Infectious laryngotracheitis (ILT) is a poultry respiratory disease associated with considerable mortality in chicken and lowering egg production. Vaccination along with biosecurity measures are considered the main strategy for ILT control. This study was aimed to evaluate the potency of an inactived ILT vaccine candidate provided from a local ILTV isolate. The isolated virus was characterized and treated with various chemicals concentrations. The virus infectivity was entirely abolished by treatment of 3mM binary ethylene imine following 16 hours incubation. The inactivated ILTV suspension was adjuvanted and its immune response was evaluated in both SPF chickens (experiment-I) and Hyline pullets (experiment-II). Efficacy of the combination of the inactivated and live ILT vaccines was compared. The results of experimrnt-I showed that the inactivated antigen raised specific antibody titers against ILTV. In experiment-II, despite the increase in serum antibody level administration of the inactivated antigen alone did not offer sufficient protection. The full protection was found in chickens that received the combination regimen. It was concluded that simultaneously administration of the inactivated and live ILT vaccines was efficient for induction of immunity against ILTV. Keywords: infectious laryngotracheitis virus; vaccine; inactivation; immune response.

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