T Cell-Intrinsic Interleukin 17 Receptor A Signaling Supports the Establishment of Chronic Murine Gammaherpesvirus 68 Infection.

Abstract

Gammaherpesviruses, such as human Epstein-Barr virus (EBV) and murine gammaherpesvirus 68 (MHV68), are species-specific, ubiquitous pathogens that are associated with multiple cancers, including B cell lymphomas. These viruses have a natural tropism for B cells and usurp B cell differentiation to drive a unique and robust polyclonal germinal center response to establish a long-term latent reservoir in memory B cells. The robust polyclonal germinal center response driven by gammaherpesvirus infection increases the risk for B cell transformation. Unsurprisingly, many gammaherpesvirus cancers are derived from germinal center or post-germinal center B cells. The viral and host factors that influence the gammaherpesvirus-driven germinal center response are not clearly defined. We previously showed that host interleukin 17 receptor A (IL-17RA) signaling promotes the establishment of chronic MHV68 infection and the MHV68-driven germinal center response. In this study, we found that T cell-intrinsic IL-17RA signaling recapitulates some proviral aspects of global IL-17RA signaling during MHV68 infection. Specifically, we found that T cell-intrinsic IL-17RA signaling supports the MHV68-driven germinal center response, the establishment of latency in the spleen, and viral reactivation in the spleen and peritoneal cavity. Our study unveils an unexpected finding where the T cell-specific IL-17RA signaling supports the establishment of a latent reservoir of a B cell-tropic gammaherpesvirus. IMPORTANCE Gammaherpesviruses, such as human EBV, establish lifelong infection in >95% of adults and are associated with B cell lymphomas. Gammaherpesviruses usurp the germinal center response to establish latent infection, and the germinal center B cells are thought to be the target of viral transformation. We previously found that global expression of IL-17RA promotes the establishment of chronic MHV68 infection and the MHV68-driven germinal center response. In this study, we showed that T cell-intrinsic IL-17RA signaling is necessary to promote the MHV68-driven germinal center response by supporting CD4+ T follicular helper cell expansion. We also found that T cell-intrinsic IL-17RA signaling contributes to but is not solely responsible for the systemic proviral role of IL-17RA signaling, highlighting the multifaceted function of IL-17RA signaling during MHV68 infection.