〔Abstract〕 Objective To investigate the toxicity and mechanism of a novel Staphylococcus aureus with incomplete hemolytic phenotype(SIHP) filtrate on non-small cell lung cancer(NSCLC) HCC827 cell line.Methods The filtrates and diluents of novel SHHP and Staphylococcus aureus with complete hemolytic phenotype(SCHP) were coincubated with 1% human red blood cells and HCC827 cells.Hemoglobin release method was used to detect red blood cell toxicity,CCK-8 method was used to detect HCC827 cell activity.Ion selective electrode method,colorimetric method and immunofluorescence method were used to detect potassium(K+),lactate dehydrogenase(LDH) and interleukin-6(IL-6) concentrations in the incubation supernatants.Results The filtrate and diluent of novel SIHP could significantly damage the activity of HCC827 cells,causing K+and LDH leakage.The filtrate and 1:3 diluent of novel SIHP resulted in a decrease and an increase in IL-6 secretion in HCC827 cells,respectively.Compared with SCHP,the filtrate and diluent of novel SIHP had stronger red blood cell toxicity and more severe K+leakage in HCC827 cells.Conclusion The filtrate of novel SIHP can damage the cell membrane,lead to content release and kill NSCLC cells,with a stronger toxicity than SCHP.