Abstract: It was found that trimeric autotransporter adhesin (TAA) was the important virulence factor for Actinobacillus pleuropneumoniae(APP) adhere to host in the recent years. In this research, we compared the culture characteristic and the pathogenicity to piglet of △adh and 5b wild strain. The results showed, the growth rate of △adh was higher than 5b obviously; the △adh showed weaker aggregation compared with 5b in liquid culture condition; the piglet showed typical symptoms after the infection, the observation of HE showed pathogenicity of the △adh was weaker than 5b wild strain. The result of the comparisons conformed the importance of adh in the progress of APP attacking to host and set basics in the pathogenic research of APP for the next step.

Key words: Actinobacillus pleuropneumoniae; △adh; culture characteristic; pathogenicity