Notch inhibition decreases autoantibody production. MRL-lpr mice were randomized to treatment with DAPT or vehicle (4 treated, 4 control). Retro-orbital bleeds were obtained every 2 weeks to measure mouse total IgG (anti-IgG2a) and mouse anti-dsDNA IgG specific antibodies in sera by quantitative ELISA. Mice treated with DAPT had a statistically significant decrease in average titer levels compared with control for both antibodies (P < .001) as determined by ANOVA. Error bars represent SD.