• Development of a BRV VP6 subunit vaccine and its evaluation in the calf colostrum-deprived model

GONZALEZ D; MOZGOVOJ M; BELLIDO D; RODRIGUEZ D; WIGDOROVITZ A; PARREÑO V; DUS SANTOS MARIA JOSE

Ouro Preto, Brasil

Congreso; 8th International Veterinary Immunology Symposium; 2007

Development of a BRV VP6 subunit vaccine and its evaluation in the calf colostrum-deprived model. Diego D Gonzalez, Marina V Mozgovoj, Demian Bellido, Andrés Wigdorovitz, Viviana Parreño, María J Dus Santos Instituto de Virología, CICVyA, INTA, Castelar, Buenos Aires, Argentina Group A rotaviruses are the main cause of acute viral gastroenteritis in humans and animals throughout the world. In our country bovine rotavirus is one of the main causes of neonatal (<3 weeks) calf diarrhea and significant economic losses. Due to the early susceptibility to the infection prevention strategies are based on the improvement of passive immunity levels through the vaccination of pregnant cows in the last third part of gestation. The major capsid antigen (VP6) of bovine rotavirus is the most immunogenic viral protein. We have previously reported that VP6 {group A P[1]G6} BRV C-486 strain expressed in the baculovirus system was able to induce high levels of passive protection in a suckling mice model. The objective of this work was to evaluate the VP6 immunogenic properties in calves, by using  a calf model of passive protection. Recombinant VP6 using the baculovirus system was used to immunize cows in the last third of pregnancy. First and second colostrum of these animals were collected, pooled, and the antibody titers were determined in order  to generate an hyperimmune colostrum that was used to feed colostrum-deprived calves within the first 6 h of life. Colostrum-deprived calves receiving one dose of pooled immune colostrum, or calves receiving control colostrum, were orally inoculated with 2*106 FFU of IND (P[5]G6) BRV at 2 days of age. Both groups were monitored for diarrhea, virus shedding and anti-BRV antibodies titers both in feces and serum. The results demonstrated that it was possible to reduce both diarrhea and virus shedding (in terms of viral titer and excretion period) in the group receiving immune colostrum against VP6 in comparison with the group fed with control colostrums. Corresponding author: dgonzalez@cnia.inta.gov.ar