title: B220 is expressed on apoptotic thymocytes induced by X-irradiation.
abstract: CD45 is cell surface glycoprotein and expressed on all haematopoietic cells except mature erythrocytes and platelets. Eight isoforms of CD45 are generated by alternative splicing of exons 4-6. B220 including all three exons is expressed specifically on pan-B cell lineage. Recently, it was reported that B220 was expressed on apoptotic T cells induced by staphylococcal enterotoxin B (SEB). In the present study, we investigated the expression of B220 on murine thymocytes after whole-body X-irradiation. We used the forward light scattering of flow cytometry as a parameter of cell size, and defined two populations; FSChigh (normal cell size) and FSClow (correspond to apoptotic cell in size) fraction. B220+ cells in FSChigh fraction reached a maximum value (35%) at 18 hr after irradiation. In FSClow fraction, 40-60% cells were positive for B220 at any time points. These results suggest that B220 is expressed on thymocytes in the pre-apoptotic stage, because B220 was expressed on not only FSClow cells but also FSChigh cells.
authors.affiliation: Department of Veterinary Medicine, College of Agriculture, Osaka Prefecture University, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Oka
authors.forename: K
authors.initials: K
authors.lastname: Kubo
authors.forename: S
authors.initials: S
authors.lastname: Matsuyama
authors.forename: Y
authors.initials: Y
authors.lastname: Takamori
mesh_terms: D000818:Animals; D017209:Apoptosis; D004247:DNA / Q000032:analysis; D004587:Electrophoresis, Agar Gel; D005434:Flow Cytometry; D017493:Leukocyte Common Antigens / Q000096:biosynthesis*; D051379:Mice; D008811:Mice, Inbred DBA; D013601:T-Lymphocytes / Q000378:metabolism / Q000528:radiation effects*; D014916:Whole-Body Irradiation
chemical_list: D004247:DNA; D017493:Leukocyte Common Antigens