title: Irradiation up-regulates CD80 expression through two different mechanisms in spleen B cells, B lymphoma cells, and dendritic cells.
abstract: We have previously demonstrated irradiation-induced up-regulation of CD80 expression in A20-HL B lymphoma cells by inducing expression of tumour necrosis factor-alpha (TNF-alpha) and CD154. In the present study, we investigated whether irradiation also up-regulates CD80 expression in mouse spleen B cells. Because freshly prepared spleen B cells are highly sensitive to irradiation, we employed spleen B cells stimulated with lipopolysaccharide (LPS-B cells). X-irradiation (8 Gy) followed by incubation (9-12 hr) highly and selectively up-regulated CD80 expression in LPS-B cells, whereas the same treatment slightly increased expression of CD54 and did not affect expression of CD86, major histocompatibility complex class II, CD11a or surface immunoglobulin M. The irradiation-induced up-regulation of CD80 expression resulted in enhanced APC function of LPS-B cells. Up-regulation of CD80 expression on LPS-B cells was accompanied by an increase in CD80 mRNA accumulation and nuclear factor (NF)-kappaB activation. Activation of NF-kappaB was shown to be critical for up-regulation of CD80 expression as pyrrolidine dithiocarbamate (PDTC), an inhibitor of NF-kappaB, severely decreased the observed up-regulation. X-irradiation of LPS-B cells induced expression of TNF-alpha but not CD154. However, anti-TNF-alpha monoclonal antibody (mAb) with anti-CD154 mAb did not inhibit X-irradiation-induced up-regulation of CD80 expression in LPS-B cells, whereas these mAbs almost completely inhibited this up-regulation in A20-HL cells and bone marrow-derived dendritic cells (DCs). In contrast, a thiol antioxidant, N-acetyl-l-cysteine, completely blocked X-irradiation-induced up-regulation of CD80 expression in LPS-B cells, but not in A20-HL cells or in DCs. Based on these findings, we concluded that X-irradiation up-regulates CD80 expression not only in A20-HL cells and DCs but also in LPS-B cells, and that this up-regulation in LPS-B cells via NF-kappaB activation is dependent on the generation of reactive oxygen species, while that in A20-HL cells and DCs is not.
authors.affiliation: Department of Immunology, Toho University School of Medicine, Tokyo, Japan.
authors.forename: Hideko
authors.initials: H
authors.lastname: Torihata
authors.forename: Fumio
authors.initials: F
authors.lastname: Ishikawa
authors.forename: Yayoi
authors.initials: Y
authors.lastname: Okada
authors.forename: Yuriko
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Uchida
authors.forename: Toru
authors.initials: T
authors.lastname: Suguro
authors.forename: Terutaka
authors.initials: T
authors.lastname: Kakiuchi
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology; D000818:Animals; D017951:Antigen Presentation / Q000528:radiation effects; D001402:B-Lymphocytes / Q000276:immunology / Q000528:radiation effects*; D018122:B7-1 Antigen / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000276:immunology / Q000528:radiation effects*; D016166:Free Radical Scavengers / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000276:immunology; D008213:Lymphocyte Activation / Q000528:radiation effects; D016393:Lymphoma, B-Cell / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D016328:NF-kappa B / Q000276:immunology; D018384:Oxidative Stress / Q000276:immunology; D012333:RNA, Messenger / Q000235:genetics; D013154:Spleen / Q000276:immunology; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects / Q000528:radiation effects*
chemical_list: D018122:B7-1 Antigen; D016166:Free Radical Scavengers; D008070:Lipopolysaccharides; D016328:NF-kappa B; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D000111:Acetylcysteine