Studies of in vitro gamma-interferon production in coeliac disease as a response to gliadin peptides.

The effects of certain fractions of a peptic-tryptic-pancreatinic (PTP) digest of wheat gliadin and of synthetic peptides on the production of gamma interferon (gamma-IFN) in cultures of whole blood from adult patients with coeliac disease (CD) have been studied using a sandwich enzyme immunoassay. The most active peptides were fraction 9, its two principal sub-fractions (sub-fractions 1 and 2) and a synthetic peptide of sequence RPQQPYPQPQPQ (peptide V) corresponding to the principal peptide obtained from reversed-phase HPLC of fraction 9. Results with blood from the control group of subjects also indicated some response to these antigens, in most cases at similar levels to those observed with the coeliacs. Fraction 1 of the PTP digest and the other nine synthetic peptides tested were inactive with both coeliacs and controls. These results are in agreement with the results of in vivo and in vitro toxicity tests. They provide evidence of a link between toxicity and cell-mediated immune response in CD, and suggest that peptide V represents one of the active parts of the gliadin molecule.