Abstract
Female BALB/c mice were fed cow’s milk proteins. After sensitization with ovalbumin and alum, they were bred and fed egg white proteins during lactation. The pups breastfed by them were named Allergy-Egg (AE) group. As controls, Egg (E) group was breastfed by non-sensitized mothers fed egg white proteins during lactation, and Milk (M) group was breastfed by non-sensitized mothers fed milk proteins throughout the experiment. After sensitizing all the pups with ovalbumin and alum, diarrhea associated with experimental Th2 intestinal inflammation was tested by oral administration of ovalbumin. Diarrhea was suppressed in AE and E pups in comparison with M pups. Concomitantly, AE and E pups showed a low level of serum anti-ovalbumin IgE and suppression of ovalbumin-dependent IL-4 synthesis by spleen cells. Immune complexes of ovalbumin IgA and IgG1 were significantly increased in AE breast milk. Thus it was proved that oral tolerance was induced in the pups via breastfeeding even from allergic mothers as well as from non-allergic mothers. Immune complexes in breast milk are suggested to be involved in this process.
