title: A novel T cell activation antigen identified by monoclonal IMN3.1 antibody and expressed preferentially on human T cells susceptible to apoptotic cell death.
abstract: When cultured without appropriate growth factors, most of activated (CD45RO+) T cells expanded in acute EBV-induced infectious mononucleosis (IM) easily die via an apoptotic cell death mechanism, indicating one Ag-driven selection in the periphery. In this work, we attempted to raise the mAb against cell surface molecules, preferentially expressed on T cells entering apoptosis, by immunizing PBMC from an acute IM patient. We obtained one mAb, termed IMN3.1, that could define clearly the expansion of activated (CD45RO+) T cells in the blood of acute IM patients. In contrast to its intense expression on IM T cells, the IMN3.1-reactive Ag was only dimly expressed on CD45RO+ (memory or previously activated) populations of T cells from normal individuals. Although naive (CD45RO-) populations of T cells usually lacked IMN3.1 Ag, this Ag was inducible relatively late after in vitro activation of naive T cells. The cellular distribution and molecular characterization of IMN3.1-reactive Ag suggested that IMN3.1 mAb appeared to recognize a novel activation-associated cell surface determinant of about 120 kDa m.w., which might be predominantly expressed on apoptosis-prone T cell lineage cells, such as IM T cells, thymocytes, cytokine-dependent T cell lines, and anti-Fas-sensitive T cell lines.
authors.affiliation: Department of Pediatrics, School of Medicine, Kanazawa University, Ishikawa, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Uehara
authors.forename: T
authors.initials: T
authors.lastname: Miyawaki
authors.forename: S
authors.initials: S
authors.lastname: Natsuume-Sakai
authors.forename: R
authors.initials: R
authors.lastname: Nibu
authors.forename: M
authors.initials: M
authors.lastname: Hasui
authors.forename: A
authors.initials: A
authors.lastname: Yachie
authors.forename: S
authors.initials: S
authors.lastname: Shimizu
authors.forename: N
authors.initials: N
authors.lastname: Taniguchi
mesh_terms: D000328:Adult; D000818:Animals; D000911:Antibodies, Monoclonal / Q000096:biosynthesis / Q000276:immunology*; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis* / Q000276:immunology; D000954:Antigens, Surface / Q000032:analysis / Q000276:immunology; D017209:Apoptosis; D002460:Cell Line; D002648:Child; D005455:Fluorescent Antibody Technique; D006801:Humans; D007231:Infant, Newborn; D017493:Leukocyte Common Antigens / Q000032:analysis; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D013601:T-Lymphocytes / Q000276:immunology* / Q000502:physiology; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7; D019014:fas Receptor
chemical_list: D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7; D019014:fas Receptor; D017493:Leukocyte Common Antigens