Molecular weight analysis of cow's milk antigens in neonate sera

Some food antigens (Ag) can be detected in serum immunoglobulin G (IgG) antibodies (Ab) following ingestion. These Ag may thus be essential for inducing the production of IgE or IgG antibodies, which may in turn lead to the onset of atopic diseases such as atopic dermatitis, allergic rhinitis and asthma. The molecular weights (MW) of these Ag have yet to be determined. To select samples for MW analysis of circulating food Ag, we measured the concentrations of cow's milk (CM) Ag in the sera of 88 neonates by radio-immunoassay. They were found present in 20 samples of the sera. Twelve of the samples were analyzed for Ag MW by immunoblotting. Several bands appeared for one of the samples. Their MW were < 13,000 and no native CM proteins could be detected.