Two-site assay of human alpha 1-fetoprotein using 125I-labelled monoclonal antibodies

Monoclonal antibodies to human alpha 1-fetoprotein (AFP) have been compared with a conventionally produced antiserum using radioimmunoassay and two-site immunoradiometric techniques. A low-affinity antibody, which proved inadequate for use in a radioimmunoassay, gave a satisfactory dose-response curve in a rapid two-site assay. A higher-affinity antibody yielded a simple, rapid, and sensitive two-site assay suitable for routine measurement of serum AFP.