymphoid-rich white pulp areas from CMV, allowing protective adaptive T cell-dependent immune responses to develop, and how this mechanism might break down in immunocompromised patients.