CD4 and neoplasm: Suggestive of robust priming of tumor antigen-specific T cells underlying these improvements in tumor control enabled by GSNO and aCTLA-4 when used in combination, the populations of CD4+ and CD8+ T cells that express activation markers CD25+ and LAG-3+, as well as antigen-experience marker PD-1+, were increased in the blood, as were tetramer-positive, tumor antigen-specific CD8+ T cells (Fig. 3g, h)29,30.