Immunochemical and biological properties of monoclonal antibodies (MCAs) against human chorionic gonadotrophin (hCG).

The paper reviews properties and applications of MCAs against hCG in comparison with classical antisera against this hormone. The first part begins with a brief survey of immunochemical tests and assays based on classical antisera to set the stage for the use of MCAs in various test systems. Monoclonal antibodies (MCAs) against hCG are often subdivided in three groups depending on where the epitope on the antigen is situated: on the alpha or beta-subunit, or solely on the complete hCG molecule. MCAs belonging to these three groups were investigated both immunochemically and biologically. Competitive immunoassays using anti-alpha MCAs do not discriminate against the other glycoprotein hormones (LH, FSH, TSH). Application of anti-beta MCAs can but need not lead to assays specific for hCG. The same was found for those MCAs which react with the complete hCG but not with its subunits (anti-alpha beta). These competitive assay systems are usually of mode-rate sensitivity since MCAs with high affinities (K greater than 10(10)) are quite rare. In contrast, application of selected combinations of two MCAs in sandwich assays (with either an enzyme or a radioactive isotope as label) or in agglutination tests (using erythrocytes, latex or gold sol particles) lead to much more specific and sensitive assay systems. In the second part, biological biological activities of classical antibodies but particularly of MCAs are discussed. Most MCAs against hCG studied by us were unable to affect the biological activity of the hormone. The few which did, either potentiated or inhibited the biological activity.(ABSTRACT TRUNCATED AT 250 WORDS)