Equine Lactoferrin Increases in vitro Binding of Polymorphonuclear Neutrophils to Spermatozoa

Following insemination, spermatozoa induce a migration of polymorphonuclear neutrophils (PMNs) to the uterine lumen, which play a major role in resolution of the post-mating inflammatory response. Equine lactoferrin is an iron binding glycoprotein (~ 80 kDa) that is present in large amounts in the seminal plasma of the stallion and in the endometrium of the mare during estrus. Lactoferrin plays an important role in modulating immune and inflammatory responses, particularly as a mediator of cell-to-cell interactions. Due to its role in host defense mechanisms and its high concentration in seminal plasma, we hypothesized that lactoferrin modulates PMN-sperm interactions in the uterus. The objectives of this study were: 1) to characterize the role of lactoferrin in the post-mating inflammatory response of the uterus and 2) to characterize the expression of lactoferrin mRNA and protein in the testis and epididymis of stallions. [...]