B220 is Expressed on Apoptotic Thymocytes Induced by X-Irradiation.

• DOI: 10.1292/jvms.61.337
• Publication Date: 2002-10-09T03:07:09Z
• Authors: Shuntaro Oka; Kihei Kubo; Satoshi Matsuyama; Yasuhiko Takamori
• Keywords: Electrophoresis, Agar Gel; T-Lymphocytes; Apoptosis; DNA; Flow Cytometry; Mice; 03 medical and health sciences; 0302 clinical medicine; Mice, Inbred DBA; Animals; Leukocyte Common Antigens; Whole-Body Irradiation

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.