Immunologic sensitization prior to birth

Schistosoma japonicum: susceptibility of neonate mice born to infected and noninfected mothers following subsequent challenge

This study was to investigate the differences between neonate mice born to Schistosoma japonicum-infected mothers and those born to noninfected mothers in subsequent challenge. The intensity of infection (evidenced by worm burden and liver egg burden) and liver immunopathology (number and size of liver granulomas) were significantly reduced in neonates from infected mothers (I.M.) compared with neonates from noninfected mothers (N.M.). Anti-soluble worm antigen of S. japonicum (SWA) IgG could be detected in sera of neonates from I.M. (N.N./I.M.) at 1 week after delivery, remained a plateau for 2 weeks and gradually decreased until 8 weeks of age. Parasite-specific IgM was not detected in sera from N.N./I.M. at any time after delivery. At 6 weeks after infection, the level of anti-SWA IgG in infected neonates from I.M. (I.N./I.M.) was significantly higher than that of infected neonates from N.M. (I.N./N.M.). In addition, production of IFN-γ, IL-12 and TGF-β by cultured splenocytes from I.N./I.M. was significantly increased, while the level of IL-4 was significantly decreased when compared to those from I.N./N.M.. These data demonstrate that congenital exposure to schistosomiasis japonica may render neonatal mice born to I.M. less susceptible to subsequent challenge and result in down-regulation of both infection intensity and immunopathology.

Susceptibility of neonate mice born to Schistosoma mansoni-infected and noninfected mothers to subsequent S. mansoni infection

The present study tested the hypothesis that prenatal exposure of neonate Outbred albino mice to Schistosoma mansoni antigens (Ags) or antibodies (Abs) modulates their immunity against postnatal responses to infection. Persistence of maternal S. mansoni Abs and/or Ags in mice born to S. mansoni-infected mothers (IF-IMs) and noninfected mothers (IF-NMs) for up to 8 weeks after delivery was investigated. A higher level of anti-S. mansoni IgG Ab was detected in sera of 1-week-old mice born to IF-IM compared to controls. Then, immunoglobulin (Ig)G gradually decreased to the eight week. No anti-S. mansoni IgM Ab was detected in sera of these offspring at any week after delivery. Schistosoma Ags were detected in liver and kidney tissues of mice born to infected mothers. However, Ags decreased markedly till the sixth week in the liver but increased significantly at the sixth week in the kidney. Eight-week-old mice born to infected and noninfected mothers were infected with 200 S. mansoni ceracriae. Their sera and livers were collected for testing IgG and granuloma formation 6 weeks postinfection. Worms were collected via portal perfusion and counted. Anti-S. mansoni IgG level, size and number of liver granuloma, and worm burden were significantly reduced in the offspring of infected mothers. These data suggest that in utero exposure of Outbred albino mice to S. mansoni may attenuate the pathogenesis of S. mansoni in subsequent challenge.

Slow, programmed maturation of the immunoglobulin HCDR3 repertoire during the third trimester of fetal life

The mean distribution of lengths in the third complementarity-determining region of the heavy chain (HCDR3) serves as a measure of the development of the antibody repertoire during ontogeny. To determine the timing and pattern of HCDR3 length maturation during the third trimester of pregnancy, the mean distribution of HCDR3 lengths among variable-diversity-joining-constant-mu (VDJC(mu)) transcripts from the cord blood was analyzed from 138 infants of 23 to 40 weeks' gestation, including 3 sets of twins, 2 of which were of dizygotic origin. HCDR3 maturation begins at the start of the third trimester; follows a slow, continuous expansion over a 5-month period; and is unaffected by race or sex. The range and mean distribution of lengths may vary in dizygotic twins, indicating individual rates of development. The mean HCDR3 length distribution in 10 premature infants with documented bacterial sepsis was then followed for 2 to 12 weeks after their first positive blood culture. HCDR3 spectrotype analysis demonstrated oligoclonal B-cell activation and expansion after sepsis, but maturation of the repertoire was not accelerated even by the systemic exposure to external antigen represented by bacteremia. Antibody repertoire development appears to be endogenously controlled and adheres to an individualized developmental progression that probably contributes to the relative immaturity of the neonatal immune response.

