Deciphering the interplay of HPV infection, MHC-II expression, and CXCL13+ CD4+ T cell activation in oropharyngeal cancer: implications for immunotherapy.

Background: Human papillomavirus (HPV) infection has become an important etiological driver of oropharyngeal squamous cell carcinoma (OPSCC), leading to unique tumor characteristics. However, the interplay between HPV-associated tumor cells and tumor microenvironment (TME) remains an enigma.

Methods: We performed a single-cell RNA-sequencing (scRNA-seq) on HPV-positive (HPV⁺) and HPV-negative (HPV^‒) OPSCC tumors, each for three samples, and one normal tonsil tissue. Ex vivo validation assays including immunofluorescence staining, cell line co-culture, and flow cytometry analysis were used to test specific subtypes of HPV⁺ tumor cells and their communications with T cells.

Results: Through a comprehensive single-cell transcriptome analysis, we uncover the distinct transcriptional signatures between HPV⁺ and HPV^‒ OPSCC. Specifically, HPV⁺ OPSCC tumor cells manifest an enhanced interferon response and elevated expression of the major histocompatibility complex II (MHC-II), potentially bolstering tumor recognition and immune response. Furthermore, we identify a CXCL13⁺CD4⁺ T cell subset that exhibits dual features of both follicular and pro-inflammatory helper T cells. Noteworthily, HPV⁺ OPSCC tumor cells embrace extensive intercellular communications with CXCL13⁺CD4⁺ T cells. Interaction with HPV⁺ OPSCC tumor cells amplifies CXCL13 and IFNγ release in CD4⁺T cells, fostering a pro-inflammatory TME. Additionally, HPV⁺ tumor cells expressing high MHC-II and CXCL13⁺CD4⁺ T cell prevalence are indicative of favorable overall survival rates in OPSCC patients.

Conclusions: Together, our study underscores a synergistic inflammatory immune response orchestrated by highly immunogenic tumor cells and CXCL13⁺CD4⁺ T cells in HPV⁺ OPSCC, offering useful insights into strategy development for patient stratification and effective immunotherapy in OPSCC.