title: Neuraminidase- and trypsin-induced exposure to membrane receptors for IgG and IgM molecules on human peripheral blood lymphocytes.
abstract: Brief incubation of human peripheral blood lymphocytes with vibrio cholerae neuraminidase (VCN) or trypsin revealed hidden membrane receptors for IgG and IgM molecules. The hidden receptors were found on T lymphocytes as shown by double-label and mixed rosetting experiments and by studies of T-enriched populations. Although IgM receptors were undetectable on freshly isolated lymphocytes, a mean of 17.1% of VCN-treated lymphocytes rosetted with ox erythrocytes coated with IgM antibody (EA-IgM). Prior to trypsin treatment a mean of 14.6% of human T lymphocytes rosetted with ox red cells coated with IgG antibody (EA-IgG). After incubation with trypsin this figure increased significantly (P less than 0.005) to 44.5%. VCN-treatment also significantly increased (P less than 0.005) the mean percentage of EA-IgG rosette-forming T cells to 38.5%. The T-cell receptor for IgG was shown to be trypsin-resistant while the IgM receptor was shown to be trypsin-sensitive. Using mixed rosettes, a tentative T-cell subset was identified which expressed both IgG and IgM membrane receptors. Also, a minor subset with IgM receptors alone and a larger subset with only IgG receptors were identified.
mesh_terms: D001666:Binding Sites, Antibody; D002462:Cell Membrane / Q000276:immunology; D006801:Humans; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D008214:Lymphocytes / Q000276:immunology*; D009439:Neuraminidase; D012397:Rosette Formation; D013601:T-Lymphocytes / Q000276:immunology; D014357:Trypsin
chemical_list: D007074:Immunoglobulin G; D007075:Immunoglobulin M; D009439:Neuraminidase; D014357:Trypsin