Mapping of the antigenic regions of streptokinase in humans after streptokinase therapy

Streptokinase (SK) is efficaciously used as a thrombolytic drug for the tre atment of myocardial infarction. Being a bacterial protein, SK is immunogen ic in humans. Therefore, resulting from SK therapy, patients become immuniz ed and anti-SK antibody (Ab) titers rise post-treatment. High Ab titers mig ht provoke severe immune reactions during SK therapy and neutralize SK acti vity, preventing effective thrombolysis. Spot synthesis combined with pepti de library techniques is a useful tool for studying protein-peptide interac tions on continuous cellulose membranes. Here, we report on the mapping of antigenic regions of SK using a spot-synthesized peptide library and human total sera from patients receiving SK therapy. All tested samples have high anti-SK Ab titers and most of them show significant SK neutralizing capaci ty. Individual variations in peptide recognition were detected. However, pa tients treated with SK tend, in general, to show a common regional binding pattern, including residues 1-20, 130-149, 170-189, and 390-399. This is th e first study reporting the probing of a cellulose-bound set of peptides wi th total human sera. (C) 1999 Academic Press.