RNA Seq Profiling of Murine Salivary Glands in the Presence or Absence of Active MCMV Infection

Recent work indicates that salivary glands are able to constitutively recruit CD8+ T cells and retain them as tissue resident memory T cells (TRM), independently of local infection, inflammation or antigen. To understand the mechanisms supporting T cell recruitment to the salivary gland, we compared T cell migration to the salivary gland in mice infected or not with murine cytomegalovirus (MCMV), a herpesvirus that infects the salivary gland and promotes the accumulation of salivary gland TRM. We found that acute MCMV infection increased rapid T cell recruitment to the salivary gland, but that equal numbers of activated CD8+ 44 T cells eventually accumulated in both infected and uninfected glands. T cell recruitment to uninfected salivary glands depended on chemokines and the integrin a4. Several chemokines were expressed in the salivary glands of both infected and uninfected mice and many of these could promote the migration of MCMV-specific T cells in vitro. MCMV infection increased expression of chemokines that interact with the receptors CXCR3 and CCR5, but neither receptor was needed for T cell recruitment to the salivary gland during MCMV infection. Unexpectedly however, the chemokine receptor CXCR3 was critical for T cell accumulation in uninfected salivary glands. Together, these data suggest that CXCR3 and the integrin a4 mediate T cell recruitment to uninfected salivary glands, but that redundant mechanisms mediate T cell recruitment after MCMV infection. Overall design: Transcriptomic profiling was performed on salivary glands from three MCMV-infected and three naïve mice using total RNA-Seq