Transcriptional profile of Tim-3+ and Tim-3- CD8+ T cells from trigeminal ganglion 8 days post HSV-1 infection

The goal of this study was to compare the transcriptional profile between different subpopulations of CD8+ T cells in the trigeminal ganglion 8 days post HSV-1 infection. Within the HSV-1 infected TG, essentially all of the CD8+ T cells are virus specific and by using a tetramer for the immunodominant epitope from glycoprotein B (gB), we can separate the CD8+ T cell response into two populations: the gB-CD8+ T cells and the Subdom-CD8+ T cells. These populations have different levels of functionality during viral latency and express different checkpoint molecules that may influence this. Past work has shown that expression of PD-1 is associated with impaired functionality in this model and we are currently investigating the role of Tim-3, as there is little overlap in expression between Tim-3 and PD-1 and Tim-3 appears to mark functional cells when assessed by flow cytometry. By sorting cells first by using tetramer to create two populations of CD8+ T cells and then further separating these populations using expression of Tim-3 and PD-1, we have isolated subpopulations to assess what genes are up and downregulated in Tim-3+ cells compared to Tim-3- cells in each population. Trigeminal ganglion from 10-12 mice infected with HSV-1 were excised at 8dpi and pooled and CD8+ T cells were FACS sorted into a total of eight populations. To obtain these eight populations, the pooled sample was split into two and the CD8+ T cells were divided using a tetramer for the immunodominant gB epitope. One sample was used to obtain the gB tetramer positive cells (gB-CD8+ T cells) and the second sample was used to obtain the gB tetramer negative cells (Subdom-CD8+ T cells). These two subpopulations were each sorted into four populations based on Tim-3 and PD-1 expression (Tim-3+PD-1+, Tim-3+PD-1-, Tim-3-PD-1+, and Tim3-PD-1-). The sort was repeated twice for a total of three replicates.