Construction And Characteirzation Of Adh Deletion Mutant Of Actinobacillus Pleuropneumonia

Trimeric autotransporter adhesins(TAAs) are novel virulence factor relating bacterialadhesion, belonging to the extracellular autotransporter family, which can be found in manypathogenic bacteria such as Yersinia enterocolitica, Neisseria meningitides, Moraxellacatarrhalis, Haemophilus influenzae, Bartonella henselae as well as Bartonella quintana.Actinobacillus pleuropneumoniae is the obligate causative agent of porcinepleuropneumonia, the study of its adhesion mechanism and tissue tropism is conducive toestablishing a model of interaction between respiratory pathogen and host.In earlier research, we found the complete ORF of TAAs from APP serotype5b strains L20,and speculate that the head of these TAAs with gathering a large number of YadA-like headmotifs which contains a series of sequences NSVAIG-S is the main functional domain afteranalyzing of daTAA, DNAStar and Predicting Antigenic. In this study, we constructed a mutantwith deletion of this domain using homologous recombination, named△adh, and compared theproperties of the mutant and the wild type in vitro and vivo. We found that the autoaggreation of,biofilm forming and adhesion to SJPL cell of△adh weakened obviously, while the distinction oflung injury is unconspicuous and LD50of△adh lower little than WT strain. These data provideexperimental support for learning mechanism of interaction between respiratory tract pathogensand host.