Novel target antigens for ovarian cancer immunotherapy

描述（申请人提供）：三分之二的卵巢癌患者在诊断时已处于晚期，卵巢癌是妇科恶性肿瘤中死亡率最高的。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。我们发现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，角质层凝乳胰蛋白酶（SCCE），它们都是丝氨酸蛋白酶，基质金属蛋白酶，泵-1。这些抗原在卵巢癌中高表达，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）免疫治疗的优秀靶抗原。本研究将验证抗原或肽负载DC可诱导卵巢癌患者特异性T淋巴细胞反应，肿瘤抗原特异性CTL可溶解卵巢肿瘤细胞的假设。我们已经证明，肽负载DC刺激HLA- i类限制性CDS+ CTL，裂解抗原表达靶标，包括HLA匹配的卵巢肿瘤细胞。第一个特异性目标将进一步鉴定CTL表位，并确定dc刺激的卵巢癌患者的肽特异性CD8+ CTL是否会溶解卵巢肿瘤细胞。我们还将测试用新型HLA I类单链三聚体转染DC是否会诱导肽特异性CD8+ CTL反应。在第二个特异性目标中，我们将构建包含定义的CTL表位和具有退化HLA II类结合潜力的候选CD4+辅助T细胞表位的肽。负载多表位肽的DC将被测试其诱导抗原特异性CD8+ CTL反应和CD4+辅助T细胞反应的能力。这种策略的基本原理是抗原特异性CD4+ T细胞在体内为诱导和维持有效的CD8+ T细胞反应提供了必要的帮助。我们还将测试从最近发现的表达变体hepsin和TADG-14的内含子序列翻译的肽的免疫原性。第三个特异性目标将确定DC是否加载全长重组肿瘤抗原或转染线性DNA构建物诱导卵巢癌患者的CD8+ CTL和CD4+ T细胞反应。本提案旨在制定临床试验方案，以治疗性DC疫苗预防卵巢癌进展。

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.