Irradiation up-regulates CD80 expression through induction of tumour necrosis factor-alpha and CD40 ligand expression on B lymphoma cells.
Previously, we reported that 100 Gy X-ray irradiation followed by 24 hr incubation up-regulates CD80 expression in murine B lymphoma cells, A20-2J. In the present study, we analysed the underlying mechanisms of such up-regulation using A20-HL cells derived from A20-2J cells. Irradiation of A20-HL cells with 100 Gy enhanced CD80 expression. Incubation of untreated A20-HL cells with those 100 Gy irradiated induced up-regulation of CD80 expression. Irradiation of A20-HL cells also up-regulated the expression of tumour necrosis factor-alpha (TNF-alpha) and CD40 ligand (CD40L), and the amount of immunoprecipitable TNF-alpha and CD40L in cell lysates. The addition of anti-TNF-alpha or anti-CD40L monoclonal antibody (mAb) to the incubation of irradiated A20-HL cells partially inhibited up-regulation of CD80 expression, and the addition of both antibodies together almost completely inhibited the up-regulation, suggesting that irradiation up-regulated the CD80 expression through the induction of TNF-alpha and CD40L expression. Irradiation also increased the accumulation of CD80, TNF-alpha and CD40L mRNA. n-tosyl-l-phenylalanine chloromethyl ketone (TPCK), a nuclear factor (NF)-kappaB inhibitor, markedly decreased irradiation-induced accumulation of CD80 mRNA and CD80 expression. FK506, a calcineurin inhibitor, and nifedipine, a calcium channel inhibitor, inhibited not only the expression of TNF-alpha and CD40L, but also the up-regulation of CD80 on irradiated A20-HL cells. These results strongly suggested that irradiation induced TNF-alpha and CD40L expression, which then up-regulated CD80 mRNA and CD80 expression through activation of NF-kappaB transcription factor in A20-HL cells.
Ishikawa
Fumio
F
Department of Immunology, Toho University School of Medicine, Tokyo, Japan.
Nakano
Hideki
H
Seo
Akira
A
Okada
Yayoi
Y
Torihata
Hideko
H
Tanaka
Yuriko
Y
Uchida
Tetsuya
T
Miyake
Hidekazu
H
Kakiuchi
Terutaka
T
D000818:Animals; D000951:Antigens, Neoplasm / Q000235:genetics / Q000276:immunology / Q000528:radiation effects*; D018122:B7-1 Antigen / Q000235:genetics / Q000276:immunology / Q000528:radiation effects*; D023201:CD40 Ligand / Q000276:immunology / Q000528:radiation effects; D003713:Dendritic Cells / Q000276:immunology; D016393:Lymphoma, B-Cell / Q000276:immunology*; D051379:Mice; D016328:NF-kappa B / Q000276:immunology; D012333:RNA, Messenger / Q000235:genetics; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology / Q000528:radiation effects; D015854:Up-Regulation / Q000528:radiation effects*
D000951:Antigens, Neoplasm; D018122:B7-1 Antigen; D016328:NF-kappa B; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D023201:CD40 Ligand