Denileukin diftitox, a recombinant fusion protein of diphtheria toxin active domain and IL-2, induced diphtheria toxin to kill CD25 cells expressing the high-affinity IL-2 receptor through the binding of IL-2 moiety, to reduce the frequency of Treg and myeloid-derived suppressor cells (MDSCs, CD11b+GR1HI) frequency, improve pathological damage, reduce the number of viable bacteria, and inhibit the spread of Mtb in a TB mouse model (Gupta et al., 2017). The gene discussed is IL2; the disease is tuberculosis.