Immunity Fetus

Humoral antibodies of the IgG elass are able to eross the placenta flxm mother to fetus. These antibodies will provide passive proteetion of the new-born against those diseases which involve humoral immunity and to which the mother is immune. In this fashion, new-born infants in the UK have passive proteetion against tetanus but not against tuberculosis which requires cell-mediated immunity. Seeretory antibodies are also passed to the new-born together with the first deliveries of breast milk (colostrum). Such antibodies provide some passive protection against infections of the gastrointestinal tract. 

Rh incompatibility may occur when an Rh negative mother carries an Rh-positive fetus. At the time of delivery, a small amount of the baby s Rh-positive blood may gain access to the maternal circulation. In response, the immune system of the mother produces anti-Rh antibodies. During the subsequent pregnancy, the fetus is exposed to these antibodies as they cross the placenta. If this fetus is also Rh-positive, then the anti-Rh antibodies attack the fetal erythrocytes and cause hemolytic disease of the newborn (erythroblastosis fetalis). This may occur in about 3% of second Rh-positive babies and about 10% of third Rh-positive babies. The incidence continues to increase with subsequent pregnancies. 

Tetracyclines inhibit P. acnes, reduce the amount of keratin in sebaceous follicles, and have antiinflammatory properties (inhibiting chemotaxis, phagocytosis, complement activation, and cell-mediated immunity). Drawbacks to tetracyclines include hepatotoxicity and predisposition to infections (e.g., vaginal candidiasis). Other adverse effects include GI disturbances, photosensitivity, tooth discoloration in children, and inhibition of skeletal growth in the developing fetus. Tetracyclines must not be combined with systemic retinoids because of an increased risk of intracranial hypertension. / Tetracycline is the least expensive agent in this class and is often... 

Sensitivity of the immune system to Pb appears to differ across life stages, and studies in rodents suggest that the gestational and neonatal periods are the most sensitive. Compared to adults, the increased dose sensitivity of the embryo-fetus would appear to fall in the range of 3-12X depending upon the immune endpoint considered. Recent studies have suggested that exposure of embryos to Pb producing neonatal BLLs below 10 pg/dL can also produce later-life immunotoxicity (Table 12.2). Furthermore,... 

Gehrs, B.C., Smialowicz, RJ. Alterations in the developing immune system of the F344 rat after perinatal exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin. I. Effects on the fetus and the neonate, Toxicol., 122, 219, 1997... 

Passive immunity Providing temporary protection from disease through the administration of exogenously produced antibody (i.e., transplacental transmission of antibodies to the fetus or the injection of immune globulin for specific preventive purposes). 

Generally, it appears that effects of xenobiotics on organs or endpoints may be similar in children and adults, e.g., liver necrosis observed in adults will also be observed in children. As regards toxicodynamics, age-dependent differences are primarily related to the specific and unique effects that substances may have on the development of the embryo, fetus, and child in that the physiological development of the nervous, immune, and endocrine/reproductive systems continues until adolescence (12 to 18 years). Furthermore, receptors and other molecular targets for various xenobiotics are continuously developing during the embryonic, fetal, and infant periods. This may cause age-dependent differences in the outcome of receptor-xenobiotic interactions and even result in opposite effects of xenobiotics in infants and adults. The available data are insufficient to evaluate... 

IgM may be regarded as the most primitive of the immunoglobulins. It is the first antibody produced in response to an antigen in the primary immune response. In human gestation it is the first Ig to be produced in the fetus in response to infection, e.g., syphilis, malaria, toxoplasmosis, and rubella in some of the lower vertebrates it is the only immunoglobulin as yet detected. 

Pregnancy and labour are also times of altered drug responsiveness the fetus has special susceptibility to some adverse drug reactions though may be immune to others, for example due to the drug not passing the placenta. 

Rubella Immune globulin (IM) 0.55 mL/kg IM. Nonimmune pregnant women exposed to rubella who will not consider therapeutic abortion. Administration does not prevent rubella in the fetus of an exposed mother. 

Vitamin A is a necessary micronutrient in the diet for vision, growth, tissue differentiation, reproduction, and maintenance of the immune system. A deficiency of vitamin A affects reproduction in both male and female experimental animals. In the male, retinol is required for normal spermatogenesis in the female, the vitamin is necessary for both conception and normal development of the fetus. 

IgG Immunoglobulin G is present in lymph fluid, blood, cerebrospinal fluid and peritoneal fluid. It is composed of 2 y chains of 50 kDa and 2 L chains (k or ) of 25 kDa with a total molecular weight of 150 kDa. The functions of IgG include agglutination and formation of precipitate, passage through placenta and thus conferring immunity to fetus, opsonization, antibody-dependent cell-mediated cytotoxicity (ADCC), activation of complement, neutralization of toxins, immobilization of bacteria and neutralization of virus. 

Rho(D) immune globulin is one of the most specific and effective immunosuppressive treatments available. These IgG antibodies have high Rh(D)-specific titers. Administration of Rho(D) immune globulin prevents the response that develops in Rh mothers who were pregnant with an Rh+ fetus and consequently have become sensitized to the D antigen on fetal erythrocytes of the infant. In these Rh mothers, the antibody titers against Rh+ cells will continue to rise after each subsequent... 

Three epidemiologic studies in developing countries have failed to find definite evidence of impairment among heavy users of cannabis, but field studies may lack sensitivity. Experimental studies in which subjects have smoked heavily for varying periods have shown a lower serum testosterone level in men and airway narrowing. Reports of effects on immune mechanisms, chromosomes, and cell metabolism are often contradictory. Effects on the fetus are still uncertain. 

Increased HA levels in the bloodstream decrease immune competence.153 Various mechanisms have been invoked. An HA coating around circulating lymphocytes may prevent ligand access to lymphocyte surface receptors.95 96 154 155 The increased HA may represent one of the mechanisms for the immunosuppression in the fetus. The reappearance of high levels of HA in old age may be one of the mechanisms of the deterioration of the immune system in the elderly. The increasing levels of HA with aging may be a reflection of the deterioration of hydrolytic reactions, including the hyaluronidases that maintain the steady state of HA. This is a far more likely mechanism than an increase in HA synthase activity. 

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