分泌型核酸酶SsnA介导猪链球菌2型逃避中性粒细胞胞外陷阱捕杀的研究

The study on DNase SsnA mediated Streptococcus suis serotype 2 escaping neutrophil extracellular traps killing

为了研究猪链球菌分泌型核酸酶SsnA能否介导猪链球菌2型逃避中性粒细胞胞外陷阱(NETs)的捕杀,试验通过构建猪链球菌2型(SS2)菌株的ssn A基因缺失突变株和回复株,比较三者在体外降解DNA的效率、降解NETs的能力及对NETs杀菌效率的影响。结果表明:ssn A基因缺失后的SS2不能在体外降解DNA及经PMA刺激诱导形成的NETs,同时降低了NETs对于SS2的捕杀作用。说明SS2能够通过胞外核酸酶SsnA来降解NETs的DNA骨架,从而逃避NETs的捕获作用而存活。

The aim of the present study was to identify whether DNase SsnA could mediate Streptococcus suis serotype 2 （SS2） escaping neutro phil extracellular traps killing. The SsnA deletion mutant strain and the complement strain of the mutant were constructed. Then the efficiency of degradation of DNA in vitro, the ability of degradation of NETs and effect on efficiency bactericidal of the NETs were identified between the wild type, mutant and complement strains. The results showed that the DNA and NETs induced by PMA stimulation could not be degraded by the SsnA deletion mutant. The bactericidal effect of NETs on SS2 was also significantly attenuated by the deletion of the SsnA gene. The results indicated that SsnA was a specific NETs evasion factor.