PMEL and neoplasm: As predicted, inhibition of Mgat5 activity in both human and murine T cells resulted in a more potent effector response upon encountering tumor antigen, as evidenced by an increase in IFN-γ production by CD19 CAR-T cells when cocultured with Raji tumor cells (Fig. 7N) and an increase in cytolytic cytokine production by Pmel T cells upon restimulation with gp100 peptide (Fig. 7O).