The Recombinant Vaccine against Human Chorionic Gonadotropin goes on Combined Immunogenicity, Safety and Efficacy Clinical Trials

Abstract

The above mentioned vaccine in the form made in the laboratory was expensive and time consuming. In order to render it amenable to industrial production, we made a genetically engineered version of the vaccine, in which beta subunit of hCG was linked to B subunit of heat labile enterotoxin of E. coli as carrier [4]. Figure 1 shows the sequence of nucleotides of this recombinant vaccine.The recombinant vaccine adsorbed on alhydrogel with adjuvant autoclaved Mycobacterium indicus pranii (MIP), induced fairly high anti-hCG antibodies in not only BalbC, but also in other genetic strains of mice [5,6]. MIP is a potent invigorator of immune response [7]. Figure 2 shows the antibody titersand their duration in BalbC mice. It may be recalled that at 50 ng/ml antibody titers and above, women are protected to become pregnant. This recombinant vaccine was therefore highly immunogenic at least in mice. Priming with DNA vaccineGenetically engineered vaccines are made as both DNA and protein. What was amazing was the observation that if primary immunization is done with the DNA form of the vaccine, followed by injections of the Protein form of the vaccine, the antibody response is substantially higher (Figure 3). Thus to obtain optimal antibody response, the schedule of immunization will be to immunize with 2 primary injections of DNA form of the recombinant vaccine to begin with, followed by third and subsequent injections with the protein form of the recombinant vaccine.