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目的研究单独及联合应用Ag85A与Ag85B DNA疫苗对膀胱肿瘤的免疫效应。方法选择6~8周龄雌性Wistar大鼠作为实验对象。以膀胱灌注MNU建立膀胱原位癌模型,左后肢皮下注射BTT739细胞株建立种植性膀胱肿瘤模型。于末次膀胱灌注后14 d随机处死10只大鼠,以确定模型是否成功建立。每种模型均随机分为6组(每组8只):生理盐水(NS)组、pcDNA3.1组(空白质粒组)、pcDNA3.1-Ag85A(Ag85A)组、pcDNA3.1-Ag85B(Ag85B)组、pcDNA3.1-Ag85A+Ag85B组(联用组)、卡介苗(BCG)组,并予相应干预治疗。计算各组肿瘤生长抑制率、荷瘤鼠脾脏T细胞亚群数量变化,检测血清干扰素(IFN)-γ水平,剥离肿瘤进行病理组织学检查。结果肿瘤生长抑制率:BCG组最高达63.53%,其余依次为联用组53.56%、Ag85B组33.08%、Ag85A组11.50%、空白质粒组1.10%;干预治疗后空白质粒组T细胞亚群无明显变化,其余各组CD4+T细胞与CD8+T细胞亚群的数量及CD4+/CD8+比值均有增加(P<0.05或P<0.01);空白质粒组血清IFN-γ水平无变化,BCG组升高最明显,其余依次为联用组、Ag85B组、Ag85A组。病理组织学观察显示BCG组、联用组、Ag85B组肿瘤坏死明显,而Ag85A组、NS组和空白质粒组肿瘤坏死不明显。结论Ag85A与Ag85B DNA疫苗对大鼠原位及种植性膀胱癌有明显的免疫效应,Ag85B DNA疫苗的免疫效力强于Ag85A DNA疫苗;两者联用效果更显著,但不及BCG的抗肿瘤效果。
Objective To study the immune effect of Ag85A and Ag85B DNA vaccines on bladder tumors alone and in combination. Methods Six to eight-week-old female Wistar rats were selected as experimental subjects. In situ bladder cancer model was established by intravesical instillation of MNU, and BTT739 cell line was injected subcutaneously into the left hind limb to establish a model of implantable bladder tumor. Ten rats were randomly sacrificed at 14 days after the last intravesical instillation to determine if the model was successfully established. Each model was randomly divided into 6 groups (n = 8): NS group, pcDNA3.1 group (blank plasmid group), pcDNA3.1-Ag85A (Ag85A) group, pcDNA3.1-Ag85B ) Group, pcDNA3.1-Ag85A + Ag85B group (combined group) and BCG group, and corresponding intervention treatment. The growth inhibition rate of each group was calculated, the number of T lymphocyte subsets in the spleen of the tumor-bearing mice was changed, the level of serum IFN-γ was detected, and the tumor was dissected for histopathological examination. Results The rate of tumor growth inhibition was up to 63.53% in BCG group, followed by 53.56% in combination group, 33.08% in Ag85B group, 11.50% in Ag85A group and 1.10% in blank plasmid group. The T cell subpopulation in blank plasmid group was not significant after intervention (P <0.05 or P <0.01). The levels of IFN-γ in the blank plasmid group did not change, but the levels of CD4 + T cells and CD8 + T cells in the other groups were increased The most obvious high, the rest followed by combination group, Ag85B group, Ag85A group. Histopathological examination showed that tumor necrosis was obvious in BCG group, combination group and Ag85B group, while tumor necrosis in Ag85A group, NS group and blank plasmid group was not obvious. Conclusions Ag85A and Ag85B DNA vaccines have significant immunologic effect on orthotopic and implanted bladder cancer in rats. The immunogenicity of Ag85B DNA vaccine is stronger than that of Ag85A DNA vaccine. The combination of Ag85A and Ag85B DNA vaccine is more effective than BC85 but less effective than BCG in anti-tumor effect.