PROJECT SUMMARY The goal of this project is to thoroughly define the immunoprotective role of tissue resident T cells (TRM) against viral pathogens. Underlying our proposed experiments is the idea that TRM have the ability to rapidly contain viruses within microscopic tissue microenvironments over rapid timeframes. Therefore, we focus on critical features of TRM such as gene expression profile, homeostasis, apoptosis and trafficking, before, during and at multiple time points following clearance of a mucosal virus within microscopic sites of infection. In Aim 1, we propose studying the specific role of antigen specific and non-specific tissue resident CD8+ T-cells, as well as tissue resident CD4+ T-cells, during rapid containment of virus in murine vaginal tissue microenvironments. In Aim 2, we interrogate the infection microenvironments in mice following clearance of virus with the specific goal of measuring rates of TRM apoptosis, homeostasis, intra-mucosal trafficking and activation status over time frames of weeks. These parameters will ultimately be evaluated for their relationship to waning protection following re-exposure to virus at various time intervals. In Aim 3, we employ human studies to assess kinetics of genital HSV-2 containment and cytokine response within single infection microenvironments, as well as localization of TRM at multiple time points following viral containment. These studies are designed to verify relevance of specific components of the mouse model to human immunity, and to provide data for design and validation of mathematical models, the goal of which is to identify a threshold quantity and spatial distribution of TRM necessary for rapid viral containment. The model will also help identify why TRM do not provide comprehensive protection against reactivating HSV-2.