Inhibition of IgE binding to tissue culture cells and leucocytes by pentapeptide.
The specific binding of radiolabelled IgE to a tissue culture lymphoblastoid cell line (Wil-2WT) was confirmed. The binding of IgE and Hamburger's IgE-derived pentapeptide Asp-Ser-Asp-Pro-Arg (HEPP) to Wil-2WT cells and to human leucocytes was compared. HEPP inhibition of IgE binding to leucocytes averaged 24% but with Wil-2WT cells only 12% inhibition was observed with double the amount of HEPP. Using myeloma IgE to inhibit the binding of tritiated HEPP to leucocytes and Wil-2WT cells confirmed the specificity of the peptide binding as well as the greater affinity of HEPP for leucocytes (basophils) compared to Wil-2WT lymphoblastoid cells. Based upon the extent of binding and the maximum inhibition attainable with HEPP it is suggested that the receptors for IgE on Wil-2WT cells, basophilic leucocytes and mast cells are not identical but that they share specificities in common. A new hypothesis for the mechanism of action of HEPP is proposed.
D001491:Basophils / Q000276:immunology; D001667:Binding, Competitive; D002460:Cell Line; D003429:Cross Reactions; D006801:Humans; D007073:Immunoglobulin E / Q000037:antagonists & inhibitors / Q000378:metabolism*; D007962:Leukocytes / Q000276:immunology*; D008168:Lung / Q000276:immunology; D008407:Mast Cells / Q000276:immunology; D009842:Oligopeptides / Q000494:pharmacology*; D012867:Skin / Q000276:immunology
D009842:Oligopeptides; D007073:Immunoglobulin E