Absence of an alpha two-macroglobulin-protease complex in cystic fibrosis.

The present study using immunologic methodology confirms previous observations from this laboratory 
of an absence of a protease component with arginine esterase activity 
in plasma of patients with cystic fibrosis. In this study, the 
pooled plasma from control individuals was activated and partially purified after 
adsorption on columns of soybean trypsin inhibitor conjugated to Sepharose 4B 
followed by elution with benzamidine. The fraction was further purified by 
isoelectrofocusing on polyacrylamide gels. Proteins around the pI range of 5.5 
were eluted and utilized to prepare an antiserum. Immunoelectrophoresis of activated 
plasma samples from control subjects and patients with cystic fibrosis was 
performed utilizing the antiserum. In controls, four precipitin arcs with residual 
esterase activity were observed, whereas only three were seen in plasma 
from patients with cystic fibrosis. Double gel diffusion experiments using specific 
antisera ruled out the presence of trypsin, chymotrypsin, plasminogen, prothrombin, C1 
esterase, alpha one-trypsin inhibitor, and inter-alpha-trypsin inhibitor in the concentrated benzamidine 
eluate. The antisera to alpha two- macroglobulin gave an immunoprecipitate which 
was readily stained for proteolytic activity. On immunoelectrophoresis, the alpha two- 
macroglobulin precipitin band corresponded to the band absent in plasma of 
patients with cystic fibrosis. In contrast, the alpha two- macroglobulin levels 
were similar in plasma of control subjects and patients with cystic 
fibrosis. Using the antiserum to the protein fractith proteolytic activity could 
be demonstrated in control plasma. One specific enzyme-active "rocket" was absent 
in plasma of patients with cystic fibrosis. In a double blind 
study of 15 control samples and 15 samples from patients with 
cystic fibrosis, a specific "rocket" was shown to be present in 
13 control samples and absent in 14 cystic fibrosis samples. alpha 
two-Macroglobulin was determined by both an immunologic procedure and by its 
trypsin binding (trypsin protein esterase concentration). The ratio of the immunologic 
assay to the biologic activity assay was 90 for the normal 
plasma samples and only 65 for cystic fibrosis samples. 