Figure S1. MSC-exo decreases repetitive behavior of self-grooming. Intra-subject comparison shows BTBR MSC-exo group spent significantly less time in repetitive behaviors, while BTBR saline and C57BL saline showed no difference between basal and post treatment behavior (paired T test). Inter-group comparison shows BTBR MSC-exo is significantly different than BTBR saline group in time spent in repetitive behaviors. (ANOVA1, Bonferroni). Data is presented as mean + SEM. **p 0.05). B. C57BL MSC-exo mice presented no difference in their number of USV compared to saline-treated group (unpaired T test, p > 0.05). Data is presented as mean + SEM. Figure S3. MSC-exo but not NSC-exo significantly ameliorates male to male social interaction, repetitive behaviors, and male to female ultrasonic vocalizations of BTBR mice. A. male to male social interaction. B. repetitive behaviors. C. male to female ultrasonic vocalizations (ANOVA 1, Bonfferoni *p