The biologic activities of cystic fibrosis serum. II. Ultrastructural aspects of the effect of cystic fibrosis sera and calcium ionophore A23187 on rabbit tracheal explants.

Ultrastructural and cytochemical observations indicate that both cystic fibrosis (CF) sera and 
calcium ionophore A23187 induce a swelling or an increase in the 
size and possibly the number of secondary lysosomes and an increase 
in mucus secretion in epithelium of the rabbit tracheal bioassay system. 
Extended incubation of the rabbit tracheal explants with either CF or 
control sera produces a cytotoxic effect on the tracheal epithelium, but 
only after the termination of the normal bioassay time period. Comparative 
ultrastructural study of the effect of both CF sera and calcium 
ionophore A23187 on the rabbit tracheal bioassay system indicates that increased 
membrane permeability to calcium may be important in the production of 
the ciliary dyskinesia response by CF serum factor(s) in the rabbit 
tracheal bioassay system. 