Induction of acute phase protein by recombinant human interleukin-6 (IL-6) in calves.

Interleukin-6 (IL-6) is a major inducer of acute phase proteins in human and murine species. However, the effects of IL-6 have not yet been investigated in cattle. Following continuous infusion of recombinant human IL-6, serum concentrations of bovine haptoglobin and fibrinogen increased in a manner similar to those in cattle with acute phase reaction. In contrast, C-reactive protein and alpha 1-acid glycoprotein, as well as the other hematologic parameters, did not change significantly. Intravenous administration of recombinant human IL-6 resulted in only a mild and transient increase of bovine haptoglobin. These results suggest that the regulation of acute phase protein production in cattle is similar, but not identical, to that observed in human and murine species.