A Novel CD8 T Cell-Restricted CD45RB Epitope Shared by CD43 Is Differentially Affected by Glycosylation

• Published in: The Journal of immunology (1950) 1999-08, Vol.163 (3), p.1441-1448
• Main Authors: Carlow, Douglas A, Ardman, Blair, Ziltener, Hermann J
• Format: Article
• Language: English
• Subjects: AIDS/HIV; Animals; Antibodies, Monoclonal - metabolism; Antigens, CD; Binding Sites, Antibody; CD8-Positive T-Lymphocytes - immunology; CD8-Positive T-Lymphocytes - metabolism; Epitopes, T-Lymphocyte - biosynthesis; Epitopes, T-Lymphocyte - immunology; Epitopes, T-Lymphocyte - metabolism; Exons - immunology; Glycosylation; Leukocyte Common Antigens - biosynthesis; Leukocyte Common Antigens - genetics; Leukocyte Common Antigens - immunology; Leukocyte Common Antigens - metabolism; Leukosialin; Lymph Nodes - cytology; Lymph Nodes - immunology; Lymph Nodes - metabolism; Mice; Mice, Inbred BALB C; Molecular Weight; N-Acetylglucosaminyltransferases - deficiency; N-Acetylglucosaminyltransferases - genetics; N-Acetylglucosaminyltransferases - metabolism; N-Acetylneuraminic Acid - metabolism; Neuraminidase - metabolism; Precipitin Tests; Protein Isoforms - biosynthesis; Protein Isoforms - genetics; Protein Isoforms - immunology; Protein Isoforms - metabolism; Sialoglycoproteins - immunology; Sialoglycoproteins - metabolism; Thymoma - immunology; Thymoma - metabolism; Tumor Cells, Cultured
• ISSN: 0022-1767; 1550-6606
• DOI: 10.4049/jimmunol.163.3.1441

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.