Detection, Optimization, Characterization, and Cytotoxic Effect of Vaginolysin Extracted from Gardnerella Vaginalis Isolated from Iraqi Women Who Had Abortions

Abstract

Objective: The goal of this study is the detection of the gen that responsible for production the vaginolysin toxin, discovered the optimal condition for produce vaginolysin, purification and characterization of the toxin and show the cytotoxic effect of vaginolysin on VK2cell and HeLa cell. Methods:  Among 592 specimens isolated from pregnant women suffering from vaginal inflammation and threatened with abortion(these women is suffering from strong pain in the cervical region), only 62 of isolates identified as G vaginalis.  From Baghdad teaching hospital. detection of the gen that responsible for production the vaginolysin toxin. study of the optimal condition to produce vaginolysin. the purification of the toxin by using ammonium sulfate, ion exchange chromatography and gel filtration, toxin characterization of pH and temperature activity and stability, the study of cytotoxic effect of vaginolysin on VK2 and HeLa cells. Result: The optimal condition to produce the toxin is pH level in 4, best temperature is 37 0C, the best media is TSB broth , and the best hours is 24hr.  .  The best range for precipitation saturation ratio 50%.  ion exchanges have specific activity 4 mg.  gel filtrations show an increase in the specific activity of purified toxin (10U/mg).  the characterization done by pH and temperature,Vaginolysin  was active in 0.5 U/ mL at pH 7, and stable in pH 7 activity, the best temperature for   vaginolysin activity is 0.5 U/mL at 37°C  and maximum  stability was recorded at 37°C .   the cytotoxic effect of the toxin on VK2 cell observed the viability ratio 69.98%, at higher toxin concentration, while the result for HeLa cell viability ratio 38.77%, at higher  toxin concentration. Conclusion: vaginolysin cause lysis of vaginal cell and cervical cell may lead to abortion, the killing ratio increase by increasing the concentration of the toxin and the effect of the toxin on HeLa cell is more than on VK2 cell.