Immune Responses During Human Schistosomiasis Mansoni. XVIII. Immunologic Status of Pregnant Women and Their Neonates

Abstract

The immune status of peripheral blood mononuclear cells (PBMC) and sera of pregnant women infected with the helminth Schistosoma mansoni was studied during pregnancy and the cord blood mononuclear cells (CBMC) and sera from their offspring were studied at parturition. PBMC pokeweed mitogen-induced responses were maintained in gravid women, but the responses to both schistosome and non-schistosome antigenic preparations declined progressively during pregnancy. Schistosomal antigens stimulated proliferative responses by the CBMC of many neonates born of infected mothers, but not those of uninfected mothers. These specific responses by CBMC of only neonates born of infected mothers are indicative of in utero, cell-mediated sensitization of the neonates, which could be due either to circulating schistosomal antigens or to anti-idiotypic antibodies which cross the placenta during gestation. Sera from infected mothers and the cord blood sera from their babies showed the same levels of specific IgG anti-schistosomal activity. Anti-schistosomal IgM levels were maintained during pregnancy to some antigens and not to others, while such antibodies were rarely found in cord blood sera, and then only at very low levels.

Experimental models of Schistosoma mansoni infection

“…Most humans exposed to schistosomiasis are born to mothers who are or have been infected. There are ample reasons to think that in utero exposure to schistosome antigens or to idiotypic or anti-idiotypic antibodies may modify the response to subsequent infection in humans (Eloi-Santos et al 1989, Novato-Silva et al 1992) and in mice (Montesano et. al.…”

Placental and Oral Delivery of Schistosoma Mansoni Antigen From Infected Mothers to Their Newborns and Children

“…13 Exposure to maternal antigens might predispose a child to develop an immunoregulated, asymptomatic clinical presentation of the infection, and may predispose them to respond with an altered, perhaps more immunoregulated, form of schistosomiasis. 4,5,14 The probably immunogenic effects of such antigens as vaccines among infected mothers and the proper time to vaccinate newborns need to be studied.…”

“…3 Exposure to maternal schistosome antigens might also predispose a child to respond with an altered, perhaps more immunoregulated form of schistosomiasis. 4,5 Thus, defining the extent to which maternal schistosome antigens may or not interfere with responses to new infant vaccines requires a better understanding of its main determinants.…”

Association of In Utero Sensitization to Schistosoma haematobium with Enhanced Cord Blood IgE and Increased Frequencies of CD5– B Cells in African Newborns

“…King and others 3 reported that in vitro filarial and/or schistosome antigen-driven IgE production was more likely to be seen in newborns of schistosome-infected or filaria-infected mothers than in offspring of uninfected mothers. Other studies also showed enhanced levels of schistosome-specific antibodies in cord blood 14,[17][18][19] but did not discriminate between children of infected and uninfected mothers, 18 did not state whether an admixture of maternal to the fetal blood was excluded, 14,[17][18][19] or did not differentiate between the distinct antibodysubtypes. 14,17,19 Therefore, it is possible that the latter studies detected maternal IgG that crossed the placental barrier.…”