Screening of monoclonal antibodies for hCG for affinity and specificity

Using human chorionic gonadotropin (hCG) as a model polypeptide, we have developed a strategy that allows the direct screening of supernatant fluids from hybridomas for the presence of monoclonal antibodies of high affinity and predefined specificities. The assay evaluates the competition between 125I-labeled and unlabeled homologous or heterologous antigens in a solid-phase two-site immunoradiometric assay. This assay is fast and accurate, and is of general use provided the antigen of interest can be purified in nanomolar quantities. This strategy led to the isolation of nine new monoclonal antibodies for hCG, two of which could be used for elaborating a sensitive two-site immunoradiometric assay for this hormone.