T-Cell Biology in the Female Reproductive Tract: Relevance to HIV Infection.

Worldwide, most HIV infections occur across a mucosal surface during sexual contact, with women accounting for nearly half of reported new HIV infections across the globe in 2024. Most new infections in women and girls are believed to involve transmission across mucosal surfaces of the lower reproductive tract, which includes the vagina and ectocervix. Nevertheless, HIV-susceptible target cells are present in both the lower and upper reproductive tract, as are antigen-specific T-cells. Advances in the field of T-cell biology over the past decades have elucidated the differentiation and trafficking of mucosal T-cells, including tissue-resident populations. In addition, recent studies incorporating advances in tissue sampling, immune cell phenotyping and multi-omics technologies have enhanced our understanding of adaptive immune responses to HIV within the reproductive tract. This review summarizes our current understanding of T-cell biology in the female reproductive tract and its relevance to HIV infection.