Specific high-affinity binding sites for a synthetic gliadin heptapeptide of human peripheral blood lymphocytes

The synthetic peptide containing residues 43-49 of α-gliadin, the major protein component of gluten, has previously been shown to inhibit the production of lymphokine activities by mononuclear leukocytes. The authors demonstrate using radiolabeled α-gliadin(43-49) that human peripheral blood lymphocytes express approximately 20,000-25,000 surface receptors for this peptide, with a dissociation constant (K/sub D/) of 20 nM. In addition, binding is inhibited by naloxone and an enkephalin analog, thus confirming the functional correlate which demonstrates inhibition by these agents of α-gliadin(43-49) functional effects. Furthermore, B-lymphocytes bind specifically a greater amount of [125I]α-gliadin(43-49) than T-lymphocytes. The lymphocyte α-gliadin(43-49) receptor may play an important role in mediating the immunological response to α-gliadin. 16 references, 4 figures