title: Biochemical nature and topographic localization of epitopes defining four distinct CD45 antigen specificities. Conventional CD45, CD45R, 180 kDa (UCHL1) and 220/205/190 kDa.
abstract: The biochemical nature and relative topographic localization of Ag determinants recognized on CD45 molecular complex by mAb defining four distinct Ag specificities (conventional CD45, CD45R, 180 kDa and 220/205/190 kDa) have been investigated. These Ag specificities display a differential biochemical, cellular, and histochemical distributions and are important in the definition of CD4-positive complementary functional T cell subsets and/or distinct stages of thymic maturation. Protease treatment of either CD45-positive cells or purified CD45 molecules revealed that both conventional CD45 and 180-kDa (UCHL1 epitope) Ag specificities are defined by epitopes present on a protease-resistant domain which is internal to the protease-sensitive epitopes defining both CD45R and 220/205/190-kDa Ag specificities. In addition, it is shown that carbohydrate moieties are contributing to the epitopes recognized by both the anti-180-kDa UCHL1 and the anti-220/205/190-kDa mAb. Neuraminidase treatment, which cleaves sialic acids either from N- or O-linked oligosaccharides, abrogated the reactivity of both mAb. However, N-glycanase treatment, which selectively cleaves N-linked sugars, did not affect the recognition of these two epitopes. Thus, these results demonstrate that the Ag determinants recognized by the UCHL1 and the anti-220/205/190-kDa mAb, which are topographically unrelated, are associated with sialic acids from O-linked-type oligosaccharides, emphasizing the contribution of carbohydrates to the Ag heterogeneity of CD45 molecular complex.
authors: Servicio de Inmunología, Universidad Autónoma, Madrid, Spain.
authors: R
authors: R
authors: Pulido
authors: F
authors: F
authors: Sánchez-Madrid
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D000937:Antigen-Antibody Reactions; D000943:Antigens, Differentiation / Q000276:immunology / Q000302:isolation & purification*; D002236:Carbohydrate Conformation; D000939:Epitopes / Q000276:immunology / Q000302:isolation & purification*; D006649:Histocompatibility Antigens / Q000276:immunology / Q000302:isolation & purification*; D006868:Hydrolysis; D017493:Leukocyte Common Antigens; D051379:Mice; D008970:Molecular Weight; D009844:Oligosaccharides; D010447:Peptide Hydrolases; D012794:Sialic Acids; D013329:Structure-Activity Relationship
chemical_list: D000911:Antibodies, Monoclonal; D000943:Antigens, Differentiation; D000939:Epitopes; D006649:Histocompatibility Antigens; D009844:Oligosaccharides; D012794:Sialic Acids; D017493:Leukocyte Common Antigens; D010447:Peptide Hydrolases