A novel CD8 T cell-restricted CD45RB epitope shared by CD43 is differentially affected by glycosylation.
The mAb 1B11 has been characterized as recognizing the activation-associated glycoform of murine CD43, a heavily O-glycosylated protein implicated in leukocyte homing. When hemopoietic cells from CD43-/- mice were stained with 1B11, CD43-independent binding of 1B11 was observed on peripheral CD8 T cells and at low levels on thymocytes, while no binding was detected on CD4 T cells, B cells, or bone marrow cells. Levels of 1B11 staining were comparable in lymph node CD8+ T cells from both CD43-/- mice and CD43+/+ mice. We sought to identify the CD43-independent target of 1B11 expressed on CD8 T cells. Previous work had demonstrated that neuraminidase treatment of lymph node cells (LNC) enhanced 1B11 binding on CD43+/+ LNC; this enhancement was also observed in CD43-/- LNC. We show that neuraminidase-enhanced 1B11 binding in CD43-/- LNC and EL4 thymoma cells is CD43 independent and that 1B11 detects a novel target of apparent mass of approximately 200 kDa identified as a hyposialylated form of CD45RB preferentially expressed on peripheral CD8, but not CD4, T cells. Our data also show that the recognition of CD43 and CD45RB by 1B11 is differentially affected by O-linked glycosylation and sialic acid. Whereas 1B11 recognition of CD43 on activated T cells required both core 2 O-glycan branching and sialic acid, 1B11 recognition of CD45 only occurred in the absence of both core 2 glycosylation and sialic acid.
The Biomedical Research Centre, University of British Columbia, Vancouver, Canada.
D A
DA
Carlow
B
B
Ardman
H J
HJ
Ziltener
D000818:Animals; D000911:Antibodies, Monoclonal / Q000378:metabolism; D015703:Antigens, CD; D001666:Binding Sites, Antibody; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D018984:Epitopes, T-Lymphocyte / Q000096:biosynthesis / Q000276:immunology / Q000378:metabolism*; D005091:Exons / Q000276:immunology; D006031:Glycosylation; D017493:Leukocyte Common Antigens / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D051917:Leukosialin; D008198:Lymph Nodes / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D008970:Molecular Weight; D017351:N-Acetylglucosaminyltransferases / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D019158:N-Acetylneuraminic Acid / Q000378:metabolism; D009439:Neuraminidase / Q000378:metabolism; D011233:Precipitin Tests; D020033:Protein Isoforms / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D012795:Sialoglycoproteins / Q000276:immunology / Q000378:metabolism*; D013945:Thymoma / Q000276:immunology / Q000378:metabolism; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D018984:Epitopes, T-Lymphocyte; D051917:Leukosialin; D020033:Protein Isoforms; D012795:Sialoglycoproteins; C497863:Spn protein, mouse; D017351:N-Acetylglucosaminyltransferases; C066287:UDP-GlcNAc-Gb(5)Cer beta1-6N-acetylglucosaminyltransferase; D017493:Leukocyte Common Antigens; D009439:Neuraminidase; D019158:N-Acetylneuraminic Acid