Maternal dietary antigens and the immune response in the offspring of the guinea-pig

Guinea-pig dams and their litters were raised on either a cow's milk protein-containing diet (MCD) or a milk-free diet (MFD). At 8 weeks of age all litters were challenged i.p. with 50 μg milk whey-protein concentrate (v67) and 100 mg A1(OH)₃ in saline. The immune response was estimated 2 weeks later as the serum IgG antibody titres against V67, β-lactoglobulin (β-LG) and α-lactalbumin (α-LA) using enzyme-linked immunosorbent assay (ELISA) and the tracheal Schulze-Dale response to these antigens. Feeding milk protein antigen to dams from birth and during pregnancy induces antigen-specific hyporesponsiveness (tolerance) in their offspring, despite no direct contact between the offspring and the milk proteins. Tolerance seems to be induced by the antigen itself since withdrawal of the MCD 10 days before delivery reduced tolerance in the offspring. No tolerance was produced in the offspring of dams fed the antigen from 3 months of age (adult). β-LG appears to be a major antigen in milk whey while α-LA is a minor one since there was almost no antibody or tracheal response to α-LA in any of the animals tested. The results indicate that maternal antigen experience and antigens present during pregnancy are important for the subsequent immune response to these antigens in offspring.