title: Enhancement of B7-1 (CD80) expression on B-lymphoma cells by irradiation.
abstract: Irradiation of A20.2J mouse B-lymphoma cells enhanced their antigen-presenting ability to induce interleukin-2 (IL-2) production by 42-6A T cells specific for ovalbumin (OVA)323-339/I-Ad. Irradiated and fixed A20.2J cells were more efficient antigen-presenting cells (APC) to present OVA323-339 peptide than the unirradiated and fixed cells. Irradiation selectively increased the expression of B7-1 molecules, but not of the major histocompatibility complex class II molecules, B7-2, lymphocyte function-associated antigen-1, or intracellular adhesion molecule-1. Irradiation of A20.2J cells with 100 Gy followed by overnight incubation was optimal for the enhancement of B7-1 expression. Anti-B7-1 monoclonal antibody inhibited the irradiation-induced enhancement of APC function. Irradiation of A20.2J cells induced the accumulation of B7-1 mRNA. Thus, it was concluded that the enhancement of APC function by irradiation was due to the up-regulation of B7-1 molecules through the accumulation of its mRNA. Although partial inhibition of protein synthesis has been shown to enhance the accumulation of B7-1 mRNA and its expression, irradiation did not decrease the protein synthesis in A20.2J cells. The incubation with irradiated A20.2J cells stimulated unirradiated A20.2J cells to increase B7-1 expression, suggesting that irradiation of A20.2J cells induced expression or secretion of some molecule(s) to enhance B7-1 expression.
authors.affiliation: First Department of Surgery, University School of Medicine, 5-21-16 Omori-nishi, Ota-ku, Tokyo, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Seo
authors.forename: F
authors.initials: F
authors.lastname: Ishikawa
authors.forename: H
authors.initials: H
authors.lastname: Nakano
authors.forename: H
authors.initials: H
authors.lastname: Nakazaki
authors.forename: K
authors.initials: K
authors.lastname: Kobayashi
authors.forename: T
authors.initials: T
authors.lastname: Kakiuchi
mesh_terms: D000818:Animals; D017951:Antigen Presentation / Q000528:radiation effects*; D000951:Antigens, Neoplasm / Q000235:genetics / Q000378:metabolism*; D018122:B7-1 Antigen / Q000235:genetics / Q000378:metabolism*; D015152:Blotting, Northern; D004307:Dose-Response Relationship, Radiation; D007376:Interleukin-2 / Q000096:biosynthesis; D016393:Lymphoma, B-Cell / Q000276:immunology*; D051379:Mice; D012333:RNA, Messenger / Q000235:genetics; D012334:RNA, Neoplasm / Q000235:genetics; D014407:Tumor Cells, Cultured; D015854:Up-Regulation / Q000528:radiation effects
chemical_list: D000951:Antigens, Neoplasm; D018122:B7-1 Antigen; D007376:Interleukin-2; D012333:RNA, Messenger; D012334:RNA, Neoplasm