IMMUNOHISTOCHEMICAL ANALYSIS OF BETA-1-INTEGRIN RECEPTORS DISPLAYED BY MURINE UTERINE NATURAL-KILLER-CELLS OVER THE COURSE OF SUCCESSFUL PREGNANCY

Granulated metrial gland (GMG) cells are a natural killer (NK) cell-li ke population present in large numbers in the pregnant rodent uterus. By day 8 of gestation GMG cells are large and granulated and localized to the mesometrial side of each implantation site. GMG cells appear t o be highly migratory both in vivo and in vitro; however, little is kn own regarding their functions. Using indirect fluorescence immunohisto chemistry, murine uteri and implantation sites were studied on success ive days of gestation to characterize the extracellular matrix recepto rs of the VLA-integrin family displayed by GMG cells. On days 3 and 6 of gestation, double immunostaining using the monoclonal antibody LGL- 1 was employed to recognize GMG cells because their morphology early i n pregnancy resembles that of other lymphocytes. Between days 8-15 of gestation, GMG cells can be recognized by their unique morphology. The day 3 and day 6 LGL-1(+) cells were positive for all antigens examine d; that is, beta 1 plus alpha 1, alpha 3, alpha 4, alpha 5 and alpha 6 . From days 8-15 of gestation, GMG cells were beta 1(+), alpha 4(+), a lpha 5(+) but alpha 1(-), alpha 3(-), alpha 6(-). Thus, between days 6 -8 of gestation, major changes occur in the uterine NK/GMG cell popula tion which include the loss of the surface molecules VLA alpha 1, alph a 3 and alpha 6 or the rapid expansion of NK cells not expressing thes e proteins. It is postulated that major changes in the functions of ut erine NK cells are likely to be associated with these alterations in c ell surface phenotype and that functional studies of uterine NK cells should focus upon this relatively early gestational time point.