Tumor-Specific MHC-II Activates CD4+ and CD8+ T Cells in Head and Neck Squamous Cell Carcinoma to Boost Immunotherapy Efficacy
Yuying Zhang, Jinbang Li, Xiaoyu Guo, Zhao Gao, Ji‐An Pan, Sheng Nong, Jiyuan Ma, Gang Chen, Jiali Zhang
Abstract
Neoadjuvant immunotherapy is a first-line treatment for recurrent and metastatic head and neck squamous cell carcinoma (HNSCC). However, only a fraction of patients with advanced HNSCC benefit from immunotherapy. Identifying accurate and accessible biomarkers is essential for optimal patient selection. In this study, we integrated single-cell RNA sequencing and T-cell receptor sequencing to comprehensively characterize the tumor immune microenvironment (TIME) of HNSCC biopsies prior to a phase II neoadjuvant immunotherapy clinical trial. Tumor-specific MHC-II (tsMHC-II) was identified as a superior predictor of response to neoadjuvant immunotherapy in HNSCC compared with PD-L1. Mechanistically, tsMHC-II ignited a hot TIME and enhanced the effect of PD-1 blockade by recruiting T cells through the induction of chemokines, particularly CCL5. Moreover, tsMHC-II triggered a Th1 response and activated CD4+ and CD8+ T-cell expansion, suppressing HNSCC growth in a CD4+ T-cell-dependent manner. Simultaneously, tsMHC-II facilitated an increase in PD-1+CD4+ T cells and a modest elevation in tumor PD-L1, thereby enhancing sensitivity to anti-PD-1 therapy. This study highlights that tsMHC-II, by generating an inflamed TIME, is crucial in enhancing the effectiveness of neoadjuvant immunotherapy in HNSCC. SIGNIFICANCE: scRNA-seq analysis identifies tumor-specific MHC-II as a predictor for neoadjuvant immunotherapy response in HNSCC and provides insights into the complex networks that ignite a hot tumor immune microenvironment and regulate T-cell infiltration.