Maternal immune regulation by conceptus during early pregnancy in the bovine

Abstract

During early pregnancy in the bovine, it is necessary for the conceptus not only to block the luteal regression in order to ensure continual production of luteal progesterone but also to modify maternal immune system so as to prevent the fetus in uterus from the immune destruction. The present researches are concentrated on the immune regulation of maternal uterus, peripheral blood mononuclear leukocytes and corpus luteum which induced by interferon-tau, the primary pregnancy recognition signal in the bovine but it is not well understood for modulation of the maternal immune system by conceptus. In this review, we are not only concentrated on the advance in the immune regulation of maternal uterus and peripheral blood mononuclear leukocytes but also focus on the immune regulation by the secretions of conceptus beside interferon-tau. The secretions of conceptus beside interferon-tau include placental lactogen, pregnancy-associated proteins, prostaglandin E2, non classical MHC class I, GATA transcription factors, prolactin-related protein, Cox-2 and IL-6. Furthermore, interferon-tau may be involved in maternal systemic immune regulation through peripheral blood mononuclear leukocyte, platelets and cell-free DNA by the lymph circulation and blood circulation in the bovine.