Evaluation of viral shedding and immune response following vaccination with a modified live BHV1 vaccine

Abstract

The purpose of the study was to monitor Bovine Herpesvirus-1 (BHV1) shedding to susceptible herdmates after vaccination with a modified live BHV1 vaccine and to monitor the development of the cell-mediated immune response to BHV1 (as measured by antigen specific lymphocyte blastogenesis). Ten calves received a modified live virus (MLV) vaccine containing BHV1, bovine viral diarrhea virus, parainfluenza 3 virus and bovine respiratory syncytial virus. Five calves that were seronegative for BHV1 served as contact controls. Multiple attempts to isolate BHV1 from nasal swabs and buffy coat cells from vaccinates and control animals between days 0 and 21 were all negative. By six days post-vaccination five out of ten vaccinated calves had a detectable post-vaccination lymphocyte blastogenic response to BHV1 antigen. The response continued to increase until at least 28 days after vaccination, at which time all ten calves exhibited a detectable response. None of the contact control animals developed an antibody or lymphocyte blastogenic response to BHV1 antigens. These results indicate that the MLV-BHV1vaccine used in this study induced an early and strong cell-mediated immune response as measured by lymphocyte blastogenic responsiveness to BHV1 antigens and the vaccine virus was not shed to susceptible herdmates.