Food antigens ingested by the mother can sensitize the offspring via the mother, though how the child's immune system responds to them is poorly understood. This is because mothers also can produce antibodies to ingested food antigens that can be transferred to the child, and it is difficult to distinguish between such maternal antibodies and antibodies produced by the child's immune system in response to maternal antigens. In this study, we examined the effects of antigens ingested by pregnant and lactating mothers on the immune responses of their offspring using DO11.10, introducing a T cell receptor gene that recognizes the ovalbumin peptide. Since DO11.10, unlike wild-type mice, is strongly sensitized even by oral administration of ovalbumin alone, we have successfully induced allergic predisposition in DO11.10 by oral administration of ovalbumin in the past. Hence, we used the combination of a wild-type mother and DO11.10 heterozygous offspring to investigate the effects of mother-derived antigens on the offspring's immune system while minimizing the mother's immune response. We found that antigen-specific antibodies in the sera of offspring of mothers which ingested antigens during pregnancy and lactation and the class of antibodies in the offspring depended on the antigen ingestion by the mother. Furthermore, offspring from mothers which received continuous oral antigen ingestion during lactation had higher levels of serum antigen-specific IgE induced by sensitization after growth than those of mothers which did not ingest the antigen. In contrast, when the offspring of allergic DO11.10 mothers were given the same antigen orally after maturation, antibody titers did not differ significantly from those of offspring of non-allergic DO11.10 mothers. These results suggest that the antigen ingestion by the mother during pregnancy and lactation affects the immune response of their offspring.