Therapeutic effect of anti-feline TNF-alpha monoclonal antibody for feline infectious peritonitis.

Feline infectious peritonitis virus (FIPV) replication in macrophages/monocytes induced tumor necrosis factor (TNF)-alpha production, and that the TNF-alpha produced was involved in aggravating the pathology of FIP. We previously reported the preparation of a feline TNF-alpha (fTNF-alpha)-neutralizing mouse monoclonal antibody (anti-fTNF-alpha mAb). This anti-fTNF-alpha mAb 2-4 was confirmed to inhibit the following fTNF-alpha-induced conditions in vitro. In the present study, we investigated whether mAb 2-4 improved the FIP symptoms and survival rate of experimentally FIPV-inoculated SPF cats. Progression to FIP was prevented in 2 out of 3 cats treated with mAb 2-4, whereas all 3 cats developed FIP in the placebo control group. Plasma alpha1-glycoprotein and vascular endothelial growth factor levels were improved by the administration of mAb 2-4, and the peripheral lymphocyte count also recovered. These results strongly suggested that the anti-fTNF-alpha antibody is effective for the treatment of FIP.