Inability to establish ectopic endometrium in a natural killer cell-deficient murine model. Immunologic, histologic and histochemical assessment.

OBJECTIVE : To investigate what effect natural killer (NK) cells have on the implantation of heterologous endometrial scrapings. STUDY DESIGN : Anti-asialo GM1 (AA-GM1) antisera have been shown to eliminate NK cell activity in various strains of rats and mice. Either AA-GMI antibodies (+) or rabbit antiglobulin (-) was administered to beige mice (NK cell deficient) or beige control mice (not NK cell deficient of the same strain). The heterologous endometrial scrapings were prepared by scraping seven pairs of uterine horns from normal mice of the same strain. Beige aid normal mice were then injected intraperitoneally every 3 days with the heterologous endometrial scrapings and antibodies for a period of 50 days. The four experimental groups (n =10 per group) can be summarized as being beige (+), beige (-), normal (+) and normal (-). RESULTS : There was no evidence of ectopic endometrial tissue in any of the four test groups by histologic examination or by using immunohistochemical staining techniques. Histologic evidence of an impaired immune response was clearly demonstrated in the beige mice receiving AA-GM1 antibodies. CONCLUSION : Using this model, a deficiency of NK cell activity did not appear to enhance the implantation of endometrial tissue on the abdominal peritoneum of mice. (J Reprod Med 1996 ;41 :807-814)