IgM Heavy Chain Complementarity-Determining Region 3 Diversity Is Constrained by Genetic and Somatic Mechanisms Until Two Months After Birth

Due to the greater range of lengths available to the third complementarity determining region of the heavy chain (HCDR3), the Ab repertoire of normal adults includes larger Ag binding site structures than those seen in first and second trimester fetal tissues. Transition to a steady state range of HCDR3 lengths is not complete until the infant reaches 2 mo of age. Fetal constraints on length begin with a genetic predilection for use of short DH (D7-27 or DQ52) gene segments and against use of long DH (e.g., D3 or DXP) and JH (JH6) gene segments in both fetal liver and fetal bone marrow. Further control of length is achieved through DH-specific limitations in N addition, with D7-27 DJ joins including extensive N addition and D3-containing DJ joins showing a paucity of N addition. DH-specific constraints on N addition are no longer apparent in adult bone marrow. Superimposed upon these genetic mechanisms to control length is a process of somatic selection that appears to ensure expression of a restricted range of HCDR3 lengths in both fetus and adult. B cells that express Abs of an “inappropriate” length appear to be eliminated when they first display IgM on their cell surface. Control of N addition appears aberrant in X-linked agammaglobulinemia, which may exacerbate the block in B cell development seen in this disease. Restriction of the fetal repertoire appears to be an active process, forcing limits on the diversity, and hence range of Ab specificities, available to the young.

Relationships between maternal malaria and malarial immune responses in mothers and neonates

Immune responses of 97 Gambian women and their neonates were studied. New methods distinguished between active and previous placental malaria, were used to examine relationships between maternal malaria and neonatal immune responses. Many placentas (61%) had active or previous malarial infection. Maternal and cord malarial IgG levels correlated (P < 0.001). Malarial IgG was raised in cord blood in active placental malaria; IgM was not detected. Mean lymphoproliferation and the proportion of responders to soluble P. falciparum antigens (F32) and conserved regions of p190 expressed on trophozoites and schizonts (190L and 190N) were higher in neonates than mothers. There was no clear relationship between maternal malaria and neonatal mean lymphoproliferation to malarial antigens, although fewer neonates responded when mothers were actively infected. Matched maternal and neonatal lymphoproliferation responses did not correlate. However, first born neonatal lymphoproliferation to PPD and malarial antigens appeared lower than other neonates, in agreement with lower lymphoproliferation in primigravidae compared with multigravidae. Also in common with mothers, autologous plasma suppressed neonatal lymphoproliferation to PPD and malarial antigens, suggesting common immunoregulation. Higher cortisol or other circulating factors in first pregnancies may be implicated. The relevance of cell-mediated malarial immune responses detected at birth remains to be established.

Maternal infections influence infection susceptibility in childhood

The proposed hypothesis suggests that the types of infections commonly experienced in pregnancy and in childhood are linked. The suggestion is made that maternal infections leave an impression on the developing fetal immune system and modulate future responsiveness to infection and/or vaccination challenge. A number of factors are explored which may influence this process, namely immunoregulation in pregnancy and infection type, gestation, maturity of the fetal immune system, and parity.

Immunology of pregnancy: towards a unifying hypothesis

The variable findings of hormonal-immunoregulation and the variable cellular and humoral immune responses in pregnancy have been considered in relationship to the physiological response. From such considerations it appears that the peripheral blood lymphocyte/leukocyte response in pregnancy is not important, but rather the local uterine immune response at implantation and throughout pregnancy. It is proposed, and evidence is presented, that a normal allogeneic immune response is initiated at the time of implantation of the blastocyst. This immune response regulates the invasive nature of the trophoblast and initiates the first stage of parturition. The initiation and maintenance of this immune response is based on an interplay between maternal and paternal HLA and trophoblast antigens. In the case of HLA-incompatible donor-recipient blastocyst transplants, a more pivotal role for immunoregulation by trophoblast antigens is proposed. This is because it is considered that the local uterine immune response suppresses the expression of allogeneic HLA. This concept is further developed in terms of haploid HLA suppression on maternal and fetal lymphocytes that cross the placenta. This is considered to allow the interaction of these lymphocytes with each other and explains maternal transfer of cell-mediated immunity.

