Fig. 7.

CD26 identifies three CD4⁺ T cell subsets with distinct properties. Depiction of our observations on CD26 expression and cellular therapy described herein. CD26^neg T cells, despite their enhanced capacity to migrate, fail to regress tumors due to regulatory properties, decreased persistence, and increased sensitivity to cell death. CD26^int and CD26^high T cells exhibit similar antitumor activity, but have vastly different immunological properties. Despite their decreased migration, CD26^int T cells are naive and capable of persisting long-term. CD26^high T cells, despite their differentiated phenotype, exhibit several anti-apoptotic and stemness features, persist long-term, co-secrete multiple cytokines, and cytotoxic molecules and have a natural capacity to migrate towards various established solid tumors