Project 3: Chemokine modulation in TME for enhanced TLS formation and cross-priming/ recruitment of therapeutic CD8+ TILs

摘要 趋化因子（CK）在免疫细胞向癌组织的募集中起关键作用。进展性肿瘤 通常以局部产生调节性趋化因子（CKs）和抑制细胞为特征， 促炎性CK的产生募集保护性CTL和Th 1细胞、树突状细胞（DC）和NK细胞， 肿瘤微环境（TME）与有效的（免疫）治疗干预。我们有 最近显示，靶向肿瘤血管抗原（TVA）的联合疫苗促进特异性CD 8 + T细胞 细胞应答和基质CCL 5/CXCL 9 -11产生的协同上调以及治疗性T细胞 TME中的CCL 22/CXCL 12产生和MDSC/Treg含量的降低。治疗还 促进TME中CCR 7-配体CKs CCL 19/CCL 21的从头产生，以及三级细胞的发展。 淋巴样结构（TLS）。值得注意的是，给予自体α DC 1/TVA肽基疫苗， 达沙替尼治疗免疫检查点阻断（ICB）难治性晚期黑色素瘤患者 （NCT 01876212）在13例可评价患者中的6例（46%）中产生了客观临床获益，包括7例中的4例 (57%）表现出对抗PD 1阻断疗法的原发性耐药的患者。TCRBseq分析显示， 在治疗诱导的TIL库中的TCR会聚（即免疫焦点）在目标之前增加 临床反应。此外，临床应答者在治疗后表现出独特的TIL克隆型， 在血液中可检测到，支持TME作为治疗依赖性T细胞交叉致敏的相关位点， “表位扩散”。由于在小鼠B16黑色素瘤模型中的新的初步数据表明， 当与项目1开发的CK调节组合时，基于α DC 1/TBVA的疫苗的效力是优越的上级 (CKM)方案与达沙替尼，项目3，我们将测试的假设， 基于α DC 1/血管肽的免疫治疗免疫检查点抑制剂（ICI）难治性晚期 当与趋化因子调节方案（包括CKM）组合时，黑色素瘤患者将增加， 具体而言，我们将进行1型极化树突状细胞（α DC 1）/TVA肽疫苗接种的I/II期试验 联合肿瘤选择性趋化因子调节（CKM：干扰素-α2b、Rintatolimod和塞来昔布） 原发性PD-1/PD-L1耐药的晚期HLA-A2+黑色素瘤患者（Aim 1），并分析 治疗期间患者TME和血液的变化，以确定免疫学的临床相关变化 分析物（目标2）。然后将进行动物建模以确定疫苗形式在免疫中的作用。 基于CKM的免疫疗法+/-免疫调节拮抗剂组合的治疗功效（目的3）。

ABSTRACT Chemokines (CK) play critical roles in the recruitment of immune cells into cancer tissues. Progressing tumors are commonly characterized by local production of regulatory chemokines (CKs) and suppressor cells, while production of pro-inflammatory CKs recruits protective CTLs and Th1 cells, dendritic cells (DC) and NK cells into the tumor microenvironment (TME) in association with effective (immuno)therapeutic intervention. We have recently shown that a combination vaccine targeting tumor vascular antigens (TVA) promotes specific CD8+ T cell responses and the coordinate upregulation of stromal CCL5/CXCL9-11 production and therapeutic T cell infiltration, and reduction in CCL22/CXCL12 production and MDSC/Treg content in the TME. Treatment also promotes de novo production of CCR7-ligand CKs CCL19/CCL21 in the TME, and the development of tertiary lymphoid-like structures (TLS). Remarkably, an autologous αDC1/TVA peptide-based vaccine administered with dasatinib to immune checkpoint blockade (ICB)-refractory patients with advanced-stage melanoma (NCT01876212) resulted in objective clinical benefit in 6 of 13 (46%) evaluable patients overall, including 4 of 7 (57%) patients exhibiting primary resistance to anti-PD1 blockade therapy. TCRBseq analyses revealed increased TCR convergence (i.e. immune focus) in the therapy-induced TIL repertoire in advance of objective clinical response. Furthermore, clinical responders exhibited unique TIL clonotypes post-treatment that were not detectable in blood, supporting the TME as a relevant site for treatment-dependent T cell cross-priming and “epitope spreading”. Since new preliminary data in murine B16 melanoma models suggests that therapeutic efficacy of αDC1/TBVA-based vaccines is superior when combined with the Project 1-developed CK modulation (CKM) regimen vs. dasatinib, Project 3, we will test the hypothesis that therapeutic benefits resulting from αDC1/vascular peptide-based immunotherapy in immune checkpoint inhibitor (ICI)-refractory, advanced-stage melanoma patients will be increased when combined with chemokine-modulating regimens (including CKM), Specifically, we will perform a Phase I/II trial of Type-1-polarized dendritic cell (αDC1)/TVA peptide vaccination in combination with tumor-selective chemokine modulation (CKM: Interferon-α2b, Rintatolimod and Celecoxib) in advanced-stage HLA-A2+ melanoma patients with primary PD-1/PD-L1 resistance (Aim 1) and analyze the on-treatment changes in TME and blood of patients to determine clinically-relevant changes in immunological analytes (Aim 2). Animal modeling will then be performed to determine the role of vaccine format in the therapeutic efficacy of combination CKM-based immunotherapy +/- immune regulatory antagonists (Aim 3).