Bovine respiratory syncytial virus infection: immunopathogenic mechanisms.

Bovine respiratory syncytial virus (BRSV) causes severe respiratory disease in young cattle. Much like the human respiratory syncytial virus, BRSV induces immunomodulation in the infected host, favoring a Th2 response. Several groups have demonstrated IgE responses to BRSV proteins during infection and particularly in response to vaccination with formalin-inactivated vaccine in the field and experimentally. Newer vaccine modalities that favor a shift to Th1 cytokine production have provided promising results. Infection with BRSV is a major contributor to the multi-pathogen disease, bovine respiratory disease complex. This review stresses the unique immunomodulatory aspects of BRSV infection, vaccination and its interaction with the host's immune system.