RESUMEN
Objective To clone and express alpha hemolysin ( Hla ) , one important virulence factor secreted by Staphylococcus aureus in Escherichia coli to tdetect the hemolytic activity of Hla on erythrocytes from diffrerent species ,and to prepare specific antibodies against Hla that can inhibit the hemolytic activity of Hla .Methods Hla gene was amplified by PCR using S.aureus NCTC-8325 genome DNA as a template.The expression vector pET-28a-Hla was constructed and transformed into E.coli BL21(DE3).The recombinant Hla protein was expressed by IPTG induction ,and then purified by Ni2+affinity chromatography .The hemolytic activity of Hla was measured by erythrocyte lysis assays .Results Soluble recombinant Hla protein was expressed and purified .Further investigations showed that Hla could significantly induce the lysis of rabbit erythrocytes .However , erythrocytes from humans or sheep were more resistant to the lysis mediated by Hla . The specific polyclonal antibodies against Hla ( anti-Hla) were prepared and detected by ELISA .Moreover, it was found that anti-Hla could inhibit the hemolytic activity of Hla .Conclusion We found that Hla from S.aureus has different hemolytic effects on erythrocytes from various species .The prepared Hla-antibodies can specifically block the hemolytic activity of Hla.