布鲁氏菌A19株菌影疫苗的构建及其免疫效果评价OA北大核心

In order to develop a safe and effective Brucella vaccine,addressing the challenges associated with existing weak vaccines like A19,S2,and M5,which exhibit strong virulence and can infect humans,and that their immune antibodies cannot be discriminatively differentiated from those of the wild virulent infections by serological methods.A bacterial ghost vaccine(A19-BG)strain was constructed by transforming a plasmid containing lytic enzyme gene E of the bacteriophage PhiX174 into the A19 vaccine strain,and its genetic stability and safety,immune effects and protective effects in mice were examined.The results showed that the constructed A19-BG strain remained stable after 20 passages,and was completely inactivated after 48 hours of heat induction,with obvious perforation of the bacterial body.Mice immunized with A19-BG showed no adverse reactions at the immunization site after 7 days,and no visible pathological changes in the spleen after 14 days.There were no significant differences in spleen weight compared with the blank control group(P>0.05).Fourteen days after the first and second immunizations,the levels of Brucella antibodies,interleukin-4(IL-4),and γ interferon(IFN-γ)levels in immunized mice continued to rise,indicating good humoral and cellular immune response.When challenged mice with the virulent Brucella 2308 strain,the immunization protection rate reached 87.5%,demonstrating excellent protective effects.The results indicate that the constructed A19-BG vaccine exhibits good stability,safety,immune effects,and protective effects,making it a promising novel Brucella vaccine.