ADHESION MOLECULE EXPRESSION AND INFILTRATING MATERNAL LEUKOCYTE PHENOTYPES DURING BLASTOCYST IMPLANTATION IN THE PIG

During the implantation period (days 14 to 30 post coitum) in Large Wh ite pigs substantial numbers of endometrial sub-epithelial leucocytes were observed from about day 18 p.c. These were predominantly MHC Clas s II+, CD45(+) and reactive for an accessory cell determinant carried by polymorphs and macrophages. Maternal lymphocytes of the CD2(+), CD4 (+), CD8(-), and a gamma delta TcR(+) subtype identified by the mAb 86 D, were also present. Few CD4(+), CD8(+), or double-positive lymphocyt es were seen. CD2(-)CD4(-)CD8(-) gamma delta TcR(+) ''Null'' cells wer e seen in stroma adjacent to endometrial glands, as were CD2(+) lympho cytes. There was no apparent upregulation of CD18, VLA-4 or CD25. E-se lectin could not be detected on endothelium within uterine tissues or on trophectoderm, nor was a ligand for L-selectin detectable. The lumi nal aspect of the uterine epithelium was strongly reactive with anti-C D15 mAb, which was specifically blocked by lacto-N-fucopentaose III, i ndicating the presence of the Lewis(X) determinant.