A vectored equine herpesvirus type 1 (EHV-1) vaccine elicits protective immune responses against EHV-1 and H3N8 equine influenza virus

Vaccination is commonly used to control equine respiratory pathogens such as equine herpesvirus type 1 (EHV-1) and equine influenza virus (EIV). Here, we describe the generation and characterization of a recombinant EHV-1 modified live virus vaccine (MLV) based on a recent abortogenic EHV-1 strain, NY03 The immunogenicity and efficacy of the MLV was tested in horses in an EHV-1 vaccination/challenge experiment using the highly virulent neurovirulent EHV-1 strain OH03 Induction of a robust EHV-1-specific immune response was observed Upon challenge infection, vaccinated horses were partially protected against disease as demonstrated by a significant reduction in clinical signs, nasal shedding and viremia levels In addition, the NY03-based MLV was used to express the EIV H3 protein and immunogenicity was tested in horses. Expression of H3 was readily detected in NY03-H3-infected cells in vitro Vaccination of horses resulted in the induction of a robust serological Immune responses against two recent but genetically distinct EIV representatives. VA05 and NY-99, which were above the threshold predicted to be protective against development of clinical disease (C) 2009 Elsevier Ltd All rights reserved