Canine zona pellucida glycoprotein-3: Up-scaled production, immunization strategy and its outcome on fertility

Abstract Zona pellucida (ZP) glycoproteins based contraceptive vaccines have been proposed for the management of wildlife population. In the present study, a fusion protein encompassing promiscuous T cell epitope of tetanus toxoid [TT; amino acid (aa) residues 830–844] followed by a dilysine linker and an ectodomain of dog ZP3 (ZP3; aa residues 23–348) without any affinity tag (TT-KK-ZP3) has been expressed in Escherichia coli . The recombinant protein was successfully produced in fed-batch fermentor and purified. The average yield of purified refolded protein was 12.20 ± 0.61 mg/2 g wet cell pellet. Female FvB/J mice immunized with the varying doses of recombinant TT-KK-ZP3 supplemented with alum/PetGel A as adjuvants following a three injection schedule, showed dose dependent increase in serum IgG titer. Antibodies against TT-KK-ZP3 recognized native mouse/dog ZP and significantly inhibited mouse in-vitro fertilization ( p  = 0.012). Immunized mice showed significant reduction in fertility ( p