Competition for trypsin binding between alpha 2-macroglobulin and antitrypsin antibodies in cystic fibrosis.
As previously reported, Tblg, especially TblgG, have been identified in CF patients, and their production appears to be elicited by the porcine trypsin ingested daily by most CF patients. We have measured by IP assay the binding of 125I-trypsin to a alpha 2M and TblgG in plasma of CF patients and controls. Our results do not confirm previous reports of decreased trypsin binding to alpha 2M in whole CF plasma with respect to controls. We have shown, however, that antitrypsin antibodies from CF patients or from rabbits immunized against trypsin compete with alpha 2M for binding with trypsin. This competition can cause apparent decrease of trypsin binding to alpha 2M in vitro.