Collectins in regulation of feto-maternal cross-talk

Collectins, such as surfactant protein A (SP-A), surfactant protein D (SP-D) and mannose binding lectin (MBL), belong to evolutionarily conserved family of C-type lectins that are integral to innate immune system. These molecules can bind to a range of pathogens and endogenous danger-associated molecular patterns and bring about their clearance by several mechanisms such as phagocytosis via opsonization, aggregation, and complement activation (in the case of MBL). Collectins also interact with immune cell receptors, and thus, modulate immune cell properties in order to accomplish immune homeostasis. During pregnancy, collectins are expressed by gestational tissues as well as amniotic fluid indicating their relevance in feto-maternal cross-talk and pregnancy development. A number of studies have been undertaken to unravel their functional significance in implantation, placentation, pregnancy maintenance and parturition in normal and adverse pregnancies. Here, we discuss the expression profile, hormonal regulation and functional roles that have been attributed to SP-A, SP-D and MBL in pregnancy, parturition and pregnancy disorders such as spontaneous abortion, preterm birth, preeclampsia and gestational diabetes.