DESIGN OF LIVE RECOMBINANT VACCINES FOR ACTIVE SPECIFIC IMMUNOTHERAPY

正在进行的研究包括建造和评估安全性和 表达人肿瘤的重组痘病毒的免疫原性 相关抗原。这些包括癌胚抗原(CEA)和 前列腺特异性抗原(PSA)。我们演示了CEA可以用于 作为主动特异性免疫治疗的靶点。小鼠的免疫 用表达CEA的重组痘苗病毒(RV-CEA)能够 激发抗肿瘤活性。其他与肿瘤相关的抗原 代表肿瘤靶点的是人类粘蛋白基因家族的成员，如 如MUC1和MUC2，在这些品种中基因表达上调 上皮性癌症，如乳腺癌、结直肠癌、卵巢癌和肺癌。 粘蛋白基因家族成员的遗传结构复杂。 它们包含100-150个高度重复的核苷酸区域的DNA片段 60-120个碱基对(VNTR可变数目串联重复)。VNR是 在痘苗病毒中不稳定。一种稳定的重组痘苗病毒 表达MUC1的方法是将VNTR区域截断为 仅包含10个VNR。这种疫苗被证明能诱导出特定的MUC1 转移性小鼠的体液、细胞和抗肿瘤反应 肿瘤模型。T细胞传递的各种共刺激信号 表面分子是激活幼稚T细胞所必需的 携带抗原的靶细胞。B7基因家族的表达 以及其他共刺激分子，如CD70、LFA3和ICAM-1 已经被证明是诱导的一个重要组成部分 在实验模型中维持抗肿瘤反应。我们有 重组痘苗病毒的构建和鉴定 B7.1和ICAM-1。RV-B7.1感染的肿瘤细胞未见肿瘤 肿瘤细胞感染野生型时在动物体内生长 牛痘病毒可导致宿主死亡。这些研究 演示了使用重组痘苗病毒的实用性和易用性 向肿瘤细胞递送共刺激分子寻找潜在基因 癌症免疫治疗和重组方法。我们有 也证明了混合这些重组基因的效用 共刺激痘苗病毒与RV-CEA和RV-MUC1联合增强 小鼠肿瘤特异性T细胞反应与抗肿瘤免疫 模特们。提高T细胞免疫原性和肿瘤特异性 相关抗原疫苗已经通过构建 含有最小决定因素的重组痘苗病毒 肿瘤相关抗原的免疫优势表位。第二代 正在使用非复制型痘病毒开发疫苗，例如 禽痘、鸡痘和MVA(改良痘苗)。

Ongoing studies involves constructing and evaluating the safety and immunogenicity of recombinant pox viruses expressing human tumor associated antigens. These include carcinoembryonic antigen (CEA) and prostate specific antigen (PSA). 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 anti-tumor activity. Other tumor associated antigens that represent tumor targets are members of the human mucin gene family such as MUC1 and MUC2 in which gene expression is upregulated in a variety of epithelial cancers such as breast, colorectal, ovarian, and lung. The mucin gene family members are complex in their genetic structure. They contain 100-150 DNA segments of highly repeated nucleotide regions of 60-120 base pairs (VNTR variable number tandem repeats). VNTRs are unstable in vaccinia viruses. A stable recombinant vaccinia virus expressing MUC1 was constructed by truncating the VNTR region to contain only 10 VNTRs. This vaccine was shown to elicit specific MUC1 humoral, cell mediated and anti-tumor responses in a metastatic murine tumor model. 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 anti-tumor responses in experimental models. We have constructed and characterized recombinant vaccinia viruses containing B7.1 and ICAM-1. Tumor cells infected with rV-B7.1 resulted in no tumor growth in the animals while tumor cells infected with wild type vaccinia virus lead to 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 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 are being developed using nonreplicating pox viruses such as avipox, fowlpox, and MVA (modified vaccinia ankra).