Unique characteristics of NK cells throughout the human female reproductive tract.

In this study, we have analyzed the presence and subsets of NK cells throughout the tissues of the FRT. We demonstrate that there are NK cells in the various FRT tissues and that their phenotype and regulation are largely dependent upon the FRT tissue where they reside. NK cells in the Fallopian tube, endometrium, cervix, and ectocervix expressed CD9 while blood NK cells did not. We have also found that unique subsets of NK cells are in specific locations of the FRT. The NK cells in the lower reproductive tract did not express CD94, but they did express CD16. In contrast, NK cells in the upper FRT express high amounts of CD94 and CD69, but few NK cells expressed CD16. All of these FRT NK cells were able to produce IFN-gamma upon stimulation with cytokines. Furthermore, the number of NK cells varied with the menstrual cycle in the endometrium but not in the cervix or ectocervix. These data suggest that unique characteristics of the tissues may account of specific localization of different NK cell subsets.