RECOMBINANT PROTEINS IN NEWLY DEVELOPED FOODS - IDENTIFICATION OF ALLERGENIC ACTIVITY

A number of agricultural crops are being modified for various purposes using recombinant DNA technology. Since transferred genes may code fo r proteins that an ordinarily not present, there is concern about the potential allergenicity of these new varieties. The safety evaluation of transgenic foods is relatively easy when the allergenicity of the g ene source is known. Recombinant allergens in genetically engineered o r altered foods can be identified using traditional immunological assa ys such as RAST or ELISA inhibition or immunoblotting procedures, Our recent studies of two corn proteins (10 kD and HSZ) used to alter grai n amino acid composition and of transgenic soybeans with an altered fa tty acid profile are examples of this approach, Both 10 kD and HSZ did not bind IgE antibodies from sera of corn-reactive subjects by immuno blotting. Studies of wild-type and transgenic soybeans with high oleic acidic content by RAST inhibition and immunoblotting with pooled sera of soy-allergic individuals demonstrated no difference in the allerge n content of both extracts. In contrast to these studies, a recent inv estigation by Nordlee et al. (1996) of transgenic soybeans which expre ssed a methionine/cysteine-rich protein from Brazil nuts identified th is protein as a major Brazil nut allergen, These studies indicate that , when the gene source is from a known allergen or if the recipient co ntains allergens, it is possible to determine whether the allergen con tent of the transgenic line is altered relative to the nontransgenic v arieties.