Novel target antigens for ovarian cancer immunotherapy

描述（由申请人提供）：三分之二的卵巢癌患者在诊断时患有晚期疾病，卵巢癌在妇科恶性肿瘤中死亡率最高。基于诱导肿瘤特异性细胞毒性T淋巴细胞（CTL）反应的免疫治疗可能是这些患者的一个有吸引力的选择。我们已经鉴定了一系列新的卵巢肿瘤抗原，包括肿瘤相关差异表达基因14（TADG-14）产物、TADG-15、hepsin、角质层胰凝乳蛋白酶（SCCE）（所有这些都是丝氨酸蛋白酶）和基质金属蛋白酶pump-1。这些抗原在卵巢癌中高度表达，但在正常卵巢或大多数其他正常成人组织中不表达，这表明它们可能是树突状细胞（DC）免疫治疗的优良靶抗原。该方案将验证负载抗原或肽的DC可用于诱导卵巢癌患者的特异性T淋巴细胞应答以及肿瘤抗原特异性CTL将裂解卵巢肿瘤细胞的假设。我们已经证明，负载肽的DC刺激HLA I类限制性CDS+ CTL，其裂解抗原表达靶，包括HLA匹配的卵巢肿瘤细胞。第一个特异性目的将鉴定进一步的CTL表位，并确定DC刺激的肽特异性CD 8 + CTL是否裂解卵巢癌患者的卵巢肿瘤细胞。我们还将测试是否DC转染新的HLA I类单链三聚体诱导肽特异性CD 8 + CTL反应。在第二个特定目标中，我们将构建包含定义的CTL表位和具有简并HLA II类结合潜力的候选CD 4+辅助T细胞表位的肽。将测试负载有多表位肽的DC诱导抗原特异性CD 8 + CTL应答和CD 4+辅助T细胞应答的能力。这种策略的基本原理是抗原特异性CD 4 + T细胞为体内有效的CD 8 + T细胞应答的诱导和维持提供了必要的帮助。我们还将测试从最近发现的在变体hepsin和TADG-14中表达的内含子序列翻译的肽的免疫原性。第三个特定目标将确定负载全长重组肿瘤抗原或转染线性DNA构建体的DC是否诱导卵巢癌患者的CD 8 + CTL和CD 4 + T细胞应答。该提案旨在开发用于预防卵巢癌进展的治疗性DC疫苗接种的临床试验方案。

DESCRIPTION (provided by applicant): Two-thirds of ovarian cancer patients have advanced disease at the time of diagnosis, and ovarian cancer has the highest mortality rate among gynecological malignancies. Immunotherapy based on induction of tumor-specific cytotoxic T lymphocyte (CTL) responses may represent an attractive option for these patients. We have identified a series of novel ovarian tumor antigens, including the tumor-associated differentially expressed gene 14 (TADG-14) product, TADG-15, hepsin, stratum corneum chymotryptic enzyme (SCCE), all of which are serine proteases, and the matrix metalloprotease, pump-l. These antigens are highly expressed in ovarian cancer but not in normal ovaries or the majority of other normal adult tissues, suggesting that they may be excellent target antigens for dendritic cell (DC) immunotherapy. This proposal will test the hypothesis that antigen or peptide-loaded DC can be used to induce specific T lymphocyte responses from patients with ovarian cancer, and that tumor antigen-specific CTL will lyse ovarian tumor cells. We have shown that peptide-loaded DC stimulate HLA class I-restricted CDS+ CTL that lyse antigen-expressing targets, including HLA-matched ovarian tumor cells. The 1st Specific Aim will identify further CTL epitopes and determine whether DC-stimulated peptide-specific CD8+ CTL from ovarian cancer patients lyse ovarian tumor cells. We will also test whether DC transfected with novel HLA class I single chain trimers induce peptide-specific CD8+ CTL responses. In the 2nd Specific Aim, we will construct peptides that encompass defined CTL epitopes and candidate CD4+ helper T cell epitopes with degenerate HLA class II binding potential. DC loaded with multi-epitope peptides will be tested for their ability to induce antigen-specific CD8+ CTL responses and CD4+ helper T cell responses. The rationale for this strategy is that antigen-specific CD4+ T cells provide essential help for the induction and maintenance of effective CD8+ T cell responses in vivo. We will also test the immunogenicity of peptides translated from recently discovered intron sequences expressed in variant hepsin and TADG-14. The 3rd Specific Aim will determine whether DC loaded with full-length recombinant tumor antigen or transfected with linear DNA constructs induce CD8+ CTL and CD4+ T cell responses from ovarian cancer patients. This proposal is targeted at the development of clinical trial protocols for therapeutic DC vaccination for prevention of progression of ovarian cancer.