Extrinsic C5a Activation Regulates Squamous Carcinogenesis and Limits Clonal T Cell Responses to Chemotherapy (Skin)

In the K14-HPV16 transgenic mouse model of squamous carcinogenesis, activation of C5a receptor (C5aR1) in early neoplastic tissues fosters protumorigenic properties of C5aR1+ mast cells and macrophages, and in turn, suppression of CD8+ T cell cytotoxicity. Therapeutic inhibition of C5a receptor (C5aR1) with a peptide antagonist improved efficacy to paclitaxel chemotherapy associated with CXCR3-dependent CD8+ T cell activation. To investigate the effects of combination therapy on the T cell repertoire, we performed deep sequencing of the complementarity-determining region (CDR) 3 of the T cell receptor (TCR)b chain in matched tumor lysates and peripheral blood mononuclear cells (PBMCs). Intratumoral TCRß clonotypes were hyperexpanded and increasingly detected in matched peripherally-expanded T cell populations, thereby implicating antigen-dependent peripheral priming in response to systemic C5aR1 inhibition. Overall design: Deep sequencing of the complementarity-determining region (CDR) 3 of the T cell receptor (TCR)b chain in matched tumor lysates and peripheral blood mononuclear cells (PBMCs)

在鳞状细胞癌变的K14-HPV16转基因小鼠模型中，早期肿瘤组织内C5a受体（C5a receptor, C5aR1）的激活可促进C5aR1阳性肥大细胞与巨噬细胞的促肿瘤特性，进而抑制CD8+T细胞的细胞毒性。采用肽拮抗剂对C5a受体进行治疗性阻断，可提升紫杉醇化疗的疗效，该效应与依赖CXCR3的CD8+T细胞活化相关。为探究联合治疗对T细胞受体库的影响，我们对配对的肿瘤裂解液与外周血单个核细胞（peripheral blood mononuclear cells, PBMCs）中的T细胞受体（T cell receptor, TCR）β链互补决定区（complementarity-determining region, CDR）3进行了深度测序。研究发现，肿瘤内的TCRβ克隆型呈现过度扩增状态，且在配对的外周扩增T细胞群中检出率逐渐升高，这表明系统性C5aR1阻断可触发抗原依赖性外周致敏过程。实验整体设计：对配对的肿瘤裂解液与外周血单个核细胞（PBMCs）中的T细胞受体（TCR）β链互补决定区（CDR）3进行深度测序。