EPITOPE MAPPING AND FUNCTIONAL-ANALYSIS OF 3 MURINE IGG1 MONOCLONAL-ANTIBODIES TO HUMAN TUMOR-NECROSIS-FACTOR-ALPHA

Immunologic and enzyme digest epitope mapping techniques were used to compare and contrast the interactions of three mouse mAb, designated A 10G10, A6, and B6, with human TNF-alpha. These antibodies have previou sly been shown to protect mouse and human cells from TNF toxicity. ELI SA showed that the antibodies recognize predominantly conformational e pitopes, and that native TNF binds at least two molecules of the same mAb. Enzyme digestion of native TNF bound to each of the mAb in turn s howed that each of the antibodies binds to or sterically masks a large fraction of the exposed surface of TNF. These epitope mapping data we re compared with four putative TNF cell receptor binding sites present ed in the literature. The results are consistent with the hypothesis t hat these antibodies prevent TNF-induced cell death by binding to or s terically masking the TNF receptor binding site.