B cell surface glycoprotein induced during growth response: molecular structure and expression pattern.
We present the molecular characterization of a cell surface antigen, B 7.2, that is expressed on activated B lymphocytes. The BCL1 and CH12 B lymphoma cells express the B 7.2 antigen constitutively. In small resting B cells from spleen, the B 7.2 expression is induced during polyclonal growth in response to mitogenic stimulation. B 7.2 expression also occurs with a significant frequency in cells from fresh lymphoid tissues. The endogenous expression of the B 7.2 antigen is high in spleen and lymph nodes, and is undetectable in the thymus. The B 7.2 antigen is a microheterogeneous 45,000 to 50,000 dalton glycoprotein with a single polypeptide chain, intramolecular S--S bonds, and N-linked glycan moieties. The folded structure of the B 7.2 antigen appears to contain a domain with hydrophilic properties exposed on the cell surface and a hydrophobic segment that may comprise a transmembrane portion. Considering the observed expression pattern and the molecular structure, we speculate that the B 7.2 antigen has a specific function in regulation of B cell activation, perhaps as a receptor for a regulatory ligand or as a ligand recognized by other B or T cells.
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000951:Antigens, Neoplasm / Q000096:biosynthesis / Q000302:isolation & purification; D001402:B-Lymphocytes / Q000276:immunology*; D005260:Female; D005347:Fibroblasts / Q000276:immunology; D006133:Growth Substances / Q000096:biosynthesis / Q000302:isolation & purification*; D015847:Interleukin-4; D008198:Lymph Nodes / Q000276:immunology; D008213:Lymphocyte Activation; D008222:Lymphokines / Q000096:biosynthesis / Q000302:isolation & purification*; D008223:Lymphoma / Q000276:immunology; D051379:Mice; D008815:Mice, Inbred Strains; D011487:Protein Conformation; D013154:Spleen / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology; D013950:Thymus Gland / Q000276:immunology
D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D006133:Growth Substances; D008222:Lymphokines; D015847:Interleukin-4