Adenosine deaminase activity of ADA2 variants in the homozygous or heterozygous state. (A) Adenosine deaminase activity in the whole-cell lysate of HEK293T cells transfected with WT and ADA2 variants in homozygous conditions. Bar graphs represent the percentage of enzymatic activity relative to WT100% ADA2. (B) Adenosine deaminase activity in the supernatant of HEK293T cells transfected with WT and ADA2 variants in homozygous conditions. Bar graphs represent the percentage of enzymatic activity relative to WT100% ADA2. (C) Adenosine deaminase activity in the whole-cell lysate of HEK293T cells transfected with WT and/or ADA2 variants in heterozygous conditions. Bar graphs represent the percentage of enzymatic activity relative to WT50% ADA2. (D) Adenosine deaminase activity in the supernatant of HEK293T cells transfected with WT and/or ADA2 variants. Bar graphs represent the percentage of enzymatic activity relative to WT50% ADA2. (A–D) Data represent the mean ± SD from three independent experiments. EV, empty vector; DN, dominant negative effect.