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目的观察IL-2基因佐剂与梅毒螺旋体(Treponema pallidum,Tp)膜蛋白Tp92抗原编码基因DNA疫苗联合免疫新西兰兔后对Tp皮肤感染的免疫保护效果。方法将体重约3kg的新西兰兔随机分为pcDNA3.1(+)/IL-2+pcDNA3.1(+)/Tp92联合免疫组,pcDNA3.1(+)/Tp92免疫组,pcDNA3.1(+)空质粒组及PBS空白组共4组,每组18只,每隔2周免疫一次,共免疫3次,初次免疫后第10周进行Tp皮肤感染,观察并记录感染早期各组家兔皮损情况;ELISA检测感染后不同时间点免疫兔血清特异性抗体水平和脾细胞IL-2及IFN-γ水平;MTT法检测感染后不同时间点兔脾淋巴细胞增殖水平。结果 IL-2+Tp92DNA疫苗联合免疫组在Tp感染后0～224d期间的不同时间点均检测到高滴度的特异性IgG,与Tp92DNA疫苗组及各对照组比较差异均有统计学意义(P<0.05);感染后第14d联合免疫组兔脾细胞培养上清中IFN-γ和IL-2水平均显著高于Tp92单独免疫组(P<0.05)及空质粒对照组和空白对照组(P<0.01),感染后不同时间点兔脾细胞均有明显增殖反应,SI值显著高于同期Tp92单独免疫组(P<0.05)及空质粒对照组和空白对照组(P<0.01)。Tp感染早期联合免疫组家兔皮损Tp阳性率为20%,溃疡病灶形成率为10%,皮损愈合时间为48d。结论 IL-2基因佐剂和Tp92DNA联合免疫能有效地诱导新西兰兔在Tp感染期间产生稳定持久保护性免疫应答,并能阻止Tp皮肤感染部位病损的发展。
Objective To observe the protective effect of IL-2 gene adjuvant and Treponema pallidum (Tp) membrane protein Tp92 antigen-encoding DNA vaccine on New Zealand rabbits immunized with Tp skin infection. Methods New Zealand rabbits weighing about 3 kg were randomly divided into pcDNA3.1 (+) / IL-2 + pcDNA3.1 (+) / Tp92 combined immunization group, pcDNA3.1 (+) / Tp92 immunization group, pcDNA3.1 ) Empty plasmid group and PBS blank group were divided into 4 groups (n = 18), immunized once every 2 weeks with three immunizations. Tp skin infection was performed 10 weeks after the first immunization. Rabbits skin The levels of IL-2 and IFN-γ in serum were detected by ELISA at different time points after infection. The proliferation of spleen lymphocytes was detected by MTT assay at different time points after infection. Results High titers of specific IgG were detected at different time points between 0 and 224 days after Tp infection in IL-2 + Tp92 DNA vaccine combined immunization group, and there was significant difference compared with Tp92 DNA vaccine group and each control group (P <0.05). The levels of IFN-γ and IL-2 in the supernatant of splenocytes from the 14th day after infection were significantly higher than those from Tp92 alone immunized group (P <0.05) and blank plasmid control group (P <0.05). The SI value was significantly higher than that of the Tp92 alone immunized group (P <0.05) and the empty plasmid control group and the blank control group (P <0.01) at different time points after infection. The positive rate of Tp in skin lesions of rabbits with early Tp infection was 20%, the incidence of ulcer lesions was 10%, and the healing time of skin lesions was 48 days. Conclusion Combined immunization with IL-2 gene adjuvant and Tp92 DNA can effectively induce New Zealand rabbits to produce stable and long-lasting protective immune response during Tp infection and prevent the development of lesion in Tp skin infection.