Antigen-specific CD4 T cell polarization is altered by immune checkpoint blockade in pancreatic ductal adenocarcinoma

Abstract Pancreatic ductal adenocarcinoma (PDA) is a lethal malignancy with poor response to conventional immune checkpoint inhibitors. Early data by our group suggests CD4 T cell depletion abrogates novel combination therapy that transiently curative in murine model of PDA. Given the importance cells PDA control, we now seek describe dynamics at an antigen-specific resolution. To this end, developed tetramer reagent towards recently identified MHC class II epitope. Through this, observe T-cell polarization distinct from bulk population both spleen and tumor microenvironment. Tumor-specific also displayed differential during therapy, suggesting positive mediated part TCR-dependent stimulation compartment.