Distinct populations of antigen specific tissue resident CD8 T cells in human cervix mucosa

Abstract

The ectocervix is part of the lower female reproductive tract (FRT), which is susceptible to sexually transmitted infections (STI). Comprehensive knowledge of the phenotypes and T cell receptor (TCR) repertoire of tissue resident memory T cells (TRM) in human FRT is lacking. We have taken single-cell RNA sequencing approaches to simultaneously define gene expression and TCR clonotypes of the human ectocervix. There are significantly more CD8 than CD4 T cells. Unsupervised clustering and trajectory analysis identify distinct populations of CD8 T cells with IFNGhiGZMBlowCD69hiCD103low or IFNGlowGZMBhiCD69medCD103hi phenotypes. Little overlap was seen between their TCR repertoires. Immunofluorescent staining shows that CD103+ CD8 TRM cells preferentially localize in epithelium while CD69+ CD8 TRM distribute evenly in epithelium and stroma. Ex vivo assays indicate up to 14% of cervical CD8 TRM clonotypes are HSV-2 reactive in HSV-2-seropositive persons, reflecting physiologically relevant localization. Our studies identify subgroups of CD8 TRM in the human ectocervix that exhibit distinct expression of antiviral defense and tissue residency markers, anatomic locations, and TCR repertoires that target anatomically relevant viral antigens. Optimization of the location, number, and function of FRT TRM is an important approach for improving host defenses to STI.