Surfaces of murine lymphocyte subsets differ in sialylation states and antigen distribution of a major N-linked penultimate saccharide structure.
Rat liver beta-galactoside alpha-2,6-sialyltransferase and Vibrio cholerae sialidase were used with cytidine-5'-monophospho-N-acetyl-[3H]neuraminic acid (CMP-[3H]NeuAc) to specifically probe the distribution and sialylation state of Gal beta 1-4GlcNAc residues on N-linked saccharides on the surfaces of murine lymphocytes. The relative extent of exogenous sialyltransferase-mediated sialylation (per cellular protein) was thymocytes greater than T-cells greater than T-cell lymphoma (EL-4) greater than B-cells greater than B-cell lymphoma (AKTB-1b) greater than splenocytes. Prior desialylation increased exogenous resialylation by 23.8-, 13.1-, 7.1-, 7.9-, 7.0-, and 5.3-fold for splenocytes, B-cells, T-cells, EL-4, AKTB-1b, and thymocytes, respectively. Though numerous glycoproteins were labeled, the majority of the Gal beta 1-4GlcNAc residues were detected on a relatively small number of cell surface proteins, many of which are well-defined lymphocyte antigens. Gal beta 1-4GlcNAc residues on thymocytes were found to exist in an undersialylated state on T200 but not on other antigens (e.g., Thy-1). T200 was found to be fully sialylated on mature cells (i.e., hydrocortisone-resistant thymocytes and splenic T-cells), suggesting that its sialylation state is developmentally regulated. These studies indicate that the number, sialylation state, and polypeptide distribution of the penultimate structure, Gal beta 1-4GlcNAc, differ on N-linked saccharides on the surfaces of different lymphocyte populations.
Whiteheart
S W
SW
Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.
McLenithan
J C
JC
Hart
G W
GW
D000818:Animals; D000943:Antigens, Differentiation / Q000032:analysis; D000954:Antigens, Surface / Q000032:analysis*; D004591:Electrophoresis, Polyacrylamide Gel; D006001:Glycoconjugates / Q000032:analysis; D006649:Histocompatibility Antigens / Q000032:analysis; D017493:Leukocyte Common Antigens; D008214:Lymphocytes / Q000032:analysis* / Q000276:immunology; D051379:Mice; D008809:Mice, Inbred C3H; D019158:N-Acetylneuraminic Acid; D009844:Oligosaccharides / Q000378:metabolism*; D012794:Sialic Acids / Q000378:metabolism*; D012799:Sialyltransferases / Q000494:pharmacology
D000943:Antigens, Differentiation; D000954:Antigens, Surface; D006001:Glycoconjugates; D006649:Histocompatibility Antigens; D009844:Oligosaccharides; D012794:Sialic Acids; D012799:Sialyltransferases; D017493:Leukocyte Common Antigens; D019158:N-Acetylneuraminic Acid