REPRODUCTION IN MICE LACKING A FUNCTIONAL TYPE-1 IL-1 RECEPTOR

Growth factors and cytokines have been identified in having critical r oles at mediating maternal-fetal interactions during pregnancy, with i nterleukin-1 being a recently implicated factor. Previous experiments indicated that repeated intraperitoneal injections of the Il-1 recepto r antagonist (Il-1Ra), which inhibits binding of interleukin-1 (Il-1) to the type 1 Il-1 receptor (Il-1Rt1) blocks blastocyst implantation i n superovulated mice, To, gain a greater insight into the role of Il-1 and type 1 Il-1 receptor in implantation, we analyzed the reproductio n of mice deficient for the Il-1Rt1. Our results show that mice lackin g this receptor do not exhibit any profound alterations in their repro duction, apart from a slight reduction in mean litter size. Furthermor e, repeated intraperitoneal injections of either IL-1Ra or the monoclo nal antibody 35F5, which also blocks ligand binding to the Il-1Rt1, di d not affect embryo implantation in either wild type and Il-1 receptor deficient mice.