title: Der p I, a major allergen of the house dust mite, proteolytically cleaves the low-affinity receptor for human IgE (CD23).
abstract: The nature of the proteases that cleave CD23 in vivo is of considerable interest, but remains unknown. Here, we demonstrate that Der p I, a major allergen of the house dust mite Dermatophagoides pteronyssinus, cleaves CD23 from the surface of cultured human B cells (RPMI 8866 B cell line). The cleavage of the receptor from the B cell surface was associated with a parallel increase in soluble CD23 (sCD23) in the culture supernatant. Furthermore, the proteolytic effect of Der p I was specific for CD23, since none of the other B cell markers tested (CD20, HLA-DR, CD71 and CD49d) were affected. Labeled antibody experiments and protease inhibition assays clearly demonstrate that Der p I is a cysteine protease that directly cleaves a 25-kDa fragment of CD23. These data suggest that the cysteine protease Der p I, in addition to being highly immunogenic, may up-regulate IgE synthesis by virtue of its ability to cleave CD23.
mesh_terms: D000485:Allergens / Q000494:pharmacology*; D000595:Amino Acid Sequence; D000818:Animals; D039741:Antigens, Dermatophagoides; D001402:B-Lymphocytes / Q000187:drug effects / Q000276:immunology*; D002478:Cells, Cultured; D003546:Cysteine Endopeptidases / Q000494:pharmacology*; D006023:Glycoproteins / Q000494:pharmacology*; D006801:Humans; D008925:Mites; D008969:Molecular Sequence Data; D017455:Receptors, IgE / Q000032:analysis / Q000378:metabolism*
chemical_list: D000485:Allergens; D039741:Antigens, Dermatophagoides; D006023:Glycoproteins; D017455:Receptors, IgE; D003546:Cysteine Endopeptidases