PRELIMINARY STUDIES WITH RECOMBINANT CHORIONIC-GONADOTROPIN BETA-SUBUNIT PRODUCED IN ESCHERICHIA-COLI FOR USE AS AN ANTIGEN IN A BIRTH-CONTROL VACCINE

PROBLEM: Prototype human chorionic gonadotropin (hCG) vaccines based a n natural sources are unsuitable for widespread applications due to th eir complex manufacturing procedures, cost, and carrier-mediated immun e suppression. METHOD OF STUDY: Wistar rats were immunized with alum-a dsorbed CGP (recombinant), CG beta-TT, and nCG beta (native CG beta)-T T, whereas Bonnet monkeys were immunized with only CG beta. The anti-h CG antibody titre in the sera obtained at different time points were q uantified by radioimmunoassay, The sera of Wistar rats were characteri zed in terms of their affinity to hCG, bioneutralization capacity (by inhibition of hCG-induced testosterone production in Leydig cells), an d cross-reactivity with human luteinizing hormone, human follicle-stim ulating hormone, and human thyroid-stimulating hormone (by direct bind ing assays). RESULTS: Antigen-binding capacities of sera obtained upon immunization with CGP were 3.080 +/- 943 ng/ml (n = 6) and 3,993 +/- 1292 ng/ml (n = 4), respectively, in rats and mon keys. The analysis o f data revealed that immunization of rats with CGP produced antibodies comparable to that of CG beta-TT and nCG beta-TT. CONCLUSION: The stu dy opens up the possibility of producing pure and highly immunogenic C G beta by a recombinant DNA route, as a consistent source of antigen f or birth control vaccine.