Immune response of the atopic woman and foetus: effects of high- and low-dose food allergen intake during late pregnancy

The influence of the mother's consumption of cows' milk and hens' egg on the immune response (IgE, IgG) in the mother and foetus was studied in 165 pregnant women with atopical respiratory disease with an allergy to pollen and/or animal dander. The women were randomly allocated to four diets ranging from a diet free from hens' egg and cows' milk to a diet containing intake of one egg and one litre of milk daily during the third trimester. No significant differences in cord blood IgE levels were noted in spite of differences in maternal diet, and no specific IgE antibodies to ovalbumin, ovomucoid and betalatoglobulin were found in the cord blood. The mother's IgG antibody concentrations to ovalbumin, ovomucoid and betalactoglobulin were influenced by her diet, but cord blood IgG antibody levels to the selected food allergens were unaffected. The data presented on the IgE and IgG antibody levels to ovalbumin, ovomucoid and betalactoglobulin in cord blood suggest that changes in maternal diet during the last trimester of pregnancy in order to prevent atopic sensitization in utero are less likely to affect the foetus than previously supposed.

Antibodies to the oral bacterium Streptococcus mutans and the development of caries in children in relation to maternal dental treatment during pregnancy

These factors were studied in 50 children, aged 3.6 to 5.9 years. Children of mothers who had no dental treatment during pregnancy (NTP-group, n = 25) had significantly (p less than 0.02) more serum IgG antibodies reactive with Strep. mutans than those of mothers who received such treatment (TP-group, n = 25). The children in the NTP-group had fewer Strep. mutans, a higher proportion of intact dentitions, lower dmfs/DS-index and lower caries incidence than those in the TP-group. Over one year of follow-up, a significantly greater proportion of children in the TP- than in the NTP-group developed new caries (p less than 0.05). Thus, maternal dental treatment during pregnancy may affect caries development in the primary dentition of the child, possibly via transplacental immune mechanisms.

The effect of maternal antigenic stimulation upon the active immune responsiveness of their offspring: suppression induced by soluble protein antigen, ovalbumin, in mice

The active immune responsiveness of the offspring of pregnant mice stimulated with heterologous protein antigen was investigated by measuring the plaque-forming cells (PFC). Mice (C57BL/10;B10) immunized once in pregnancy with ovalbumin (OVA) in the form of Al(OH)3 gel (in alum) or in a soluble form (in saline) developed no anti-OVA PFC response. The anti-OVA PFC response suppression induced in the offspring was high in the offspring of alum-treated mothers and low in those of saline-treated mothers. The optimal dose of OVA in alum that induces the highest immunological memory in pregnant mice caused the complete suppression of PFC development in their offspring. The same dose of OVA in saline induced a negative immunological memory in pregnant mice and partial suppression in the offspring. On the other hand, mice primed prior to conception and boosted during pregnancy developed anti-OVA PFC in significant numbers, and only a partial suppression was established in their young. Based on these data, we discussed the possible mechanisms concerned with the specific suppression induced in the young B10 mice stimulated by OVA.

