TRANSPLANTATION IMMUNITY AND THE MATERNAL-FETAL RELATION

Blood group Rh-D factor in human trophoblast determined by immunofluorescent method

The chorionic villi of human placentas, 12 to 40 weeks' gestation, were examined for Rh-D blood group antigens with a direct immunofluorescent (IF) technique. Specific IF-standing was shown on the plasma membrane and cytoplasm of the villous trophoblasts. This staining decreased in intensity as the placenta matured. In addition, the trophoblasts of hydatidiform and destructive moles were also examined. The intensity of the IF-staining in these trophoblastic tumors was about the same as that in the young trophoblasts of the first trimester of pregnancy.

Histocompatibility antigens in pregnancy, abortions, infertility, preeclampsia, and trophoblast neoplasms

The genetic makeup of an individual may determine the capacity of the individual to combat successfully cancer and other disease states, eg abnormal pregnancies, abortions, infertility, and preeclampsia. These factors appear to be based upon the individual's immunogenetics, as histocompatibility-restricted T-cell cytotoxicity may be deficient in the observed instances of increased histocompatibility between husband and wife found in trophoblast tumor patients and in other instances of abnormal pregnancies.

Trophoblast transferrin and transferrin receptors in the host--parasite relationship of human pregnancy

Transferrin and specific transferrin receptors are demonstrated on the microvillous surface of syncytiotrophoblast in human immature and term placentae by immuno histological techniques with the use of light and electron microscopy. That the distribution of transferrin is limited to the materno-foetal interface supports the hypothesis that binding of maternal transferrin to trophoblast receptors is involved in the process of iron transport to the foetus. Parallel studies with baboon placentae demonstrate the presence of trophoblast receptors which bind both baboon and human transferrin, thereby putting forward an experimental model which might be used to test the biological significance of placental transferrin receptors in primates. In addition, investigation of a large number of human cell lines shows that many transformed cells, but no normal cells (such as blood lymphocytes) or cells from primary culture (such as neonatal foreskin fibroblasts), possess the ability to bind transferrin to their membranes. These findings suggest that transferrin receptors may play important biological roles in addition to that of iron transport from mother to foetus. One such role could be the limitation of iron in intervillous spaces, thus depriving iron-requiring microorganisms of iron, hence serving as a non-specific factor of resistance for placentae. Another role for foetal transferrin receptors on trophoblasts could be to bind maternal transferrin at the materno-foetal interface, thus frustrating maternal immunosurveillance. This is similar to a mechahism used by schistosomes in the host-parasite relation where host proteins are bound by the parasite to escape immunological recognition. The presence of transferrin receptors on transformed cells suggests that this mechanism might also be employed by tumour cells. Finally, in view of previous studies which show that transferrin is required by stimulated lymphocytes to pass from the G1 to the S phase of cellular replication, it is proposed that trophoblast transferrin receptors could limit the amount of transferrin in intervillous spaces and thus impede the proliferation and possible cytotoxicity of maternal activated lymphocytes at the materno-foetal interface.

Affinity chromatographic purification of the pregnancy zone protein

An immunospecific affinity chromatographic method for purification of human pregnancy zone protein (PZP) directly from serum is described. Highly purified goat-anti-human PZP-immunoglobulin was applied as a ligand. Recovery of PZP varied from 56--75%. The impurities constituted maximally 5--10% of the total protein in the eluate. The purification factor was approximately 100.

Metastatic choriocarcinoma involving the gingiva

A case of metastatic choriocarcinoma involving the mandible is reported. This case is analyzed for the potentiality of immunologic defense by utilizing tuberculin test and scoring the rate of blast formation of peripheral blood lymphocytes by phytohemagglutinin, resulting in a greatly decreased ability of cellular immunity.

