A Mutant Streptokinase Lacking the C-Terminal 42 Amino Acids Is Less Reactive with Preexisting Antibodies in Patient Sera

• Published in: Biochemical and biophysical research communications 1999-12, Vol.266 (1), p.230-236
• Main Authors: Torréns, Isis, Ojalvo, Ariana G., Seralena, Alina, Pupo, Elder, Lugo, Victoria, Páez, Rolando
• Format: Article
• Language: English
• Subjects: Allergens - chemistry; Allergens - immunology; Antibodies, Bacterial - blood; Antibodies, Bacterial - immunology; Antigens, Bacterial - chemistry; Antigens, Bacterial - immunology; Binding, Competitive; Enzyme-Linked Immunosorbent Assay; Escherichia coli; Humans; Immunodominant Epitopes - chemistry; Immunodominant Epitopes - genetics; Immunodominant Epitopes - immunology; Immunodominant Epitopes - isolation & purification; Myocardial Infarction - drug therapy; Myocardial Infarction - immunology; Neutralization Tests; Peptide Fragments - chemical synthesis; Peptide Fragments - chemistry; Peptide Fragments - genetics; Peptide Fragments - immunology; Recombinant Proteins - chemistry; Recombinant Proteins - genetics; Recombinant Proteins - immunology; Recombinant Proteins - isolation & purification; Sequence Deletion - genetics; Streptokinase; Streptokinase - chemistry; Streptokinase - genetics; Streptokinase - immunology; Streptokinase - therapeutic use; Thrombolytic Therapy
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1006/bbrc.1999.1793

Streptokinase (SK) is an efficacious thrombolytic drug for the treatment of myocardial infarction. Because of its immunogenicity, patients receiving SK therapy develop high anti-SK antibody (Ab) titers, which might provoke severe allergic reactions and neutralize SK activity. In this report we studied the reactivity of a synthetic 42-residue peptide resembling SKC-2 C-terminus with patient sera. SKC-2(373–414) peptide was recognized by 39 and 64% of patients, before and after SKC-2 therapy, respectively. An SKC-2 deletion mutant (mut-C42), lacking the same 42 C-terminal residues, was constructed and expressed in Escherichia coli. Recognition of mut-C42 by preexisting Abs from patient sera was 51 and 68% of reactivity to SKC-2, as assessed by direct binding and competition assays, respectively. For most of the patients, mut-C42-neutralizing activity titer (NAT) significantly decreased with respect to SKC-2-NAT. This study opens the possibility of producing a less immunogenic variant of SK, which could constitute a preferred alternative for thrombolytic therapy.