In utero immunization of the fetus to tetanus by maternal vaccination during pregnancy

We tested 36 pairs of umbilical cord blood and maternal sera collected at the time of delivery by radioimmunoassay and by Western blot analysis for IgG or IgM antitetanus antibodies (anti-TT). Twenty-one participants had received a recall injection of tetanus toxoid at various periods during pregnancy. Maternal vaccination in the last trimester of pregnancy was associated with the presence of IgM anti-TT in the cord blood sera; these were not detected in neonatal sera from mothers who were not vaccinated during pregnancy or who received the booster injection during the first two trimesters of gestation. The results could not be ascribed to artifacts such as the contamination of neonatal sera by maternal blood, the contamination of the anti-IgM antisera by antiidiotypes, or by the presence of neonatal IgM rheumatoid factor binding to immune complexes made of maternal IgG anti-TT and radiolabelled TT. Hence, it is concluded that maternal vaccination during the last trimester of pregnancy may induce in utero active immunization of the fetus.

Effect of maternal antigenic stimulation on the active immune response of their offspring. Relationship between the immune reactivity of mother mice and the induction of suppression in their young

Pregnant mice were stimulated by heterologous erythrocyte and protein antigen, and the active immune responses of their offspring as measured by plaque-forming cells (PFC) were investigated. In offspring derived from mothers immunized by a suitable amount of T-dependent antigen, clear-cut suppression of development of specific PFC in spleen was observed over a significant period after delivery. The mechanism of this suppression was investigated, and the following results were obtained. When the heterologous erythrocyte was used as antigen, the more the specific PFC developed in the mother spleen, the stronger the suppression of PFC observed in their offspring. However, it is worthy of note that passive administration of antibody to pregnant mice did not induce suppression in their young. In case of the protein antigen ovalbumin (OVA), pregnant mice had to be injected with a suitable amount of antigen, along with aluminium hydroxide, for either primary or secondary stimulus to induce the suppression of specific PFC in their offspring. Soluble OVA administered to pregnant mice was not effective for inducing suppression in the offspring. Based on these results, some possible mechanisms are discussed concerning specific PFC suppression in the offspring when pregnant mice are stimulated.

Recurrent acute otitis media in infants--role of immune complexes acquired in utero

Ten infants experiencing recurring episodes of acute otitis media with associated otitis media with effusion while on human breast milk afford a study of the role of possible immune complexes acquired in utero through the mother's allergic diathesis. Seven of the 10 children were on the breast when first seen. Challenge feeding tests determined the mothers' hypersensitivities. Those infants breast fed by mothers exhibiting positive challenges to specific foods, manifest allergic responses themselves following the first breast feeding after the mothers' challenge. A cessation of episodes of AcOM and OME occurred in five of the series as foods proven to be offenders were eliminated from the mother's and child's diet. Degrees of failure were experienced in the remainder, varying as to the severity and cause.

Functional bacterial opsonic activity of human amniotic fluid

There are some data to suggest that amniotic fluid protects the fetus from invasion by pathogenic bacteria. To examine methods by which amniotic fluid may offer such protection, quantitative antibody, complement activity, and functional opsonic capacity were measured. Immunoglobulins were measured by laser nephelometry and total hemolytic complement was determined by radial diffusion; results suggested activity adequate for bactericidal capacity. The chemiluminescence assay was used to quantitate the functional interaction between polymorphonuclear leukocytes and E. coli, group B streptococci (GBS), or zymosan particles preopsonized with amniotic fluid obtained at different stages of gestation. Results were compared to those for normal serum. Data were analyzed by evaluation of the initial slope, area under the curve, and peak chemiluminescence response. Opsonic activity of amniotic fluid for E. coli and GBS was demonstrated, with E. coli showing greater reactivity (maximum = 15,000 to 25,000 cpm) than GBS (10,000 to 20,000 cpm). Specific, as well as nonspecific, opsonic activity was demonstrated by absorption of amniotic fluid with killed bacteria. Concentration of amniotic fluid did not result in an increase in chemiluminescent activity, which demonstrates that optimal opsonic activity already exists. The classical and alternate pathways of complement were assessed for E. coli and GBS. Preterm amniotic fluid did not differ in response from that of amniotic fluid obtained from term pregnancies. This study demonstrates that amniotic fluid can provide the fetus with protection from bacterial pathogens and delineates mechanisms for such protection.

