Figure 5. Phenotypic shift of the Type B CPC populations.

(A) Our repeated observation was that it was possible to get a ∼95% CD45 and c-kit^pos CPC population by doing a passage 14–17 days after establishing the culture. There was no difference found between using a low enzyme concentration or no enzymes at all. (B) A fast down-regulation of CD45 expression between the 3^rd and 4^th passages. Time between passages was one week. (C) Change of c-kit and CD45 expression in the Type B CPC population over time. Decrease in c-kit expression is observed, followed by a decrease in CD45 expression. (D) Proportions of different subpopulations in the Type B CPC population during different passages. (E) During the spontaneous differentiation c-kit expression is down-regulated first, followed by down-regulation of CD45 expression.