Cystic fibrosis: growth kinetics and production of the ciliary inhibitor by cultured fibroblasts

Fractions of media from cultured fibroblasts derived from cystic fibrosis patients and heterozygous parents have been shown to inhibit oyster gill cilia. The media fraction containing the ciliary inhibitor has the properties of a cationic protein. This report describes the growth kinetics of fibroblasts derived from a homozygous cystic fibrosis patient. The relative quantitation of the ciliary inhibitory fraction was determined by end point dilution. The concentration of ciliary inhibitor increased linearly with increasing cell number. The inhibitor is produced in both dividing and nondividing (plateau phase) cells. Karyotypes of cells from the plateau phase indicate that the cells still carry a normal diploid chromosome complement.