Developmentally regulated expression of interleukin-1 beta by peri-implantation conceptuses in swine

Interleukin-1 beta (IL-1 beta) is one of the critical inflammatory cytokines involved in many physiological processes. This study investigated the temporal expression of IL-1 beta in pig conceptuses. A human IL-1 beta cDNA probe and a anti-human IL-1 beta antibody were used to examine IL-1 beta gene and protein expression in pig conceptuses on days 11, 12, 13, 14, 15, 20, 30, 45, 60, 75, 90, 105 and 112 of pregnancy using Northern, Slot and Western blot analyses. A human cell line (A375.S2) was used to determine IL-1 activity in pig conceptuses. High levels of IL-1 beta mRNA were detected in days 11, 12 and 13 conceptuses. IL-1 beta protein was also detected in conceptuses on days 11, 12, 13, and 14, but not in conceptuses recovered after day 15 of pregnancy. IL-1 beta biological activity was demonstrated in days 11 and 12 conceptus homogenates, but not in homogenates of days 112 allantochorion. Low levels of IL-1 beta mRNA were detected by Northern blot analysis in Day 15 conceptuses, endometrium and myometrium only when poly(A+) RNA was used. The production of IL-1 beta by peri-implantation pig conceptuses was temporally associated with maternal recognition of pregnancy. The results suggest that conceptus IL-1 beta may be important for conceptus development and establishment of pregnancy.