Figure 4. Validation of a screening platform to identify CK19+ cell mitogens.

A) Number of CK19+ cells at the end of the culture normalized to the number obtained in basal serum-free medium culture. B) Fraction of CK19+ cells that incorporated BrdU during the last day of culture, normalized to BrdU incorporation in basal medium culture. Unsorted cells were seeded on day 0 while CD90-depleted cells were sorted and seeded on day 1. The data were pooled from cultures ending on day 8 (N = 5 pancreata) or day 6 (N = 3 pancreata) and normalized for each pancreas prior to calculating averages and errors. The non-normalized results obtained at the end of the cultures in basal medium were as follows: the unsorted populations contained 0.05±0.02×10⁵ CK19+ cells/cm² of which 6±3% were BrdU+; the CD90-depleted populations contained 0.07±0.02×10⁵ CK19+ cells/cm² of which 1.0±0.6% were BrdU+. *p<0.05 compared to basal medium.