The production and characterization of a putative anti-idiotypic antibody to tumor necrosis factor-[alpha]
Bond, Arden Lenore
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Tumor necrosis factor-a (TNFa) is primarily a macrophagederived cytokine. TNFa, in vitro, kills or inhibits growth of approximately one third of surveyed transformed cell lines dincluding the L929 and WEHI 164 murine fibrosarcoma cell lines. Very little is known about the mechanisms of TNFa action. However, recently, it has been theorized that TNFa has no activity of its own and that the receptor for TNFa on the cell surface, when properly triggered, activates the cellular mechanisms which may result in the cell's death. The objective of this study was to produce an antiidiotypic antibody to TNFa to be used as a tool to study the mechanisms of TNFa action. A hybridoma that secretes an antiidiotypic antibody to TNFa (Ab2J1) has been produced and isolated following standard procedures. This antibody was found to be of isotype IgG2a as determined by an indirect ELISA test. The Ab2J1 exhibited TNFa target cell-killing capabilities in vitro. The TNFa-resistant cell lines, SP2jO and NS-1 were resistant to Ab2J1 and TNFa sensitive cells, L929 and WEHI 164, were sensitive to Ab2J1. The cell killing activity of both TNFa and Ab2f3 could be neutralized by a monoclonal anti-TNFa antibody. Both TN Fa and Ab2f3 acted in parallel having an effect on the killing of Brucella abortus strain RB51 by peritoneal macrophages, whereas neither TNFa nor Ab2f3 had an effect on the killing of strain 2308 by macrophages. These results, again indicate that TNFa and Ab2f3 have parallel dbactericidal effects and that Ab2f3 is capable of mimicking TNFa activity. The Ab2J1 was further characterized by gel electrophoresis and Western blot and was found to have two subunits of 25 and 50 kDa molecular weights similar to IgG. This anti-idiotypic antibody to TNFa may help in understanding the mechanisms of the cytotoxic activity of TNFa.
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