Passage of zona antibodies via placenta and milk following active immunization of female mice with porcine zonae pellucidae

Female mice heteroimmunized with heat-solubilized porcine zonae produced a significant antibody response to this immunogen as measured by radioimmunoassay (RIA) but their fertility was unaffected and normal litters were delivered. Monitoring for anti-zonae pellucidae activity in the sera of offspring from such immunized mothers by RIA indicated that the zonae antibodies were transferred from mother to young via the placenta and milk. Such transferred antibodies cross-reacted with and bound to the zonae of female offspring as demonstrated by immunofluorescent techniques. These data are significant to the future consideration of use of specific zona antigens for development of a contraceptive vaccine.

Intestinal absorption of immune complexes by neonatal rats: a route of antigen transfer from mother to young

Horseradish peroxidase (HRP) in the presence of specific immunoglobulin G antibody to HRP is selectively absorbed from the gut lumen and transferred by intestinal epithelial cells to the lamina propria in newborn rats. The HRP is not transferred in detectable amounts in the absence of the antibody. Transport of maternally derived antigen via antigen-antibody complexes may have important influences on the developing immune system in young mammals.

Relationship between the responsiveness of maternal and foetal lymphocytes to phytohaemagglutinin and to microbial antigens

The response of 105 maternal-foetal lymphocyte pairs to specific and non-specific stimulation were evaluated using a newly defined method of analysis. There were no significant differences in the responses of maternal or foetal lymphocytes to phytohaemogglutinin (PHA) or the various antigens as a function of concentration over the ranges tested. The maternal lymphocytes were stimulated by all of the antigens and responded to PHA three--five times more strongly than to the antigens. The foetal lymphocytes were stimulated by PHA and tetanus toxoid only and were suppressed by streptokinase-streptodornase (SKSD). They responded to stimulation by antigens at a lower level than did the maternal lymphocytes, but they responded at a much higher level to PHA. Unstimulated cultures of foetal lymphocytes incorporated more isotope than did those of maternal lymphocytes in both autologous and AB plasma. The data were cross-classified to determine whether the responses of the foetal lymphocytes varied concordantly with the responses of the maternal lymphocytes in both autologous and AB plasma by the Chi-square test for independence and by rank correlation analysis. There was no significant correlation in either plasma to stimulation with the antigens. Thus, the presence of antigen reactive lymphocytes in the circulation of the mother does not mean that the foetus is sensitized to that antigen. Comparison of the lymphocyte responses in autologous plasma with those in AB plasma provided evidence for the presence of circulating immunoregulatory substances. Autologous maternal plasma suppressed the lymphocyte responses to high concentrations of candida and SKSD and stimulated the response to mumps, varicella and tetanus toxoid. Autologous fetal plasma suppressed the lymphocyte responses to candida, varicella and SKSD and stimulated the response to PHA. The responsiveness of maternal lymphocytes to PHA was less in foetal plasma than in autologous maternal or AB plasma.

Mother-child relation in human schistosomiasis mansoni : skin test and cord blood reactivity to schistosomal antigens

Reaction to schistosomal antigen was studied in children born to mothers infected with Schistosoma mansoni. Values of immediate (15 min) skin reactions were more elevated and values of delayed (24 h) skin reactions were significantly higher in children born to infected mothers than in children born to uninfected mothers. The macrophage migration inhibition test, done on cord blood cells, was positive to schistosomal antigen in 40% of children born to infected mothers and negative in all children born to uninfected mothers. These results suggest prenatal sensitization to schistosomal antigen in children born to mothers infected with S. mansoni.

Immunological tolerance: transmission from mother to offspring

Mice born and raised by mothers made specifically unresponsive to heterologous erythrocytes by prior treatment with soluble extracts of these cells become themselves tolerant. Tolerance is achieved through nursing since normal neonates fostered by tolerant animals become tolerant, while animals born to tolerant mothers but nursed by normal mice are fully responsive.