Enhancement of antigen-presenting ability of B lymphoma cells by partial inhibition of protein synthesis through inducing B7-1 expression.
During the investigation of the role of protein synthesis in antigen-presenting cell (APC) function of A20-HL B lymphoma cells, we found that partial inhibition of protein synthesis enhanced their APC function. The treatment of A20-HL cells with 0.313-2.5 microM emetine, an irreversible inhibitor of protein synthesis, decreased protein synthesis by 60-70%, and enhanced their APC function to stimulate I-Ad/OVA323-339-specific T cells to produce interleukin-2 in response to ovalbumin (OVA). The emetine-treated and paraformaldehyde-fixed A20-HL cells required only 20 nM OVA323-339 peptide to stimulate the T cells, whereas those untreated and fixed required 200 nM peptide. This enhancement of APC function was mostly because of the induction of B7-1 expression on A20-HL cells by the emetine treatment, since B7-1 molecules were detected on the emetine-treated A20-HL cells, but only negligibly, if at all, on the untreated cells, and an anti-B7-1 monoclonal antibody, 1G10, inhibited the enhanced APC function of the emetine-treated A20-HL cells. The emetine-treatment also increased B7-1 mRNA expression in A20-HL cells, suggesting that the induction of B7-1 expression was due to the increase in the accumulation of mRNA and the translation with residual ability to synthesize protein. Thus, partial inhibition of protein synthesis in A20-HL cells increases B7-1 mRNA accumulation and its expression on the cell surface, which results in the enhancement of their APC function.
Aoi
T
T
Department of Immunology, Toho University School of Medicine, Tokyo, Japan.
Nakano
H
H
Tanaka
Y
Y
Kakiuchi
T
T
D017951:Antigen Presentation / Q000187:drug effects / Q000276:immunology*; D000938:Antigen-Presenting Cells / Q000187:drug effects; D018122:B7-1 Antigen / Q000235:genetics / Q000276:immunology*; D004640:Emetine / Q000494:pharmacology; D006801:Humans; D016393:Lymphoma, B-Cell / Q000276:immunology* / Q000378:metabolism; D009363:Neoplasm Proteins / Q000096:biosynthesis*; D010047:Ovalbumin / Q000276:immunology; D012333:RNA, Messenger / Q000235:genetics; D016707:Tissue Fixation; D014407:Tumor Cells, Cultured
D018122:B7-1 Antigen; D009363:Neoplasm Proteins; D012333:RNA, Messenger; D010047:Ovalbumin; D004640:Emetine