• Development of a subunit vaccine against bovine viral diarrhea virus (BVDV) using a truncated E2 (tE2) glycoprotein expressed in CHO-K1 cells

ANDREA PECORA; MARIA SOL PEREZ-AGUIRREBURUALDE; ZAMIT ANA; LEUNDA MR; ANSELMO ODEON; ALEJANDRA PEREZ-AGUIRREBURUALDE; DIEGO BOCHOEYER; MARCELO SPITTELER; LEVY S; DUS SANTOS MARIA JOSE; ANDRES WIGDOROVITZ

SANTIAGO

Congreso; 26th World Buiatrics Congress 2010; 2010

Bovine Viral Diarrhea Virus (BVDV), member of the Pestivirus genus, is the causal agent of a worldwide spread disease. It infects bovines of all ages, causing reproduction problems and altering biological products of high commercial value, resulting in considerable industrial losses. Disease control in Argentina is based on vaccination of the herd with inactive virus. Production of a BVDV vaccine usually presents the difficulty of obtaining enough antigen in order to induce high levels of neutralizing antibodies. An interesting alternative to inactivated vaccines are subunit vaccines, which are able to discriminate between infected from vaccinated animals. For this purpose, E2 protein is the major glycoprotein of BVDV envelope and the main target for neutralizing antibodies. Different studies on protection against BVDV infection have focused on E2, supporting its putative use in subunit vaccines. A Chinese Hamster Ovary (CHO-K1-tE2) cell line that continuously expresses a truncated version of protein E2 (tE2) was developed. Recombinant tE2 lacks the C-terminal transmembrane domain, which allows recovery of tE2 in cell culture supernatants. The concentration of recombinant E2 in CHO-K1-tE2 supernatants was 200 µg/l and its expression remained stable for at least 24 passages. Stability of tE2 in culture supernatants was evaluated after incubation at -70°C, -20°C, +4°C or +37°C for 21 days, and we obtained a satisfactory recovery of 75% under the hardest conditions assayed. Recombinant protein was recognized by an E2 specific monoclonal antibody and by bovine anti-BVDV sera. Immunogenicity of tE2 was studied through immunization of guinea pigs and cattle with different amounts of concentrated tE2 supernatants. Immunized animals showed a strong neutralizing antibody response after vaccination and protection against viral challenge.