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C A Shivers

Publications and source records attributed to C A Shivers.

7 recordsLinked to original sources
PubMed1978

Antigenic cross-reactivity between human and marmoset zonase pellucidae, a potential target for immunocontraception.

Cross-reactivity between marmoset, chimpanzee, human and pig zona pellucida antigens was demonstrated by immunofluorescence and zona precipitation. In marmosets, anti-zona antibody prevented sperm attachment to eggs in vitro, and the antibody could be detected on zonae of ovarian oocytes following passive immunization. Use of the marmoset as an animal model in testing feasibility of the zona approach to immunocontraception is discussed.

Animals↗
PubMed1977

Autoantibodies to zona pellucida: a possible cause for infertility in women.

Human and pig ovaries were tested by agar gel diffusion and found to contain several cross-reacting (common) antigens. At least one common antigen was located in the zona pellucida as determined by indirect immunofluorescence. Serum samples from 22 infertile women were tested on pig eggs by immunofluorescence, and six of these samples produced strong and nine produced moderate reactions with the zona pellucida. The autoantibodies may be responsible for infertility in these women.

Animals↗
PubMed1976

Immunological aspects of sperm receptors on the zona pellucida of mammalian eggs.

Sperm receptor sites on the surface of the zona pellucida are believed to be necessary for fertilization on the mammalian egg. Ovary specific antibodies are known to precipitate the zona pellucida and are also responsible for inhibition of sperm binding and subsequent fertilization. The nature of the proposed receptor sites which are blocked by antibodies are discussed relative to comparable studies in which phytoagglutinins and other agents are used to determine the chemical nature of sperm receptor sites.

Animals↗
PubMed1975

Detection and localization of specific antigens in the reproductive tracts of cycling, pregnant, and ovariectomized hamsters.

A systematic search was made for components specific to the female reproductive tract in golden hamsters. Antisera produced in rabbits against saline homogenates of hamster uteri (collected on the night of estrus) cross-reacted extensively with extracts of 12 other tissues in agar gel double-diffusion assays. Absorption of the antisera with small intestine, lung, and liver rendered the immune sera specific for uterine and oviductal antigens (within the limits of the sensitivity of the precipitin assays). Immunoelectrophoretic analysis resolved 12 uterine antigens, many of which were similar to components in several other tissues. Absorbed antisera specific for reproductive tract antigens formed one postalbumin arc with uterine and oviductal extracts in immunoelectrophoretic studies. No reactions were detected between specific antisera and five other organ extracts or plasma. An indirect immunofluorescent antibody technique was used to detect changes in the distribution of specific antigens in reproductive tracts of cycling, pregnant, and ovariectomized hamsters. The gamma-globulin fraction of anti-uterus sera (absorbed with small intestine, lung, and liver), shown to be specific for reproductive tract tissues in precipitin tests, was used to localize antigens. Appropriate controls indicated that the fluorescence observed was due to antigen-antibody interactions. During the cycle, specific antigens were usually confined to the ampullary lamina propria, except during estrus, when they were prominent in the lamina propria and luminal epithelium of the ampula. Specific antigens were never abundant in the isthmus of nonpregnant hamsters. On day 1 postcoitum, the components were found throughout the ampullary and isthmic regions. By day 2 postcoitum, ampullary antigens were usually confined to the lamina propria. The specific components were not prominent in the oviduct on day 3 postcoitum, but were conspicuous in both ampulla and isthmus on day 4. Specific antigens in the uterus were confined to endometrial glands in nonpregnant animals during proestrus, estrus, and (occasionally) metestrus. Diestrous uteri contained no specific antigens. During the first 2 days of pregnancy, antigens were not abundant and were usually confined to the glands and stroma. On days 3 and 4 of pregnancy the specific antigens were prominent in the endometrial glands and stroma and along the apical borders of some luminal epithelial cells. By day 5, these components were less conspicuous in all areas of the endometrium. Uteri of spayed animals receiving no hormones or estradiol alone lacked the specific antigens. However, progesterone (after estrogen priming) promoted the appearance of these components, and the distribution resembled that seen in uteri of 3- and 4-day pregnant animals.

Animals↗
PubMed1975

Immunologic evidence for addition of oviductal components to the hamster zona pellucida.

An indirect immunofluorescent procedure was used to determine whether zonae of unfertilized and fertilized eggs would bind antibodies specific for hamster reproductive tract antigens. Appropriate controls indicated that the fluorescent staining was probably due to antigen-antibody interactions. Antigens were not detected in zonae of ovarian eggs. However, components in zonae of unfertilized eggs collected from the oviduct at metestrus, mid-diestrus, and late diestrus bound antibodies specific for oviductal and uterine antigens. The antigens appeared to be concentrated in a peripheral band within the zona. An outer area of the zona around the eggs obtained from the uterus at proestrus also bound the antibodies, although the fluorescent staining was relatively faint. Antigens were observed in the peripheral area of zonae of fertilized eggs collected from oviducts on days 1 and 2 postcoitum. However, the antibody-binding component of the zona was noticeably reduced in embryos taken from the uterus on day 3 of pregnancy. The results are consistent with the idea that the zonae of both unfertilized and fertilized hamster eggs are composed of layers and that the outer region contains specific antigens which are dereived from the oviduct. Furthermore, loss or alteration of these components in the zona of an embryo (but not of an unfertilized egg of the same postovulation age) may reflect some chemical or structural change which is a prerequisite for zona shedding. Anti-uterus sera (unabsorbed and absorbed) did not interfere with zona removal by trypsin, indicating that the antigens detected in the present study are different from the receptor sites which bind anti-ovary antibodies and certain plant agglutinins (as reported by other workers).

Animals↗
PubMed1975

Immunological interference with fertilization.

Rabbit antisera against mouse and hamster ovaries and sheep antisera against rabbit ovary have been used to demonstrate ovary specific antigens in these three species of mammals. That one or more of the specific antigens are located in the zona pellucida which surrounds the egg was indicated in immunofluorescence studies and by the effects antibodies have on the zona. After exposure to the antibody a precipitate forms on the zonae of preovulatory, unfertilized and fertilized eggs and all embryonic stages up to the time when the zona is shed. The precipitate was always seen near the outer surface of the zona suggesting that the active sites of the antigen(s) are located in this region. Trypsin and pronase which usually dissolve the zona were ineffective on the precipitated outer portion but did dissolve the inner, unprecipitated region. Species- and tissue-specificity and chemical nature of the zona are discussed. Important roles for the zona antigen(s) in a number of early events in reproduction were indicated by the effects of antizona antibodies have on fertilization and implantation. Pretreatment of unfertilized hamster eggs with zona precipitating antibodies was most effective in blocking sperm attachment to the zona. When the antibody was added subsequent to in vitro insemination, but before the sperm had passed through the outer region of the zona, sperm penetration was blocked. Mouse embryos treated with zona precipitating antibody and cultured in vitro failed to escape from the zonae, implying that implantation could be inhibited by antibody. Passive immunization of female mice with antizona antibodies and precipitattion of the zonae of hamster embryos in transfer experiments reduced the number of implantation sites. The identification of zona antigens and the effects of zona precipitating antibodies on early reproductive events encourage further studies on the zona in reference to immunological control of fertility.

Animals↗