DESIGN OF LIVE RECOMBINANT VACCINES FOR ACTIVE SPECIFIC IMMUNOTHERAPY

正在进行的研究包括构建和临床前评价， 重组痘病毒的安全性和免疫原性 人肿瘤相关抗原。其中包括癌胚抗原 (CEA)前列腺特异性抗原（PSA）和人乳腺癌 抗原MUC 1。我们证明了CEA可以作为靶点， 主动特异性免疫治疗用重组体免疫小鼠 表达CEA的痘苗病毒（rV-CEA）能够诱导抗肿瘤活性， 活动表达PSA和MUC 1的重组牛痘病毒也被 发现是安全的疫苗，并引发适当的抗肿瘤 应答用rV-PSA免疫的恒河猴能够引起PSA-1， 特异性体液和细胞介导的免疫应答。各种 通过T细胞表面分子传递的共刺激信号是 携带抗原的靶细胞激活初始T细胞所需的 细胞B7基因家族的表达以及其他 共刺激分子，如CD 70、LFA 3和ICAM-1，已经显示出 作为引导和维持 实验模型中的抗肿瘤反应。我们建造了 评价了表达B7-1的重组牛痘病毒的能力， B7-2、CD 70、LFA 3和ICAM-1以在细胞内递送共刺激分子。 抗原呈递位点与增强细胞介导抗肿瘤 应答用rV-B7-1和B7-2和ICAM-1感染的肿瘤细胞 导致动物体内没有肿瘤生长，而肿瘤细胞感染 与野生型牛痘病毒接触导致肿瘤生长和死亡， 主持人这些研究证明了实用性和易用性 向肿瘤递送共刺激分子的重组牛痘病毒 用于潜在的基因治疗和癌症重组方法的细胞 免疫疗法我们还证明了混合这些物质的效用， 具有rV-CEA和rV-MUC 1的重组共刺激牛痘病毒， 增强肿瘤相关抗原特异性T细胞应答和抗肿瘤 小鼠肿瘤模型中的免疫力。T细胞免疫原性的改善 肿瘤相关抗原疫苗的特异性 通过构建重组牛痘病毒来完成， 肿瘤相关免疫显性表位的最小决定簇 抗原表达肿瘤相关基因的第二代疫苗 使用非复制型痘病毒， 禽痘、禽痘和MVA（改良安卡拉牛痘）。

Ongoing studies involve the construction and preclinical evaluation of the safety and immunogenicity of recombinant pox viruses expressing human tumor associated antigens. These include carcinoembryonic antigen (CEA), prostate specific antigen (PSA), and the human breast cancer antigen, MUC1. We demonstrated that CEA could be used as a target for active specific immunotherapy. Immunization of mice with a recombinant vaccinia virus expressing CEA (rV-CEA) was able to elicit antitumor activity. Recombinant vaccinia viruses expressing PSA and MUC1 were also found to be safe vaccines and to elicit the appropriate anti-tumor responses. Rhesus monkeys immunized with rV-PSA were able to elicit PSA- specific humoral as well as cell-mediated immune responses. Various costimulatory signals delivered through T-cell surface molecules are required for the activation of naive T-cells by antigen-bearing target cells. The expression of the B7 gene family as well as other costimulatory molecules, such as CD70, LFA3 and ICAM-1, have been shown to be an important component for the induction and maintenance of antitumor responses in experimental models. We have constructed and evaluated the ability of recombinant vaccinia viruses expressing B7-1, B7-2, CD70, LFA3 and ICAM-1 to deliver costimulatory molecules at the site of antigen presentation and enhance cell mediated anti-tumor responses. Tumor cells infected with rV-B7-1 and B7-2 and ICAM-1 resulted in no tumor growth in the animals, while tumor cells infected with wild type vaccinia virus led to tumor growth and the death of the host. These studies demonstrated the utility and ease of using recombinant vaccinia viruses to deliver costimulatory molecules to tumor cells for potential gene therapy and recombinant approaches to cancer immunotherapy. We have also demonstrated the utility of admixing these recombinant costimulatory vaccinia viruses with rV-CEA and rV-MUC1 to enhance tumor associated antigen-specific T-cell responses and antitumor immunity in murine tumor models. Improvement of T-cell immunogenicity and specificity of tumor associated antigen vaccines has been accomplished by constructing recombinant vaccinia viruses containing minimal determinants of an immunodominant epitope of tumor associated antigens. Second generation vaccines expressing tumor associated antigens are being developed using nonreplicating pox viruses such as avipox, fowl pox and MVA (Modified Vaccinia Ankara).