POLYVALENT VACCINE IN IL-2+GM-CSF LIPOSOMES FOR MELANOMA

我们的目标是开发一种强效的佐剂，这种佐剂可以强烈而安全地增强癌症疫苗的免疫原性。该建议是基于最近的观察，IL-2和GM-CSF可以单独增加疫苗的免疫原性，并且通过将细胞因子与疫苗一起共包被脂质体，每种细胞因子的佐剂活性显着增加。由于每种细胞因子通过不同的机制上调疫苗的免疫原性，因此两种细胞因子的结合应产生特别有效的佐剂。为了验证这一假设，我们建议进行一项随机II期试验来检验：1)与黑色素瘤疫苗一起共包被脂质体的IL-2+GM-CSF是否比单独使用任一细胞因子更能增强疫苗诱导的细胞免疫反应。切除的AJCC III期黑色素瘤HLA-A2（+）患者将随机接受多价脱落黑色素瘤抗原疫苗，该疫苗与IL-2或GM-CSF一起包裹在脂质体中，或同时使用两种细胞因子。疫苗诱导的CD8+ T细胞对源自MAGE-3、MART-1、gp100、酪氨酸酶和TRP-2的A-2限制性肽的应答程度将在基线和免疫后固定间隔用ELISPOT测定。2) IL-2+ GM-CSF脂质体是否能比单独使用任一细胞因子更强地增强疫苗诱导的抗体反应：采用Western免疫印迹法检测3组患者疫苗诱导的抗体对单个黑色素瘤抗原的反应。3)本治疗的安全性/副作用将遵循标准程序。该建议的主要优势在于，我们已经证明，IL-2脂质体和GM-CSF脂质体是人类单独有效的疫苗佐剂，我们已经确定了每种细胞因子的最佳剂量，当被装入脂质体时，可以最大限度地增强疫苗诱导的免疫反应，我们已经开发了足够敏感的检测方法，可以测量疫苗诱导的CD8+ T细胞和抗体对单个黑色素瘤抗原的反应。该疫苗含有多种黑色素瘤抗原，因此可以评估具有不同抗原的IL-2 + GM-CSF脂质体的佐剂活性。这项工作的成功完成将为提高黑色素瘤疫苗的有效性提供一种新方法，并可能导致改善这种癌症的一级和二级预防治疗。更广泛地说，它可以提供一种增强疫苗对其他癌症和传染病的免疫原性的一般方法。

Our goal is to develop a potent adjuvant that can strongly, but safely, boost the immunogenicity of cancer vaccines. The proposal is based on recent observations that IL-2 and GM-CSF can individually increase the immunogenicity of vaccines, and that the adjuvant activity of each cytokine is markedly increased by co-encapsulating the cytokine into liposomes together with the vaccine. As each cytokine upregulates vaccine immunogenicity by different mechanisms, the combination of both cytokines should result in a particularly potent adjuvant. To test this hypothesis, we propose to conduct a randomized phase II trial to examine: 1) Whether IL-2+GM-CSF co-encapsulated into liposomes together with a melanoma vaccine can increase vaccine-induced cellular immune responses more strongly than either cytokine alone. Patients with resected AJCC stage III melanoma who are HLA-A2(+) will be randomized to treatment with a polyvalent, shed melanoma antigen vaccine encapsulated into lipsomes together with IL-2 or GM-CSF, or with both cytokines. The magnitude of vaccine-induced CD8+ T cell responses to A-2 restricted peptides derived from MAGE-3, MART-1, gp100, tyrosinase and TRP-2 will be measured by ELISPOT at baseline and at fixed intervals following immunization. 2) Whether IL-2+ GM-CSF lipisomes can enhance vaccine-induced antibody responses more strongly than either cytokine alone: Vaccine-induced antibody responses in the 3 groups of patients will be measured to individual melanoma antigens by Western immunoblotting. 3)The safety of this treatment/ Side effects will be followed by standard procedures. Major strengths of this proposal are that we have already demonstrated that IL-2 liposomes and GM-CSF liposomes are individually potent vaccine adjuvants in humans, that we have determined the optimal doses of each cytokine that maximally enhance vaccine-induced immune responses when encapsulated into lipsomes, that we have developed assays that are sufficiently sensitive to measure vaccine-induced CD8+ T cell and antibody responses to individual melanoma antigens, and that the vaccine contains multiple melanoma antigens so that the adjuvant activity of IL-2 + GM-CSF liposomes with different antigens can be evaluated. Successful completion of this work will provide a new method to increase the effectiveness of melanoma vaccines, and may lead to an improved treatment for the primary and secondary prevention of this cancer. More broadly, it may provide a general method of potentiating the immunogenicity of vaccines against other cancers and to infectious diseases.