MUC1基因疫苗诱导小鼠特异性CTL和体液免疫应答

目的 :观察MUC1基因疫苗诱导小鼠特异性杀伤性T细胞及体液免疫应答的作用。方法 :采用股四头肌肌肉注射 ,将构建的MUC1基因疫苗pcDNA3.1 MUC1免疫雌性BALB/c小鼠 ,每次间隔 3wk ,共 3次。最后 1次免疫后第 3周 ,接种表达MUC1的EMT6乳腺癌细胞进行免疫保护实验。用 4h51Cr释放法检测小鼠脾细胞特异性CTL杀伤活性 ;免疫组化染色法检测小鼠血清特异性抗体的水平。结果 :在效靶比为 10 0∶1、5 0∶1、2 5∶1、12 .5∶1时 ,MUC1基因疫苗免疫组特异性CTL对EMT6靶细胞杀伤活性分别为 5 4 .1%、39.8%、2 6 .4 %和2 0 .1% ,对照组分别为 13.2 %、10 .0 %、8.2 %、7.2 %和 11.7%、9.8%、7.7%、7.0 % ,前者与后二者差异显著 (P <0 .0 1)。免疫组化染色检测显示 ,人乳腺癌组织MUC1呈染色阳性 ;MUC1基因疫苗免疫组仅见 4 0 % (4/ 10 )的小鼠有肿瘤形成 ,而 pcDNA3.1对照组和生理盐水阴性对照组 10 0 %可见肿瘤形成、生长 ,表明MUC1基因疫苗免疫组小鼠具有一定的免疫保护作用。结论 :MUC1基因疫苗可诱导小鼠产生特异性CTL及体液免疫应答 ,对小鼠体内荷瘤可能具有一定的预防作用

Induction of specific cytotoxic T lymphocytes and humoral immune response by MUC1 DNA vaccine in mice

AIM: To observe the specific cytotoxic T lymphocyte and humoral immune response induced by MUC1 DNA inmunization in mice. METHODS: Female BALB/c mice were immunized intramuscularly with 100 microg pcDNA3.1-MUC1 3 times at intervals of 3 weeks. Three weeks after the last immunization, tumor challenge experiments were performed by inoculation of MUC1 positive breast cancer cell line EMT6. Both humoral immune response and CTL-specific cytotoxicity were detected by immunohistochemical staining and (51)Cr release assay, respectively. RESULTS: The cytotoxicity of MUC1-specific CTLs to EMT6 target cells showed that the cytotoxic effect was different at various ratio of effector cells to target cells. At ratios of 100:1, 50:1, 25:1 and 12.5:1, the specific lysis in MUC1cDNA group reached 54.1%, 39.8%, 26.4% and 20.1%, while two control groups 13.2%, 10%, 8.2%, 7.2% and 11.7%, 9.8%, 7.7%, 7.0%, respectively. The former was markedly higher than the two latters(P<0.01). MUC1 expression was exhibited to be positive in breast cancer tissue by immunohistochemical staining with BALB/c mouse sera against MUC1 cDNA. There was only 40% tumorigenic rate in MUC1 cDNA immunized group, while there 100% in pcDNA3.1(+) and NS control groups. There was a significant difference between MUC1 cDNA group and control groups (P<0.05). CONCLUSION: Specific CTLs and antibody prodution are elicited by MUC1 DNA inmunization. MUC1 cDNA inmunization partly inhibit the growth of implanted tumor in mice.