Successful cross-protective efficacy induced by heat-adapted live attenuated nephropathogenic infectious bronchitis virus derived from a natural recombinant strain.

摘要: A natural recombinant nephropathogenic K40/09 strain of infectious bronchitis virus (IBV) was heat-adapted for possible future use as live attenuated vaccine. The selected during successive serial passages in specific-pathogen free (SPF) embryonated eggs at sub-optimal higher temperature (56°C). Unlike the parental strain, designated HP50, found to be safe 1-day-old SPF chicks, which showed neither mortality nor signs morbidity, and rarely induced ciliostasis or histological changes trachea kidney after intraocular fine-spray administration. HP50 provided almost complete protection against two distinct subgroups a (KM91-like QX-like subgroup) elicited production high titers neutralizing antibody (neutralization index 3.6). We conclude that vaccine is rapidly by heat adaptation exhibits desired level attenuation, immunogenicity, protective efficacy required These results indicate could helpful reduction economic losses caused recently emergent IBV infection many countries.