Evaluation of a model in guinea pig (Cavia porcellus) to study the immunogenicity of inactivated commercial vaccines against bovine herpesvirus

Abstract

The objective of the present work was to evaluate the guinea pig as a model to study the immunogenicity of inactivated Bovine herpesvirus – 1 (BoHV-1) vaccines, etiological agent of Infectious Bovine Rhinotracheitis. Thirty bovines and 35 guinea pigs were used, where 10 animals per species were used as controls. Twenty bovines and 25 guinea pigs were immunized and boosted 21 days later, with a commercial vaccine containing inactivated BoHV-1 and 5, Bovine Viral Diarrhea virus type I (BVDV-I), Leptospira interrogans and Campylobacter fetus as antigens. The BoHV-1 neutralization antibody (Ab) response curve was evaluated by in vitro neutralization test up to 133 days post priming for bovines and guinea pigs. Ab titers were expressed as the reciprocal of the highest serum dilution that inhibited the citopathic effect produced by the BoHV-1 challenge virus. Maximum neutralizing Ab titers between 128 and 256 were observed at 35 days post priming in 60% of the bovines, and titers between 32 and 128 were observed at 56 days post priming in 68% of the guinea pigs. In both species, at 133 days post priming, BoHV-1 neutralizing Ab decreased below the titer of 8. The observed values are relatively similar to the ones estimated by the guinea pig model, where the abscissa of the maximum titer is at approximately 35 days post priming and the abscissa of the minimum titer of 8 is at approximately 120 days post priming. The p- value of the model was 0.0000, R2 = 84.67 %, SE = 0.2666311. These results allowed us to validate the guinea pig model to evaluate the immunogenicity of an inactivated BoHV-1 vaccine and estimate bovine BoHV-1 neutralizing titers based on the guinea pig model.