Daphne E. deMello
Clara cells are believed to be the progenitor of the peripheral airway epithelium and they produce the surfactant proteins SP-A, SP-B and SP-D in addition to the Clara cell secretory protein (CCSP or CC10). A conditionally immortalized mouse lung Clara cell line, designated C22, was derived from the H-2Kb-txA58 transgenic mouse. The promoter is active in a wide range of tissues and is induced by interferons (IFN). From the lungs of mice harboring the hybrid construct Clara cells were isolated and characterized. The Clara cells harboring the hybrid construct (C22 cells) contain secretory granules and mitochondria typical of Clara cells and express the surfactant proteins SP-A, SP-B, SP-D and the Clara cell secretory protein, CC10. Withdrawal from C22 cells of IFN and elevation of the incubation temperature permits cell differentiation similar to that of Clara cells in vivo. (Refer: In Vitro Cell. Dev. Biol - Animal 38:154-164, Mar. 2002).