Immunochemical Characterisation of a Murine Monoclonal Anti-Idiotypic Antibody

Abstract Y7, a murine monoclonal IgGl k antibody against a human monoclonal IgM λ DJ molecule, was affinity purified on an IgM λ immunoaffinity column. As detected by enzyme-linked immunosorbent assay (ELISA) the isolated Y7 monoclonal antibody was shown to be not cross-reactive with human IgG, human secretory IgA, μ chain, λ+k chains and another human monoclonal IgM λ BR. Binding to the polyclonal human IgM standard in the same assay was about 30 percent. The epitope specificity of affinity purified and biotinylated Y7 MoAb was localized only in the nonreduced pepsin Fab fragments of IgM λ DJ immunogen. As the immunogen was determined to be a specific antibody to phosphorylcholine, the specificity of Y7 MoAb was further ascertained in its capacity to induce 95% inhibition of immunogen binding for phosphorylcholine.