title: Effect of tunicamycin on the assembly and antigenicity of HLA antigens: analysis with monoclonal antibodies.
abstract: The effect of glycosylation on the assembly and antigenicity of HLA antigens was investigated by examining HLA antigens synthesized in the presence of the antibiotic tunicamycin, an inhibitor of asparagine-linked oligosaccharide addition, with monoclonal antibodies specific for a variety of antigenic determinants. The monoclonal antibody Q5/13 reactive with a determinant expressed on the beta chain of human Ia-like antigens immunoprecipitated alpha and beta subunits with reduced apparent molecular weights from tunicamycin-treated cells, indicating that glycosylation is not required for association of the Ia-like antigen alpha and beta subunits. Immunoprecipitation of HLA-A,B,C antigens from tunicamycin-treated cells with four monoclonal antibodies specific for the heavy chain and one specific for beta 2-microglobulin showed that the heavy-chain determinant detected by the antibody Q6/64 is absent from the non-glycosylated molecule. This is the first demonstration that carbohydrate addition during biosynthesis affects the protein conformation of the HLA-A,B,C heavy chain.
mesh_terms: D000911:Antibodies, Monoclonal; D050260:Carbohydrate Metabolism; D011232:Chemical Precipitation; D000939:Epitopes; D005944:Glucosamine / Q000031:analogs & derivatives*; D006680:HLA Antigens; D000949:Histocompatibility Antigens Class II; D006801:Humans; D008970:Molecular Weight; D011487:Protein Conformation / Q000187:drug effects; D014415:Tunicamycin / Q000494:pharmacology*
chemical_list: D000911:Antibodies, Monoclonal; D000939:Epitopes; D006680:HLA Antigens; D000949:Histocompatibility Antigens Class II; D014415:Tunicamycin; D005944:Glucosamine