In vitro maintenance and differentiation of bronchioloalveolar progenitors. CD34pos/SP-Cpos/CCSPpos cells from explanted lungs were maintained either in a. “maintenance conditions” with "complete Q286 medium" on fibronectin and collagen-coated inserts, b. differentiated in “AECII conditions” with "complete Q286 medium" on fibronectin and collagen-coated plates or c. in “Club conditions” with "basic Q286 medium" on fibronectin-coated plates. (A) Representative immunostaining from cells isolated from one lamb for SP-C (green) and CCSP (red). Co-expression was performed on in vitro maintained bronchioloalveolar progenitors (SP-Cpos/CCSPpos) or differentiated AECIIs (SP-Cpos/CCSPneg) or club cells (SP-Cneg/CCSPpos). (B) The population of CD34pos/SP-Cpos/CCSPpos cells from a representative lamb grown in maintenance or differentiation media was quantified by flow cytometry for the expression of SP-C or CCSP. The results are presented as dot plots of the expression of both markers. (C) CD34pos/SP-Cpos/CCSPpos cells from 6 independent lambs cultured in maintenance or differentiation media were followed over three passages (p0 to p3) by flow cytometry for the expression of SP-C and CCSP. The results are presented as the mean ± SD of the cells expressing each phenotype.