基于重组α-病毒的基因疫苗对小鼠肥大细胞瘤P815的防治作用

Preventive and therapeutic effect of genetic vaccine based on recombinant alpha virus against mouse mastocytoma P815

目的 :探讨基于α 病毒的基因疫苗的免疫学效应作用 ,寻找更好的基因疫苗形式。方法 :用磷酸钙法共转染表达质粒P1A/pSMART2a和包装质粒helper到 2 93细胞中 ,制备高水平的重组α 病毒P1A/SFV。鉴定病毒及其表达后 ,用其免疫小鼠 ,测定免疫动物体内抗体生成情况和特异CTL的杀伤效应。在预防性和治疗性实验中 ,测定该重组病毒免疫动物后6 0d内动物的无瘤率和生存率。结果 :该重组病毒疫苗在体外培养细胞中有很好的表达。用其免疫动物后 ,P1A/SFV能激发比对照组强得多的CTL杀伤效应。在E/T比为 10 0∶1时 ,P1A/SFV组CTL的杀伤率为 75 %。抗体在所有组别中均未见产生。在保护性和治疗性实验中 ,于 6 0d实验期限内 ,P1A/SFV的效果最好。保护性实验第 6 0天时 ,P1A/SFV组动物的无瘤率达到 6 0 % ;而P1A/ pCI neo组只有2 0 %。在治疗性实验第 6 0天 ,P1A/SFV组小鼠的存活率达到 5 0 %左右 ;而其他对照组都只有 10 %左右。结论 :相对于普通基因疫苗 ,基于重组α 病毒的基因疫苗效果最好 。

AIM: To explore the immunological effect of genetic vaccine based on α-virus and to seek out better forms of gene vaccines. METHODS: Expression plasmid P1A/pSMART2a and packaging plasmid helper were cotransfected into mammalian 293 cells by calcium phosphate precipitation method and high level of recombinant α-virus P1A/SFV was prepared. Following identification of rSFV and its expression, BALB/c mice were inoculated with rSFV, and the production of antigen-specific antibody and the cytotoxic effect of CTLs were determined. In the preventive and therapeutic experiments, the percents of tumor-free and of survival mice immunized with rSFV were observed. RESULTS: The recombinant SFV could express correctly in cultured cells. After being inoculated into the mice, rSFV could prime stronger CTL response than that in control mice. When the ratio of E/T cells was 100∶1, the 51Cr release rate reached 75%. No antibody could be detected in mice from all groups. The immunological effect of P1A/SFV among all groups was the best in both preventive and therapeutic experiment within experimental deadline. On 60th day in preventive experiment, the percent of tumor-free animal in P1A/SFV group reached 60%, whereas that was only 20% in P1A/pCI-neo group. On 60th day in therapeutic experiment, survival rate of mice in P1A/SFV group reached 50%, but only 10% mice could survive in all control groups. CONCLUSION: Compared with common gene vaccines, the genetic vaccine based on recombinant SFV has the best immunological effect, which provides some new strategies for clinical genetic therapy of tumors.