Eduardo Cruz-Hinojoza

We interrogate antigen-specific CD4 T cells during immunotherapy in pancreatic ductal adenocarcinoma. Vaccination with MHC-II-restricted tumor epitopes impart superior protection compared to an immunodominant MHC-I epitope, prompting development of MHC-II affinity-enhanced tetramers to track tumor-specific CD4 T cells. As tumors progress, tumor-specific CD4 T cells decline, and remaining cells acquire features of regulation. Agonistic anti-CD40 increases Th1 cell clonal expansion and transiently decreases Tregs. Anti-PD-L1 promotes Tfh clonal expansion in draining lymph nodes and tumor while preventing Treg rebound after anti-CD40. Treatment with anti-CD40 promotes intratumoral Stat1 ⁺ macrophages, tertiary lymphoid structures (TLS), and immune triads. MHC-II on myeloid cells but not B cells is required for immunotherapy-induced TLS formation and antitumor effects. IL-15 complex enhances immunotherapy-induced Th1 effectors without promoting Tregs. Human immunotherapy transcriptomics shows conserved Th1 programming and Treg destabilization as a feature of response. Thus, tumor-specific CD4 T cells are central mediators of effective immunotherapy in solid tumors.

Mechanisms driving immunotherapy resistance in pancreatic cancer are poorly defined. We demonstrate that programmed death-ligand 1 immune checkpoint blockade promoted immune evasion by epigenetic Tap1 ( transporter associated with antigen processing 1 ) silencing, increasing selection of metastatic tumor variants with defective interferon-γ (IFN-γ)–inducible class I major histocompatibility complex (MHC-I) expression. Unleashing CD4 conventional T cells by regulatory T cell (T _reg cell) depletion, transfer of tumor-reactive CD4 T cells, or anti–CTLA-4 prevented metastasis. Tumor-specific CD4 T cells adopted a TCF-1 ⁺ SLAMF6 ⁺ progenitor state in lymph nodes and differentiated in tumors. Anti–CTLA-4 increased intratumoral accumulation of CD4 T cells with stemness and tissue residency features, reduced metastasis, and induced gene signatures correlated with improved patient outcomes. MHC-I restoration with anti–CTLA-4 prolonged survival in murine models. In patient tumors, T _reg cells and CD4 T cells colocalized, and abundance correlated with survival. These findings identify targetable mechanisms of immune evasion and metastasis in immunotherapy-resistant cancer.

Antigen specificity and functionality of predominant TCRs from tumors from immunotherapy treated mice.

Single cell transcriptional atlas following anti-PDL1 or agonistic anti-CD40

CD4 T cells and tumor antigen are required for anti-CD40 driven TSTEM accumulation in PDA

Comparison of human and murine tumor-infiltrating CD8 T cells.

IL15C synergizes with immunotherapy to target poorly immunogenic KPC2 tumors

CD8 T cell differentiation in PDA.

IL-15C promotes the activity of dual therapy by promoting T-bet in tumor-infiltrating T cells