Serum factors influencing spontaneous rosette formation by lymphocytes of pregnant women

The effect of sera from pregnant women on the percentage of spontaneous rosette-forming peripheral lymphocytes was investigated. Pregnancy lymphocytes displayed a significantly lower capacity to bind SRBC than control male lymphocytes. However, after an exhaustive washing, it was possible to demonstrate a significant increase of spontaneous rosettes formed by pregnancy lymphocytes. It was found that the incubation of pregnancy-washed lymphocytes with pregnancy but not homologous male serum restored to depressed levels the values of rosette-forming peripheral lymphocytes. This blocking activity was significantly higher with autologous serum than homologous pregnancy serum. Control lymphocytes were unaffected both by washing and by incubation with pregnancy sera. The blocking activity was found in the same ion-exchange chromatography fraction of pregnancy serum where paternal HLA antigens could be demonstrated, and was reproduced by a soluble HLA preparation from the husband's lymphocytes.

Immunobiological function of the syncytiotrophoblast: a new theory

The main purpose of this paper is to present our hypothesis concerning the antigen-antibody complex formation and the resolution system inside the syncytiotrophoblast to explain immunologic fetomaternal relationships. This hypothesis, derived from the results of our experiments, might be an answer to why the fetus is not rejected by the mother, in contradistinction to other allografts. We also believe that this hypothesis makes important contributions to the explanation of the immunologic processes of cells, i.e., those processes which work against antigens inside a living body.

Choriocarcinoma in Ibadan: clinicopathologic studies

The host tissue reaction to choriocarcinoma was studied in 81 Nigerian patients. A mononuclear cellular reaction, observed in about 42 per cent of the patients, was composed mainly of lymphocytes, plasma cells, histiocytes, and eosinophils in varying quantities around tumor deposits. No correlation was found between the survival of the patients and the intensity of the cellular reaction. Late presentation by our patients for medical advice and treatment may partly account for the relatively poor response to chemotherapy. The syncytiotrophoblast appears to play a primary role in vascular invasion by the neoplastic trophoblast.

Immunoglobulins and beta-1-C globulin in hydatidiform mole vesicles

Qualitative and quantitative determinations of immunoglobulins (Ig's) and beta-1-C globulin were carried out in fluid vesicles of hydatidiform moles and carrier mothers. The mean concentration of IgG was 9.9 per cent, IgA had 14.3 per cent, in relation to maternal values. No IgM concentrations were detected in molar fluid. Beta-1-C globulin showed 60.5 per cent concentration in relation to mother's serum. It is suggested that in trophoblast of molar vesicles a selective transudate migration of Ig's by a mechanism of pinocytosis takes place to the vesicular fluid.

Burkitt's lymphoma of the ovary in association with pregnancy. Two case reports

Burkitt's lymphoma of the ovary, occurring in association with pregnancy, is rare, only one case having been previously reported. Two cases are reported here and the possible effect of pregnancy discussed.

Immunologic aspects of term pregnancy toxemia. A study of immunoglobins and complement

IgA, IgG, and IgM were measured by the single radial immunodiffusion method in umbilical cord and maternal sera in toxemia patients and in normal term pregnant cases. Complement (C' 3) levels were determined only in maternal sera. Quantitation of IgA, IgG, and IgM was performed in concentrated serial urine samples from three eclamptic and three normal control patients. Results show that there are lower IgG and IgM levels in the sera of mothers with toxemia of pregnancy; however, paradoxically higher IgM levels were detected in cord sera from their newborn infants without evidence of placental leakage or increased neonatal infection. The finding of the low IgG and IgM levels appears to be due in part to immunoglobin loss into the urine. The unchanged complement levels in toxemia, in this study, are not suggestive of an active immunologic process, but the high IgM in the newborn infants of toxemic mothers is unexplained and may represent active immunologic disease. Clearly, investigations of tissue binding and the formation of immunoglobin complexes should be carried out to better explain these abnormal findings.

[Antigens of the human placenta (author's transl)]

The immunologic relations between mother, foetus and placenta are discussed and those antigens of the human placenta already characterized by their physico-chemical and immunochemical properties described. In diagnostics the detection and determination of placental proteins is used in pregnancy tests, for the evaluation of placental functions and the detection of malignant diseases. Antibodies to placental antigens have an abortive effect; immunization against placental specific proteins may have implications as an immunologic contraceptive method and for the immunotherapy of choriocarcinoma.

