Figure 3. Treg expansion performed in the absence of serum results in more durable Treg suppressive activity.

A. Enriched Tregs were expanded in the absence of human serum. Where indicated, 10 nM ATRA or 100 ng/ml RAPA were added to the medium and this concentration of drug was added to media used to feed the cultures. Cell counting was performed on the indicated days. The data reflects the average of 3 cultures using enriched Tregs from different healthy donors. Error bars represent the standard deviation. (B.) At the end of culture, FOXP3 expression was measured by flow cytometry, and (C.) an in vitro suppressive assay was performed. For parts B. and C., each symbol refers to data collected from a single donor.