Lymphocyte function-associated antigen 1 (LFA-1) contains sulfated N-linked oligosaccharides.
The murine lymphocyte function-associated antigen 1 (LFA-1) is a glycoprotein heterodimer consisting of an Mr 180,000 alpha-chain and an Mr 95,000 beta-chain. Although LFA-1 has been studied extensively in the past few years due to its involvement in various antigen-specific T lymphocyte responses, virtually nothing is known about its glycosylation. In this report, we have analyzed the oligosaccharide moieties of the murine LFA-1 molecule. Utilizing a T lymphoma cell line, EL-4, it was found that [35S] sulfate, [3H]glucosamine, [3H]mannose, and [3H]fucose were incorporated into both the alpha- and beta-chains of LFA-1. Isolated alpha- and beta-chains from anti-LFA-1 immunoprecipitates of [3H]glucosamine-labeled NP-40 lysates were subjected to tryptic-chymotryptic digestion, and the resulting glycopeptides were fractionated by reverse-phase high performance liquid chromatography. Five major [3H]glucosamine-labeled glycopeptides were generated by this procedure from each of the two polypeptide chains. Treatment of the individual glycopeptides with almond emulsin peptide:N-glycosidase or Endo F demonstrated that the [3H]glucosamine label existed almost entirely in N-linked oligosaccharide structures (Mr 5000 to 10,000). By using similar techniques, the majority of the [35S]sulfate moieties were also found covalently bound to N-linked oligosaccharides. In addition, both [35S]sulfate-labeled alpha- and beta-chains were susceptible to Keratanase and endo-beta-galactosidase digestions, indicating the presence of sulfated N-acetyllactosamine sequences. The expression of [35S]sulfate-labeled LFA-1 on various cell types was also examined. LFA-1 was found to be sulfated only on thymocytes and splenic T cells, but not on macrophages, splenic B, or bone marrow cells.
D000818:Animals; D000911:Antibodies, Monoclonal; D000954:Antigens, Surface / Q000032:analysis / Q000276:immunology; D002236:Carbohydrate Conformation; D002851:Chromatography, High Pressure Liquid; D016169:Lymphocyte Function-Associated Antigen-1; D008715:Methionine / Q000378:metabolism; D051379:Mice; D008809:Mice, Inbred C3H; D008970:Molecular Weight; D009844:Oligosaccharides / Q000276:immunology; D051381:Rats; D011919:Rats, Inbred Strains; D013431:Sulfates / Q000378:metabolism; D014018:Tissue Distribution
D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D016169:Lymphocyte Function-Associated Antigen-1; D009844:Oligosaccharides; D013431:Sulfates; D008715:Methionine