Immunogenicity of equine herpesvirus type 1 (EHV1) and equine rhinovirus type 1 (ERhV1) following inactivation by betapropiolactone (BPL) and ultraviolet (UV) light

Abstract

Some kinetic data on the inactivation of equine herpesvirus type 1 (EHV1) and equine rhinovirus type 1 (ERhV1) by betapropiolactone (BPL) and ultraviolet (UV) irradiation are reported. 0.25% BPL at 37°C for 1 h reduced the titre of EHV1 by > 10 3.4 and of ERhV1 by > 10 4.1 TCID 50/ml. UV irradiation (334 μW/cm 2) produced similar reductions in titre after 2 min. These data were used as a basis for inactivating EHV1 and ERhV1 by the combined action of BPL and UV irradiation. Viruses were exposed to 0.1% BPL for 1 h at 4°C with constant stirring, followed by UV irradiation for 2 min, followed by incubation for 3 h at 37°C. Inactivated EHV1 elicited secondary immune responses only in horses whereas ERhV1 produced primary immune responses in mice (including athymic nu/nu mice), rabbits and probably in horses.