Non-invasive profiling of antigen-specific endometrial T cells via Menstrual Effluent 2249626

Abstract Introduction While human T cell responses are well-characterized in peripheral blood, little is known about their role in the female reproductive tract, largely due to the need for invasive sampling. In this work, we leverage menstrual effluent (ME) to establish the first comprehensive profiling of antigen-specific T cell responses in the endometrium. Methods Paired samples of peripheral blood and menstrual effluent (ME) were collected from healthy donors, with ME obtained using menstrual cups (DivaCups). Samples were analyzed using high-parameter spectral flow cytometry following stimulation with peptide megapools from pathogens relevant to women’s health, including cytomegalovirus (CMV), Epstein-Barr virus (EBV), and human papillomavirus (HPV), enabling assessment of T cell responses independent of donor HLA type. Beyond quantifying their frequency, we comprehensively characterized these T cells by assessing activation markers (OX40, CD40L, CD69, CD137, CD25), memory and Treg phenotype (CCR7, CD45RA, Foxp3), tissue-residency markers (CD69, CD103, CD49a, CXCR6), cytokine (IFN‑γ, TNF‑α, IL-4, IL-17a) and cytotoxic molecules production (CD107a, Granzyme A, Granzyme B, Perforin). Results We successfully identified antigen-specific T cells in ME for the pathogens mentioned above, representing, to our knowledge, the first detection of HPV- and EBV-specific T cells in menstrual effluent. Our results revealed high inter-donor heterogeneity and pronounced differences compared with paired peripheral blood. Conclusion These findings establish menstrual effluent as a non-invasive tool for monitoring endometrial immunity and underscore its potential applications in gynecologic health. Funding Source The Tullie and Rickey Families SPARK Awards for Innovations in Immunology at La Jolla Institute. Topic Categories Mucosal and Regional Immunology (MUC)