Molecular weight and charge heterogeneity of Thy-1 glycoprotein in different populations of T-cells

• Published in: Molecular immunology Vol. 21; no. 5; p. 405
• Main Authors: Morrison, M H, Chaney, W G, Esselman, W J
• Format: Journal Article
• Language: English
• Published: England 01.05.1984
• Subjects: Animals; Antigens, Surface - immunology; Cells, Cultured; Chemical Precipitation; Electrophoresis, Polyacrylamide Gel; Flow Cytometry; Glycoside Hydrolases; Mice; Mice, Inbred C3H; Molecular Weight; N-Acetylneuraminic Acid; Peptide Fragments - analysis; Rabbits; Sialic Acids - analysis; T-Lymphocytes - immunology; Thy-1 Antigens
• ISSN: 0161-5890; 1872-9142
• DOI: 10.1016/0161-5890(84)90038-5

Molecular weight and charge microheterogeneity of Thy-1 glycoprotein expressed on different T-cell populations were compared by two-dimensional gel electrophoresis and endoglycosidase treatment. Thy-1 was immunoprecipitated from detergent lysates of radioiodinated T-cells of spleens, lymph nodes, Peyer's patches, peripheral blood, IL-2-cultured thymocytes and peanut agglutinin (PNA) separated thymocytes. In general, thymocytes and IL-2-cultured thymocytes expressed the highest levels of Thy-1 with a large Mr and charge variation. The Thy-1 of these cells was basic and contained low levels of sialic acid. On the other hand, peripheral T-lymphocytes exhibited a restricted Mr and more limited charge heterogeneity with higher amounts of sialic acid. The Thy-1 glycoprotein of mature, low Thy-1 PNA- thymocytes had Mr and charge heterogeneity identical to peripheral T-lymphocytes. The Mr and charge variation of immature PNA+ thymocytes was essentially identical to that of whole thymocytes. The molecular source of Mr heterogeneity in thymocyte Thy-1 and restricted Mr in lymph node Thy-1 was studied by analysis with endoglycosidase-H (Endo-H) and Endo-D. The results of Endo-H digestion showed that most of the Thy-1 polypeptides from both thymocyte and lymph node contained one high-mannose type oligosaccharide which was relatively small and not heterogeneous with respect to Mr. The complex-type oligosaccharides (Endo-D-sensitive) were larger and were responsible for the broad Mr-heterogeneity found in thymocyte Thy-1. Both thymocyte and lymph node Thy-1 generally appear to contain three N-linked oligosaccharides (one high-mannose and two complex) and sequential hydrolysis with Endo-H and Endo-D resulted in an unglycosylated polypeptide with an Mr of approx. 12,500.