Human and primate monoclonal antibodies for in vivo therapy

Human monoclonal antibodies, owing to their decreased immunogenicity, are expected to be an improvement over mouse monoclonal antibodies for in vivo therapy. Human and primate monoclonal antibodies are best produced with a human x mouse heteromyeloma. Several human chromosomes are stable in the human x (human x mouse) hybrids. Chimpanzee anti-digoxin monoclonal antibodies were prepared and characterized. Because they are structurally very similar to human antibodies, they should be well tolerated in humans. The anti-digoxin antibodies can be used for therapy of extreme overdoses or as an in vivo diagnostic tool for slight overdoses. Because the advantage of using human monoclonal antibodies is their lack of immunogenicity, preparation of the antibody must be scrupulous so as not to introduce extraneous immunogens. Analysis to ensure the purity of the preparation can be complicated by the presence of high concentrations of the antibody and the low levels of contamination that must be detected. We describe a Western blot assay for Protein A that is sensitive even in the presence of human IgG.