CD4 and neoplasm: This study provides evidence for the potential of GS-4774 to be used as a HBV- therapeutic vaccine based on 3 lines of evidence: 1) the induction of HBV Ag-specific CD4+ and CD8+ T cells and anti-tumor responses in multiple mouse models; 2) the activation of T cells that recognize epitopes of known importance in clearance of acute infection, and; 3) the ability to elicit HBV Ag-specific T cell responses ex vivo in both healthy and chronically-infected human donor cells.