Human endometrial MAIT cells are transiently tissue resident and respond toNeisseria gonorrhoeae

Mucosa-associated invariant T (MAIT) cells are non-classical T cells important in the mucosal defense against microbes. Despite an increasing interest in the immunobiology of the endometrial mucosa, little is known regarding human MAIT cells in this compartment. The potential role of MAIT cells as a tissue-resident local defense against microbes in the endometrium is largely unexplored. Here, we performed a high-dimensional flow cytometry characterization of MAIT cells in endometrium from pre- and postmenopausal women, and in decidua from first-trimester pregnancies. Furthermore, we assessed MAIT cell function by stimulation withNeisseria gonorrhoeae(N. gonorrhoeae). Endometrial MAIT (eMAIT) cells represented a stable endometrial immune cell population as limited dynamic changes were observed during the menstrual cycle, post menopause, or in response to pregnancy. Furthermore, eMAIT cells exhibited an activated tissue-resident phenotype. Despite expressing CD69 and CD103, eMAIT cells were replenished over time by circulating MAIT cells, as assessed using human uterus transplantation as a model. Finally, functional experiments revealed the capability of MAIT cells to respond to the sexually transmitted and tissue-relevant pathogen,N. gonorrhoeae. In conclusion, our study provides novel insight into human MAIT cell dynamics and anti-microbial properties in the human uterus.

Automated summary

The study found that MAIT cells in the endometrium exhibit a relatively stable immune cell population under different physiological conditions, with validated antimicrobial capabilities. Additionally, MAIT cells showed an activated tissue-resident phenotype, aiding in the defense against pathogens. Moreover, experimental results demonstrated the ability of MAIT cells to respond to sexually transmitted pathogens such as Neisseria gonorrhoeae.