NEURAMINIDASE-INDUCED AND TRYPSIN-INDUCED EXPOSURE OF MEMBRANE RECEPTORS FOR IGG AND IGM MOLECULES ON HUMAN PERIPHERAL-BLOOD LYMPHOCYTES

  • 1 January 1977
    • journal article
    • research article
    • Vol. 29  (3) , 457-463
Abstract
Brief incubation of human peripheral blood lymphocytes with Vibrio cholerae neuraminidase (VCN) or trypsin revealed hidden membrane receptors for Ig[immunoglobulin]G and IgM molecules. The hidden receptors were found on T [thymus derived] 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[erythrocyte antigen]-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 < 0.005) to 44.5%. VCN-treatment also significantly increased (P < 0.005) the mean percentage of EA-IgG rosette-forming T cells to 38.5%. The T-cell receptor for IgG was trypsin-resistant while the IgM receptor was trypsin-sensitive. Using mixed rosettes, a tentative T-cell subset was identified which expressed both IgG and IgM membrane receptors. A minor subset with IgM receptors alone and a larger subset with only IgG receptors were identified.