title: Development of a highly immunogenic recombinant candidate vaccine against human chorionic gonadotropin.
abstract: Human chorionic gonadotropin (hCG) is synthesized soon after fertilization and is essential for embryonic implantation. A vaccine targeting hCG would be an ideal choice for immuno-contraception; an anti-hCG vaccine developed by Talwar et al., has previously undergone Phase II efficacy trials, providing proof of principle. These trials established the threshold levels of bio-neutralizing anti-hCG antibody titers required to prevent pregnancy; however, these titers (>50 ng/ml) were achieved in only 80% of immunized women. In this communication, we report a novel recombinant anti-hCG vaccine which demonstrates improved immunogenicity. hCGβ was genetically fused at C-terminal to the B-subunit of E. coli heat-labile enterotoxin. The recombinant fusion protein (hCGβ-LTB) was expressed in Pichia pastoris and, upon adsorption on Alhydrogel along with Mycobacterium indicus pranii (MIP) as an immuno-modulator, evoked a very high anti-hCG immune response in 100% of immunized BALB/c mice. This recombinant vaccine is expected to reduce cost as well as facilitate production of a molecularly consistent conjugate on a large scale.
authors.affiliation: Talwar Research Foundation, E-8 Neb Valley, Neb Sarai, New Delhi 110068, India.
authors.forename: Shilpi
authors.initials: S
authors.lastname: Purswani
authors.forename: G P
authors.initials: GP
authors.lastname: Talwar
mesh_terms: D000818:Animals; D057134:Antibodies, Neutralizing / Q000097:blood; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D003001:Cloning, Molecular; D005260:Female; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D010843:Pichia / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology; D022642:Vaccines, Contraceptive / Q000276:immunology*; D014614:Vaccines, Synthetic / Q000276:immunology
chemical_list: D057134:Antibodies, Neutralizing; D018997:Chorionic Gonadotropin, beta Subunit, Human; D011993:Recombinant Fusion Proteins; D022642:Vaccines, Contraceptive; D014614:Vaccines, Synthetic