The present study reports the use of guinea pigs as a model to study the immunogenicity of bovine herpesvirus type 1 (BoHV-1) and bovine viral diarrhea virus (BVDV) inactivated vaccines. To this purpose, guinea pigs (60) and calves (10) were immunized twice with a 28 day interval with an experimental vaccine containing antigens of both viruses and tested for virus neutralizing (VN) antibodies 28 days after the second dose. Calves were immunized with the recommended dose (5mL), while the guinea pigs were distributed in six groups and immunized with fractionated doses (0.005 to 1.6mL). Guinea pigs immunized with 1/16 (0.320mL) and 1/8 (0.640mL) of the bovine dose developed VN titers (GMTs) of 6.46 and 7.56, respectively, which were equivalent to the titers developed by calves (GMT=8) (P>0.05). A high correlation (R²=0.95) was observed between the antigen dose and the VN titer developed by all guinea pig groups. On the other hand, it was not possible to establish an antigen dose that induces in guinea pigs a serological response to BVDV equivalent to that induced in calves. Only the two groups given the highest antigen doses developed a consistent anti - BVDV neutralizing response, yet with VN titers (GMT= 8 and 9, respectively) significantly lower (P<0.05) than that induced in calves (GMT=34.9). These results demonstrate that guinea pigs may be used as a model to test the immunogenicity of BoHV-1 inactivated vaccines. Volumes between 1/8 and 1/16 of the bovine dose induce in these animals a VN antibody response of equivalent magnitude to that induced in calves.
BoHV-1; BVDV; experimental model; guinea pigs; vaccine test
