Tumor necrosis factor augments the immunogenicity and the production of L-ornithine by peritoneal macrophages.

The release of ornithine by macrophages and its correlation with their immunogenicity after treatment with recombinant human tumor necrosis factor-alpha (TNF) were analyzed. TNF was found to augment the capacity of peritoneal macrophages to convert 14C-labeled arginine into L-ornithine and to release L-ornithine into the culture medium. In agreement with the previous observation that L-ornithine potentiates immune responses in vivo, it was also found that treatment of peritoneal exudate cells with TNF augments the capacity of these cells to immunize mice in vivo for a subsequent secondary in vitro cytotoxic response against non-major-histocompatibility antigens.