Intestinal CD103- Trm cells are first responders to secondary infection

To address both the plasticity of intestinal Trm subsets and their unique contributions to tissue and systemic immunity, we have generated mice to fate map CD103+ Trm cells after primary infection and follow their location and functionality during secondary infection. We found that the intestinal CD103– Trm subset are the primary responders to secondary infection and observed limited expansion of the CD103+ Trm subset. To understand the unique features of CD103– Trm cells that allow this population to respond more quickly to secondary infection and to understand the gene expression changes that accompany Trm reactivation, we performed RNA-sequencing on CD103+Tomato+ and CD103–Tomato– LP Trm cells. Examination of gene expression profiles of CD103+ and CD103- intestinal tissue-resident memory T cells before and after secondary infection.