REPRODUCTIVE IMMUNOLOGY

Women who have unprotected sexual intercourse with the same man for > 1 year (and to a much lesser extent men with the same female partner) generate a significant peripheral alloimmune response against their partner's leucocytes compared with third-party leucocytes : this "immunisation" probably arises via repeated exposure to HLA antigens expressed on leucocytes and epithelial cells in semen and female genital secretions

Immunosuppressive effects of human seminal plasma


The presence of HLA molecules on the surface of the seminal cells and spermatozoa has been a matter of controversy, and several techniques have been used to address this issue [3, 4]. The expression of these molecules on sperm cells may play a role in the fertilization process [5]. In infertile women, a significantly higher incidence of circulating anti-HLA antibodies was found [6], and the existence of mechanisms inhibiting the fertilization of MHCcompatible gametes have been postulated in tunicates [7] and mammals [8]. Indeed, HLA heterozygosity is favored in certain human populations [9], and an excess of HLA antigen sharing has been found in couples with repetitive abortions [10]. Recent work from our group clearly showed the expression of HLA class I and class II molecules on purified sperm cells [11]. The expression seemed diploid, followed a cyclic pattern, and apparently showed an inverse correlation with inhibin concentration [11], inducing cyclic expression

Human sperm
express CD46 / membrane cofactor protein (MCP) on the inner acrosomal membrane (IAM) as a hypoglycosylated form that is not observed in other tissues. Sperm-specific abnormalities in MCP have been associated with infertility in humans. Antibodies to the first complement control protein (CCP) repeat of MCP inhibit both binding and penetration of human sperm to zona pellucida more efficiently than Abs to CCPs 2-4, which block complement regulatory activity.

Pregnancy : immunological inertia : specific depression of immunity in a mother toward the histocompatibility antigens of a fetus, or in a fetus toward those of the mother; it does not include immunologic tolerance.

Colostrum (see also physiology of mammary gland). 100 mL / day are produced for < 10 days after delivery. thin, yellow, milky fluid secreted by the mammary gland before or after parturition. It contains up to 20% protein, predominant among which are immunoglobulins, representing the antibodies found in maternal blood. It contains more minerals and less fat and carbohydrate than does milk. It also contains many colostrum corpuscles and usually will coagulate on boiling due to a large amount of lactalbumin. Colostrum collected within 24-48 hours post birth contains : Natural and caesarean births can leave substantial wounds in mothers : lactation speeds wound healing and lowers stress in rats. After a mother gives birth, her prolactin and oxytocin levels increase : prolactin boosts the number of circulating immune cells, which may speed repair, and oxytocin, which prompts lactation, lowers the levels of stress hormones.

It appears that BF may have a protective effect on childhood cancer, both the duration of BF as well as the quantity of milk ingested is probably critical to the beneficial immunological effects of BF against childhood cancer if anyref.

Cow milk : the rate of IgG1 accumulation decreased rapidly after calving; this decrease corresponded to a return to normal serum levels of this immunoglobulin. Selective accumulation of IgA > IgM > IgG1 was maintained throughout lactation, but IgG2 showed no selective accumulation beyond 5 days postpartum. In serum, IgA and IgM levels were elevated at parturition and showed a significant decrease postpartum. Increases in serum IgA levels 60 days postpartum corresponded to a rise in lacteal concentration. The concentration of all immunoglobulins increased during late lactation, coincident with a major reduction in milk yield. Six strains of mastitis-causing organisms were cultured during the period of the experiment; however, none resulted in clinical mastitis or showed an effect on immunoglobulin secretionref.

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