Recombinant E.coli LLO/OVA Vaccination Effectively Inhibits Murine Melanoma Metastasis to Lung by CD8+T Cells Immunity

摘要

Objective: To construct recombinant E.coli LLO/OVA and investigate its tumor metastatic inhibition effect in B16 OVA melanoma challenged mice.Methods: Recombinant E.coli LLO/OVA was constructed and the expression of listeriolysin O (LLO) and ovalbumin (OVA) of the vaccine was determined by coomassie brilliant blue staining and western blotting. After 3 subcutaneous injections of E.coli LLO/OVA, the percentages of CD3+CD4+T, CD4+CD25+T, CD3+CD8+T and OVA257(264 SIINFEKL specific CD8+T cells were determined by flow cytomytry, and the tumor metastatic inhibition effect in B16 OVA melanoma challenged mice was observed.Results: Recombinant E.coli LLO/OVA was successfully constructed, and the expression of LLO and OVA of the vaccine was confirmed. After 3 subcutaneous injections of E.coli LLO/OVA and E.coli OVA in mice, the percentages of CD3+CD4+T, CD4+CD25+T and CD3+CD8+T cells were equivalent in the two groups of mice. However, there were significantly more OVA257(264 SIINFEKL specific CD8+T cells in E.coli LLO/OVA vaccinated mice than that in E.coli OVA vaccinated mice. The prophylactic E.coli LLO/OVA vaccination effectively prevented the tumor metastasis to lungs in B16 OVA melanoma challenged mice. Depletion of CD8+T cells significantly impaired the tumor inhibition effect of the vaccine in B16 OVA challenged mice. The therapeutic vaccination of E.coli LLO/OVA significantly prevented melanoma metastasis to lungs in B16 OVA challenged mice too.Conclusion: Recombinant E.coli LLO/OVA vaccination is highly effective in inhibiting murine malignant melanoma metastasis by promoting CD8+T cell immunity.