Chitosan and calcium phosphate nanoparticles (CN and CaPN) either individually or encapsulating inactivated Equine herpesvirus-1 (EHV-1) were prepared. Morphology and size of CN and CaPN before and after loading with the virus were studied. There was no cytotoxicity of CN and CaPN observed on VERO cells by two successive subcultures of inoculated cells. Infectivity test revealed that blank EHV-1and EHV-1encapsulated withCaPN(EHV-1- CaPN) titers were higher than EHV-1 encapsulated in CN (EHV-1-CN). Immune responses of (EHV-1- CN) and (EHV-1-CaPN) vaccines were evaluated by immunization of both mice and horses. In mice, (EHV-1-CN) vaccine in ratio of 1:1 induced high immune response followed
by commercial vaccine then (EHV-1-CaPN) vaccine in ratio of 1:1. By measuring the IFN-γ level in mice serum, it was found that, the highest significant level was induced in mice inoculated with EHV-1-CN at ratio of 1:1 followed by commercial EHV-1 vaccine comparing with other groups. Challenge of inoculated mice followed by virus re-isolation revealed complete viral clearance at 5th dpc in EHV-1-CN (1:1) whereas achieved at 6th, 7th, & 9th dpc in commercial vaccine, EHV-1-CN (2:1) and EHV-1-CaPN (1:1) respectively. Immunogenicity of horses vaccinated with (EHV-1-CN) vaccine (1:1) was monitored for 28
WPV. We concluded that using of chitosan nanoparticles as a novel adjuvant in preparing of EHV-1 vaccine could induce protective levels of immunity in vaccinated animals