Studies of monoclonal antibodies against human chorionic gonadotropin. II. Applications of human chorionic gonadotropin monoclonal antibodies on immunoassays.

Monoclonal antibodies generated against human chorionic gonadotropin (hCG) were utilized in radio- and enzyme-immunoassays of this reproductive hormone in biological fluids. One of the monoclonal antibodies, beta-4D6, was shown to have extremely high affinity (Ka = 8 X 10(10) M-1)) and high specificity (less than or equal to 0.6% LH cross-reactivity) to beta-subunit of hCG and whole hCG. It was used in competitive radioimmunoassays (RIA) for the determination of low levels of serum hCG. An excellent correlation was obtained concerning the assay results between the monoclonal antibody-based system and others using conventional polyclonal anti-sera. In combination with another discrete hCG monoclonal antibody, solid-phase sandwich radiometric and enzyme immunoassays were established. These immunoassays could easily be performed, and they offer sensitivity and efficacy of hCG determination comparable to those of conventional ones.