Comparison of the Effects of ILO and LLO in Helping Listeria Adhere,Invade Cell and Intracellularly Multiply

ObjectiveTo study the primary function of ivanolysin O (ILO) and Listeriolysin O (LLO) and compare the effects of these two hemolysins in helping bacteria adhere,invade cell and intracellularly multiply. MethodsThe targeting plasmids carrying the upstream and downstream sequences of i-hly and lacZ gene sequence or hly gene sequence were constructed. Then two recombinant strains,the ILO deletion strain LIΔi-hly∷lacZ and LLO compensative expressing strain LIΔi-hly∷hly,were constructed by plasmid targeting recombinant technique. The adhesive and invasive ability of LIΔi-hly∷hly,LI and LIΔi-hly∷lacZ were evaluated in HepG2 cells,and their intracellular multiplication abilities were evaluated in RAW264.7 macrophages. ResultsGenome sequences of the recombinant strains were as expected. The adhesive rate of LIΔi-hly∷hly,LI and LIΔi-hly∷lacZ were (3.43±0.82)%,(3.43±1.59)% and (3.41±1.12)% respectively,and the invasive rate were (1.74±0.46)%,(1.22±0.75)% and (1.39±0.46)% respectively. Difference in adhesive and invasive rates showed no significance. Among three strains,LIΔi-hly∷lacZ showed the lowest intracellular proliferation rate,and LIΔi-hly∷hly possessed the highest intracellular proliferation rate in RAW264.7 macrophages. ConclusionThe intracellular multiplication ability of LI is related to ILO. Deletion of ILO induces a distinct decrease in intracellular multiplication for LI. Compared with ILO,LLO shows a stronger ability in helping the bacteria escape from the phagosome into the host cell cytosol.