Alpha 2,3-linked sialic acids are more abundant in CD45 antigens and leukosialins of abnormal T cells of lpr mice than in those of normal T cells.
T cells from enlarged lymph nodes of MRL/MpJ-lpr/lpr (lpr) mice were found to express more binding sites for strongly hemagglutinating Phaseolus vulgaris agglutinin (PHA-E4) and fewer binding sites for Ricinus communis aglutinin (RCA) than those from normal MRL/MpJ-+/+ (+/+) mouse lymph node. We found that high-molecular-weight (180K-220K) glycoproteins on lpr T cells were strongly stained with these lectins on Western-blotting. These glycoproteins were found to belong to the CD45 family, by absorption with monoclonal anti-CD45 antibody. We also found that the other glycoproteins (105K and 120K glycoproteins on lpr T cells and a 105K glycoprotein on +/+ T cells) were strongly stained with the lectins which preferentially bind to mucin-type (O-linked) sugar chains on the cell surface. These glycoproteins were found to be leukosialins, by absorption with anti-leukosialin serum. From the results of the lectin-binding to these glycoproteins after sialidase treatment, CD45 antigens and leukosialin molecules on lpr T cells were found to have many more terminal alpha 2,3-linked sialic acids than those on +/+ T cells, and this fact explains why lpr T cells have more binding sites for PHA-E4 but fewer binding sites for RCA.
Yamashita
Y
Y
Division of Chemical Toxicology and Immunochemistry, Faculty of Pharmaceutical Sciences, University of Tokyo.
Imai
Y
Y
Osawa
T
T
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D015703:Antigens, CD; D000943:Antigens, Differentiation / Q000097:blood*; D006649:Histocompatibility Antigens / Q000097:blood*; D007106:Immune Sera / Q000276:immunology; D037102:Lectins / Q000276:immunology; D017493:Leukocyte Common Antigens; D051917:Leukosialin; D008180:Lupus Erythematosus, Systemic / Q000097:blood; D008562:Membrane Glycoproteins / Q000378:metabolism; D051379:Mice; D009439:Neuraminidase / Q000494:pharmacology; D012794:Sialic Acids / Q000097:blood*; D012795:Sialoglycoproteins / Q000097:blood*; D013601:T-Lymphocytes / Q000276:immunology*
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000943:Antigens, Differentiation; D006649:Histocompatibility Antigens; D007106:Immune Sera; D037102:Lectins; D051917:Leukosialin; D008562:Membrane Glycoproteins; D012794:Sialic Acids; D012795:Sialoglycoproteins; C497863:Spn protein, mouse; D017493:Leukocyte Common Antigens; D009439:Neuraminidase