Inhibitory effect of progesterone on the phytohaemagglutinin- induced transformation of human peripheral lymphocytes

Effect of sex steroids, progesterone and estradiol-17beta, on transformation of human lymphocytes induced by PHA was investigated. Responses of peripheral lymphocytes from non-pregnant women to PHA was markedly reduced in the presence of progesterone at a concentration of 10(3) or 10(4) ng/ml. Estradiol-17beta, on the other hand, had no effects on the PHA-induced transformation under the present experimental conditions. The immunosuppressive property of progesterone may contribute to depression of maternal cell-mediated immunity against fetus during pregnancy.

Immunological studies of the human placenta. Characterization of immunoglobulins on trophoblastic basement membranes

Immunohistological and elution studies of the human placenta revealed the presence of IgG on the trophoblastic basement membrane (TBM) which demonstrated specificity for placental but not lung, thyroid, or kidney basement membranes, suggesting the presence of a placenta-specific antigen in TBM. IgG comprised the bulk of immunoglobulin in eluates, and small amounts of IgA, trace amounts of IgM, but no IgE or IgD were identified in eluates. The distribution of IgG subclasses in eluate was not unusual as compared to maternal and neonatal sera, and Gm and Inv typing of eluates indicated that it was of maternal origin. Small amounts of eluate-IgG effectively inhibited the blastogenic response of unrelated lymphocytes to old tuberculin, phytohemagglutinin, and in one- or two-way mixed lymphocyte culture reactions. The inhibition was distinct from nonspecific inhibitors, and dose-response analysis indicated that eluate was very much more potent as an inhibitor than were the nonspecific inhibitors. Inhibition was shown to not be due to anti-HL-A activity, and was probably not due to aggregated IgG or immune complexes. Binding of eluate to lymphocytes was very loose as shown by washing experiments, and no binding could be shown by immunofluorescence. The capacity of eluate IgG to inhibit MLC was retained after pepsin digestion to F(ab')(2), suggesting that the inhibition reactions were immunological. It is suggested that eluate-IgG is maternal blocking antibody to a hitherto uncharacterized trophoblast antigen, and it is speculated that either abnormal antigen or aberrant responses to antigen could result in fetal wastage.

Human chorionic gonadotropin: its possible role in maternal lymphocyte suppression

Human chorionic gonadotropin completely inhibits the response of lymphocytes to phytohemagglutinin. The effect is both reversible and noncytotoxic. These observations support the theory that the fetus is accepted because human chorionic gonadotropin represents trophoblastic surface antigen and blocks the action of maternal lymphocytes.

Differential immunofluorescence of fertilized mouse eggs with H-2 and non-H-2 antibody

Mouse embryos at the two-cell and blastocyst stages, as well as unfertilized eggs, have been studied by indirect immunofluorescence for the expression of H-2 and non-H-2 histocompatibility antigens on surface membranes. Serologically-specific reactivity to non-H-2 antibody (H-3 and H-6) was observed as diffuse, patchy staining over the entire surface of the blastomeres at the two-cell stage. In contrast, no reactivity of two-cell or unfertilized egg embryos of four inbred strains was observed when antisera containing only multispecific H-2 cytolytic antibody were used. Antisera containing H-2 along with non-H-2 antibody of unknown specificity showed varying degrees of reactivity, which could be shown by absorption studies to be due to the non-H-2 content of the serum. The results suggest that the initial expression of histocompatibility genes varies and support the hypothesis that the appearance of these cell components may relate to specific stages of differentiation.

Sex ratio of newborns: preponderance of males in toxemia of pregnancy

The ratio of males to females in 1061 babies born to mothers with toxemia of pregnancy is 1.24. The ratio increases as the severity of the disease increases, being 1.71 in cases in which the urinary output of protein is equal to or greater than 3 grams per 24 hours. Histoincompatibility of the fetus and mother, including incompatibility due to an antigen (or antigens) dependent on the Y chromosome, is suggested to function in the pathogenesis of pregnancy toxemia.