Viral peptides remodel the tumor immune microenvironment of cold tumors with RNA-seq insights

Cold tumors, characterized by low cytotoxic T cell infiltration, limit immunotherapy efficacy. Current strategies often depend on tumor-specific antigens or non-specific immune activation, restricting translational potential. Here, we present a peptide-based platform that leverages intratumoral expression of influenza-derived peptides to redirect virus-specific CD8⁺ T cells and remodel the tumor immune microenvironment in an antigen-independent manner.

In murine 4T1 and CT26 tumor models, the immunodominant influenza A virus peptide NP_147-155 was delivered via intratumoral peptide injection or stable lentiviral expression. Immune remodeling was assessed using flow cytometry, cytokine profiling, and transcriptomic profiling. Differential gene expression and pathway analyses identified mechanisms underlying cold-to-hot TME conversion.

Intratumoral NP_147-155 expression robustly activated virus-specific CD8⁺ T cells and enhanced IFN-γ secretion. Transcriptomic profiling revealed upregulation of genes associated with cytotoxicity, chemokine signaling, antigen presentation, and the NKG2D-NKG2DL pathway, consistent with increased T cell infiltration and conversion of cold tumors into hot tumors. Tumor growth was significantly suppressed, and durable anti-tumor immunity was established, including in MHC class I-deficient tumors.

This study demonstrates a peptide-based platform to remodel cold tumor immune microenvironments. Integration of transcriptomic profiling provides mechanistic insights and establishes a robust workflow for evaluating immunomodulatory technologies. This tumor-agnostic approach may enhance anti-tumor immunity and improve immunotherapy efficacy in cold tumors.