CELL SENSITIZATION TO HELMINTHIC INFECTION DEVELOPS IN-UTERO IN HUMANS

Human neonates are generally deficient in their ability to generate hu moral immunity, This deficiency is thought to reflect physiologic imma turity of T and B cell function and lack of previous exposure to exoge nous Ags, To determine whether neonatal humoral immunity can be modifi ed by maternal helminth infection during pregnancy, we assessed Ig pro duction by cord blood lymphocytes from healthy newborns of mothers liv ing in an area of Kenya,where schistosomiasis, bancroftian filariasis, and geohelminth infections are endemic, Twelve of 40 and 17 of 39 cor d blood lymphocyte preparations from healthy newborns in Coast Provinc e, Kenya, spontaneously made polyclonal IgE (range, 0.15-21 ng/ml) and IgG (1.6-10.1 ng/ml) in vitro, In vitro IgE synthesis by cord blood l ymphocytes (CBL) was, on the average, 10-fold less than that of PBMC o f Kenyan mothers (1.1-98 ng/ml) and was undetectable for CBL from newb orns delivered in the United States, Schistosome and filarial Ags stim ulated a 3- to > 100-fold increase in the production of polyclonal IgE and parasite-specific IgG Abs by lymphocytes from 10 of 40 and 6 of 3 9 Kenyan newborns, respectively, CBL observed to have helminth Ag-driv en B cell responses were more likely to be from newborns of schistosom e-or filaria-infected mothers than from uninfected mothers (p < 0.05), These data indicate that the human fetus can be sensitized in utero t o produce hehninth-specific B cells and that neonatal B cells are intr insically capable of IgE and IgG production.