Purification of monoclonal antibodies from mouse ascites eliminates contaminating infectious mouse type C viruses and nucleic acids.

We examined the fate of infectious mouse type C viruses (MuLV) and nucleic acids during the purification of monoclonal antibodies (MoAbs) from mouse ascites. Hybridoma cell lines and their cell fluids can contain infectious ecotropic and xenotropic MuLV whose presence in ascitic fluid may be masked by the presence of anti-viral factors, particularly the anti-xenotropic virus neutralizing factor. They can also contain DNA and RNA. The specific techniques we used for the purification of MoAbs from the ascitic fluid completely eliminated all detectable infectious MuLV, anti-viral factors, and nucleic acids, even when these agents were added in quantities far in excess of those normally expected. Viral proteins, potentially contaminating the MoAb preparations, were also substantially reduced by our procedures. Because infectious MuLV or nucleic acids may have adverse effects on human subjects, attention should be given to each MoAb purification process to insure their effective removal.