Different cross protection scopes of two avian influenza H5N1 vaccines against infection of layer chickens with a heterologous highly pathogenic virus

摘要: Avian influenza (AI) virus strains vary in antigenicity, and antigenic differences between circulating field vaccine will affect the effectiveness of vaccination poultry. Antigenic relatedness can be assessed by measuring serological cross-reactivity using haemagglutination inhibition (HI) tests. Our study aims to determine relation expressed Archetti-Horsfall ratio, reduction transmission highly pathogenic H5N1 AI among vaccinated layers. Two vaccines were examined, derived from A/Ck/WJava/Sukabumi/006/2008 A/Ck/CJava/Karanganyar/051/2009. Transmission experiments carried out four two control groups, with six sets 16 specified pathogen free (SPF) layer chickens. Birds at 4weeks age one strain challenge-infected homologous or heterologous 8weeks age. No shedding occurred groups challenged strain. In group Karanganyar strain, high cross-HI responses observed, no Sukabumi occurred. However, titres low, was not reduced, multiple transmissions contact birds observed. This showed large cross-protection based on different strains. implies that extrapolation vitro data clinical protection might straightforward.