Transcriptional profile of brain TRM in Toxoplasma gondii infection

During chronic infection memory T cells acquire a unique phenotype and become dependent on different survival signals than those needed for memory T cells generated during an acute infection. The distinction between the role of effector and memory T cells in an environment of persistent antigen remains unclear. Here, in the context of chronic Toxoplasma gondii infection we demonstrate that a population of CD8 T cells exhibiting a tissue resident memory (TRM) phenotype persists in the brain. We show that this population is distributed throughout the brain in both parenchymal and extraparenchymal spaces. Furthermore, this population is transcriptionally distinct and exhibits a transcriptional signature consistent with the TRM observed in acute viral infections. Overall design: Differential gene expression analysis with the following specified comparisons: 1) brain CD103+ CD8 T cells to brain CD103- CD8 T cells 2) brain CD103+ CD8 T cells to spleen CD103+ CD8 T cells 3) brain CD103+ CD8 T cells to spleen CD103- CD8 T cells