Gammadelta T Cells Are Required for CD8+ T Cell Response to Vaccinia Viral Infection

Abstract

Vaccinia virus (VV) is the most studied member of the poxvirus family, is responsible for the successful elimination of smallpox worldwide, and has been developed as a vaccine vehicle for infectious diseases and cancer immunotherapy. We have previously shown that the unique potency of VV in the activation of CD8+ T cell response is dependent on efficient activation of the innate immune system through Toll-like receptor (TLR)-dependent and -independent pathways. However, it remains incompletely defined what regulate CD8+ T cell response to VV infection. In this study, we showed that {gamma}{delta}T cells play an important role in promoting CD8+ T cell response to VV infection. We found that {gamma}{delta}T cells can directly present viral antigens in the context MHC-I for CD8+ T cell activation to VV in vivo, and we further demonstrated that cell-intrinsic MyD88 signaling in {gamma}{delta}T cells is required for activation of {gamma}{delta}T cells and CD8+ T cells. These results illustrate a critical role for {gamma}{delta}T cells in the regulation of adaptive T cell response to viral infection and may shed light on the design of more effective vaccine strategies based on manipulation of {gamma}{delta}T cells. ImportanceTargeting the immune systems has powerful potentials to treat many disorders, such as some cancers and viral infections. By understanding how the immune system responds to model infections, we can better determine strategies to manipulate our immune systems. Vaccinia virus is responsible for the worldwide elimination of smallpox and produces one of the longest immune responses known in humans. We know from previous findings that NK cells are required for initial immune response and CD8+ T cells are required for the elimination of the virus. How CD8+ T cells are activated in response to Vaccinia virus is not fully understood. This manuscript found that {gamma}{delta}T cells activate CD8+ T cells in response to Vaccinia virus infection through MyD88 pathway