Specific high-affinity binding sites for a synthetic gliadin heptapeptide on human peripheral blood lymphocytes.
The synthetic peptide containing residues 43-49 of alpha-gliadin, the major protein component of gluten, has previously been shown to inhibit the production of lymphokine activities by mononuclear leukocytes. We now demonstrate using radiolabeled alpha-gliadin(43-49) that human peripheral blood lymphocytes express approximately 20,000-25,000 surface receptors for this peptide, with a dissociation constant (KD) 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 alpha-gliadin(43-49) functional effects. Furthermore, B-lymphocytes bind specifically a greater amount of [125I]alpha-gliadin(43-49) than T-lymphocytes. The lymphocyte alpha-gliadin(43-49) receptor may play an important role in mediating the immunological response to alpha-gliadin.
D001665:Binding Sites; D001773:Blood Cells / Q000378:metabolism*; D005903:Gliadin / Q000097:blood*; D006706:Homeostasis; D006801:Humans; D007457:Iodine Radioisotopes; D008214:Lymphocytes / Q000378:metabolism* / Q000648:ultrastructure; D010446:Peptide Fragments / Q000097:blood*; D010940:Plant Proteins / Q000097:blood*; D013329:Structure-Activity Relationship
D007457:Iodine Radioisotopes; D010446:Peptide Fragments; D010940:Plant Proteins; C051588:alpha-gliadin (43-49); D005903:Gliadin