Intra-epithelial T lymphocytes from the cervical-vaginal mucosa of healthy women contain a majority population of CD4+cells and express high levels of the HIV-1 co-receptor CCR5.

Abstract Current HIV sexual acquisition models for women posit that cell-free virus is carried into genital tissues by antigen presenting cells in the mucosa and that virus also penetrates the mucosa through microabrasions. The potential for genital mucosal intra-epithelial lymphocytes (IELs) to act as primary targets for HIV acquisition in women has not been well-characterized due to the difficulty of isolating and characterizing these cells free of blood contamination. We developed a method to enhance recovery of IELs from the lower genital tract mucosa of women using an atraumatic cervical-vaginal lavage procedure. This procedure was effective for collecting IELs with a T cell resident memory (T¬RM) phenotype from 10 healthy women without the blood contamination that often occurs using cytobrush or vaginal biopsy methods. We detected a high frequency of mucosal CD103+ expression on the CD8+ TRM cells, confirming their identity as IEL cells. Conversely, little to no CD103 expression was detected on CD4+ TRM cells. Moreover, CD4+ cells comprised up to 80% of the T cell population collected from CVL compared to CD8+ T cells (10-20%), with greater CCR5 expression compared to T cells in the peripheral blood. These results show that our atraumatic isolation method is effective for characterizing IELs in the female genital mucosa and that the abundance of CD4+ CCR5hi TRM cells in this population may likely be a highly vulnerable target for HIV-1 sexual transmission.