Preparation And Immunoprotective Effects Of A Liposomal Lipopolysaccharide From Multi-drug Resistant Escherichia Coli

ObjectiveWhereas the small dose of LPS in the research can strengthen immunity and include LPS tolerance and anti-tumor effects. Our research is to prepare a liposomal lipopolysaccharide(LPS) of Escherichia coli separated from clinic,and to observe the immunoprotective effects so as to seek after the newly method that availablilty prevent the multi-drug resistant hospital infection bacteria as well as the newly approach that prevent tumour disease.MethodLPS were isolated from multi-drug resistant bacteria strains which were separated from clinic by enzyme extraction, using the Limulus amoebocyte lysate(LAL) assay to measured the endotoxic activities, using ultraviolet ray/visible light to scan and measure its absorbency,using Gel permeation chromatography to purify LPS, using vitriol-phenol method to measure its content of sugar.LPS-liposomal was prepared by the method of reverse evaporation. The shape was observed under light microscope、transmission electron microscope, using laser light scattering to analyze its particle diameter distribution, using limulus test to evaluate its activity and stability,Using hundred times half lethal dose of bacteria or two times complete lethal dose of LPS or S180tumor cell to attack the mice immunized by the LPS-liposomal and record the results.ResultLPS is white wadding shape after freeze-dry by distillation,and has been identified.The liposomal Lipopolysaccharide was oyster white suspl in common temperature. It was multilayer round or oval saccule under the transmission electron microscope.Particle diameter was well-distributed about393.542±148.402nm.The endotoxic activities of LPS-lipopomal reduced100to1,000-fold compared with free LPS,which suggested99%-99.9%of the LPS had been incorporated into the liposomes.During the90-day stability experiments, there was no change in the LAL activity of any of these samples at any of the time points.The shape and particle diameter of LPS-lipopomal have no obvious change. Particle diameter has a little increase,it is432.475±155.148nm.After sigle lipopomal Lipopolysaccharide of Escherichia coli immuned,no matter what using hundred times lethal dose of bacteria or using two times complete lethal dose of LPS to attack the mice, experiment group’s survival rate and survival time are higher than control group.After mixed LPS-lipopomal of Escherichia coli immuned, TH1、TH1-LPS、 TH7、TH7-LPS group’s survival rate are all higher than control group. P7、K11、 P7-LPS、K11-LPS group’s survival rate have no distinct discrepancy compared to control group.After mixed lipopomal Lipopolysaccharide of TH1、P7、K11immuned, no matter what using hundred times lethal dose of bacteria or using two times complete lethal dose of LPS to attack the mice, TH1、TH7、P7group’s survival rate are all higher than control group.K11group’s survival rate and survival time have no distinct discrepancy compared to control group.After sigle LPS-lipopomal of Escherichia coli immuned,using tumor cell attack the mice, experiment group’s accont of tumor cell and ascites are less than control group,experiment group’s avoirdupois overweight control group.ConclusionThe method to prepare liposomal lipopolysaccharide is feasible.According to review the shape、particle diameter、LAL actity、envelop rate、stability and immunoprotection, the LPS-liposomal is stable in some condition low toxicity and has invariably immunoprotection to its strain or strain LPS attack, as well as has some immunoprotection to tumor cell’s attack.It is a hopeful approach for LPS-lipopomal to availablily prevent bacteria infection and tumor disease’s new method.