In dish (Figure 3C and Supplementary Figure S9A for monoculture, Supplementary Figure S10A for co-culture), IL-2 increases over time and with increasing values of CAR T-cell dose, CD4+:CD8+ ratio, CAR affinity, and cancer antigen expression level due to increased numbers of activated CD4+ CAR T-cells. The gene discussed is CD8A; the disease is cancer.