Characterization of two monoclonal antibodies against porcine VCAIM-1

Immunization of mice with TNF alpha-activated porcine endothelial cells led to the characterization of two monoclonal antibodies (MAbs), 5F3 and 8A7, specific for porcine VCAM-1, Upon flow cytometry, both antibodies increasin gly labeled endothelial cells according to their degree of activation. They bound a band of MW 80 kDa on Western blots of endothelial cells, which is the apparent molecular weight of porcine VCAM-1, It was determined by surfa ce plasmon resonance that the antibodies are directed to different antigeni c sites. It was also found that 5F3 competes for binding the antigen with a MAb previously characterized as binding domain 1 of porcine VCAM-1, Subseq uently, 5F3, but not 8A7, was found to inhibit the adhesion of human B lymp hocyte Ramos cells to porcine endothelial cells in vitro. These antibodies, which do not cross-react with human VCAM-1, might be useful for diagnostic or therapeutic purposes in xenotransplantation.