An anti-human recombinant tumor necrosis factor alpha (TNF ) monoclonal antibody recognizes an epitope in feline TNFAdam Aguirre, Alejandro Escobar, Viviana Ferreira, María C. Molina, Arturo Ferreira and Juan C. Aguillón
Disciplinary Program of Immunology, Institute of Biomedical Sciences (ICBM), Faculty of Medicine, University of Chile, Independencia 1027, Casilla 13898, Correo 21, Santiago, CHILE
(Received 11 February 2002; accepted 10 October 2002)
It is likely that the murine response to human recombinant TNF (hrTNF ) may generate antibodies (Ab) to epitopes present in TNF from other species. Here, we demonstrate that F5 anti-hrTNF monoclonal antibody (mAb) recognizes feline TNFa while E8 anti-hrTNF mAb failed to do so. In order to demonstrate that E8 and F5 mAb recognize different epitopes in the hrTNF molecule, a constant concentration of E8 and variable concentrations of F5 were incubated with solid phase bound hrTNF . Binding of E8 and F5 to hrTNF was determined with anti- and chain specific Ab. F5 bound equally to hrTNF in the presence or absence of E8 and the same amount of E8 bound to hrTNF , in spite of the presence of F5. When using the E8 and F5 mAb for capturing the TNF from the equine, canine, feline and bovine species, in supernatants of an ex vivo lipopolysaccharide (LPS)-stimulated whole blood cell culture, we only detected the feline TNF by F5 mAb ( p = 0.001). By a cytotoxic assay on L929 fibroblasts, we indeed demonstrated the feline TNF production after the LPS stimulus. In an inhibition assay, the human and feline cytokines competed for F5, although the inhibition of native human TNF binding to F5 was significant but only about 20% ( p = 0.001). In conclusion, most likely the F5 anti-hrTNF mAb recognizes an epitope in feline TNF . Its immunomodulatory potential in the feline model remains to be studied.
Key words: Monoclonal antibodies / Tumor necrosis factor alpha / Cross-reactivity
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