Effects of DL-Penicillamine on Cytotoxic Reaction between Baboon Performed Xenoantibodies and Pig Endothelial Cells

The purpose of this study was to evaluate effects of DL-Penicillamine (DLP), a compound interrupting S-S bonds (IgM pentamers) on binding and cytotoxicity of adult baboon performed xenoantibodies to pig endothelial cells. Pooled baboon serum was treated with different concentrations of DLP during various periods of time. Complement-mediated cytotoxicity assay was used to determine the reactivity of baboon xenoantibodies to pig aortic endothelial cells (PAEC). To assess IgM and IgG binding to PAEC, ELISA method was applied. Serum treated with DLP revealed significant reduction of cytotoxicity in a dose dependent manner. Cytotoxicity was also reduced during time prolongation of DLP exposure to PAEC. Results indicate that baboon performed IgM and IgG xenoantibodies bind to pig endothelial cells, but only IgM is able to cause degradation of the complement. DLP significantly reduces cytotoxicity and eliminates binding of IgMs to PAEC in spite of continued binding of IgG xenoantibodies to the surface of endothelium.