Electrophoretic studies of the cystic fibrosis ciliary inhibitor and its interaction with immunoglobulin G.

The cystic fibrosis ciliary inhibitor (CFCI) has been partially purified from serum 
and plasma of cystic fibrosis (CF) homozygotes and heterozygotes, and from 
media of cultured fibroblasts derived from cystic fibrosis genotypes. Characterization and 
comparison of fractions containing the CFCI were carried out by polyacrylamide 
gel electrophoresis. Gel electrophoresis confirmed previous molecular weight estimations of 4,500 
to 11,000 for the CFCI and provided an estimate of the 
number of proteins present in the fractions. Low molecular weight proteins 
from serum and media were combined with IgG preparations. No specific 
binding to IgG by the media fraction containing the CFCI could 
be demonstrated by the techniques employed. There was decreased binding of 
the low molecular weight serum fraction containing CFCI to native IgG 
molecules from cystic fibrosis patients as compared to IgG from normal 
individuals. However, IgG from CF individuals demonstrated increased binding of the 
cfci- containing low molecular weight serum fraction after gel filtration in 
the presence of guanidinium chloride. This suggests: 1) that very low 
concentrations of CFCI are present in media fractions; and 2) that 
native CF IgG cannot bind the low molecular weight CFCI fractions 
to the same degree as native IgG from normals or CF 
IgG that has been dissociated from non-covalently bound components. 