Development and statistical validation of a guinea pig model as an alternative method for bovine viral vaccine potency testing

PARREÑO, VIVIANA; Y COL.

Buenos Aires

Simposio; Symposium: Practical Alternatives to reduce animal testing in quality control of veterinary biologicals in the Americas.; 2010

IABS-OIE

Development and Statistical Validation of a Guinea Pig model for Vaccine Potency testing against Infectious Bovine Rhinothracheitis Virus (IBR). Parreño, Viviana1; López; María Virginia2; Rodriguez, Daniela1; Vena, María Marta3. Izuel, Mercedes3; Filippi, Jorge 3; Romera, Alejandra1; Faverin, Claudia4; Susana Levy3, Bellinzoni, Rodolfo3, Fernandez, Fernando1 and Marangunich, Laura5  vparreno@cnia.inta.gov.ar 1Instituto de Virología, CICV y A – INTA. 2Universidad de Buenos Aires, Facultad de Agronomía. 3Biogénesis Bagó S.A. 4Universidad Nacional de Mar del Plata. 5Universidad Nacional de Tres de Febrero, UNTREF, Buenos Aires, Argentina Infectious Bovine Rhinothracheitis (IBR) caused by bovine herpesvirus 1 (BoHV-1) infection is distributed worldwide. The aim of this work was to validate a guinea pig model as an alternative method for BoHV-1 vaccine potency testing. BoHV-1 antibody (Ab) response to vaccination in guinea pigs, measured by ELISA and virus neutralization (VN), was statistically compared to the Ab response in cattle. The guinea pig model showed a dose response relationship to antigen concentration in the vaccine and it was able to discriminate among vaccines containing 1 log10 difference in its BoHV-1 concentration with very good repeatability and reproducibility (CV≤20%). A regression analysis of the Ab titers obtained in guinea pigs and bovines at 30 and 60 dpv, respectively, allowed us to classify vaccines in three potency categories: “very satisfactory”, “satisfactory” and “unsatisfactory”. Bovines immunized with vaccines corresponding to each of these three categories were experimentally challenged with BoVH-1 virus and protection rates correlated well with the assigned category.  Concordance analysis of data generated by 85 experiments, which included vaccination of calves and guinea pigs with 18 vaccines of known potency, 8 placebos and 18 commercial vaccines, indicated almost perfect agreement between the model and the target species for Ab titers measured by ELISA and VN. The developed guinea pig model is ethically aligned with the 3R principle of animal welfare and represents a reliable tool to estimate batch-to-batch vaccine potency and to predict efficacy of killed BoHV-1 veterinary vaccines in cattle.