Mast cells (MCs) are important for innate and adaptive immunity and known to be involved in immune responses against bacterial infections. In contrast, little is known about their role in viral infections. Therefore, we investigate the role of MCs in the development of viral specific CD8 T cell responses using the well-characterized murine LCMV model.  Here, we showed that the activation of viral specific CD8 T cells was strongly impaired in mast cell deficient mice compared to wild type mice at the peak of infection. Both extracellular activation marker expression on CD8 T cells as well as their INF-g production were decreased in the absence of mast cells. In addition, costimulatory molecule expression on both lymphoid and myeloid dendritic cells as well as type-1 interferon production was significantly reduced in mast cell deficient mice at day 1 and 3 post infection. 
These results suggest that MCs are important for CD8 T cell activation and function during viral infections through the activation and cytokine production of dendritic cells. A better understanding of the impact of MCs on CD8 T cell responses may help to improve antiviral immunity and to modulate and ameliorate inflammatory responses during viral infections including skin viral infections.

Mast cells modulate antigen-specific CD8 T cell activation during viral infection