Factors related to cystic fibrosis. pp. 277-84.

A variety of bioassays have identified molecules circulating in cystic fibrosis genotypes 
and synthesized in vitro by cultured cells from these genotypes by 
functional disturbances observed in the assays employed. Preliminary characterizations of these 
factors are in general agreement and the properties include a small 
molecular weight polypeptide within the range of 4000 to 10000 MW, 
a heat-labile protein having a cationic charge, and a protein present 
in saliva, serum, urine (and perhaps sweat) which is synthesized in 
vitro by fibroblasts, short-term lymphocytes and long-term lymphoid lines. The relationship 
of the factor or factors to the pathogenesis of cystic fibrosis 
is presently unknown, but its presence in cystic fibrosis genotypes appears 
to be related to the basic defect. 