IL4 and neoplasm: Conversely, treating tumor-bearing mice with IL-4 complexes (IL-4 bound to anti-IL-4 mAb to enhance its in vivo half-life) recapitulated the effect of anti-PD-1 mAb on OT-I CD8+ T cell expansion (Fig. 7, E and F) and TNF-α+IFN-γ+ double-producer T cells (Fig. 7 G).