Leukocyte emigration and migration in the vagina following mating in the rabbit

Abstract

Within 45 minutes after mating in the rabbit, numerous heterophil leukocytes adhere to the endothelium of venules in the vagina. Initial association appears to occur via small protuberances from the leukocyte which fit into small indentions in the endothelial cell. Following adherence, leukocytes flatten and pass between endothelial cells. A regular intercellular space separates the leukocyte from the endothelial cells. Leukocytes subsequently migrate through the connective tissue to the epithelium. By three hours postcoitus, the region beneath the basement lamina of the vaginal epithelium is crowded with numerous juxtaposed leukocytes. Leukocytes subsequently migrate between epithelial cells into the vaginal lumen where they actively engulf spermatozoa. Spermatozoa appear to be ingested head first. Numerous small filaments are observed in the leukocyte cytoplasm in the region adjacent to the sperm head. Degranulation of azurophyl granules follows sperm uptake. The leukocyte response can be elicited either by spermatozoa (from the epididymis) or by semen (from vasectomized bucks), but is not elicited by ovulation (with human chorionic gonadotropin). It is suggested that the response may be initiated because the vagina does not distinguish between semen, spermatozoa and bacterial infection.

Activation of Polymorphonucelar Leukocytes by Spermatozoa

“…Phagocytosis of spermatozoa in the female genital tract has been observed by several authors [4,6,7,9,16,17,201. Under the light microscope it has been demonstrated that spermatozoa are attached by their heads to microvilli of the columnar cells of animals, and that they are taken up by epithelial cells and by PMN and mononuclear cells.…”

Influence of complement depletion on sperm function in the female rabbit

“…Mammals also possess naturally occurring anti-sperm IgG in serum that does fix complement and kills spermatozoa by assembly of the membrane attack complex (Johnson, 1968 ;Hancock, 1979), but its transduction into the tract at significant levels is still questionable (McAnulty & Morton, 1978). Leucocytes and sperm phagocytosis have long been recognized as sequelae to insemination (Austin, 1957 ;Bedford, 1965), and in the rabbit leucocytes appear after insemination in the vagina (Phillips & Mahler, 1977), cervix (Tyler, 1977), and uterus (Soupart, 1970). A by-product of complement activation, the anaphylotoxin C5a, could be partly responsible for this leucocyte influx.…”

Seminal Fluid Induces Leukocyte Recruitment and Cytokine and Chemokine mRNA Expression in the Human Cervix after Coitus

“…The number of neutrophils detected both before and after intercourse were much lower than that observed in cervical scrapings after donor insemination (16,17), which was surprising considering that neutrophils comprise ∼70% of all leukocytes in the cervical mucus of nonpregnant women (32). Neutrophils are also prevalent after mating in the cervical and uterine tissues of mice, rats, rabbits, and pigs (3,(5)(6)(7). In earlier studies, neutrophils were recovered from the luminal surface 4 h after insemination (16,17); therefore, it seems plausible that neutrophil migration into the lumen was complete before the second postcoital biopsy was taken.…”

“…However, studies in several species show that seminal fluid also contains signaling molecules that interact with epithelial cells lining the female reproductive tract to trigger gene expression, leukocyte recruitment, and activation of innate and adaptive immune events in a sequence that resembles an inflammatory response (1,2). This postcoital leukocytic response has been described in mice (3,4), pigs, rabbits, sheep, and other mammals (5)(6)(7)(8), and is thought to have a fundamental role in reproduction because seminal fluid signaling proteins linked with immunity and defense are present in such diverse organisms as flies, mosquitos, crickets, honeybees, rodents, and primates (9).…”