Identification, production and use of staphylokinase derivatives with reduced immunogenicity and/or reduced clearance

摘要

Methods for the identification, production and use of staphylokinase derivatives characterized by a reduced immunogenicity after administration in patients and that can be administered by single intravenous bolus injection. The derivatives of the invention are obtained by preparing a DNA fragment comprising at least the part of the coding sequence of staphylokinase that provides for its biological activity; performing in vitro site-directed mutagenesis on the DNA fragment to replace one or more codons for wild-type amino acids by a codon for another amino acid; cloning the mutated DNA fragment in a suitable vector; transforming or transfecting a suitable host cell with the vector; culturing the host cell under conditions suitable for expressing the DNA fragment; purifying the expressed staphylokinase derivative to homogeneity and chemically modifying substituted Cys residues with thiol-directed polyethylene glycol; preferably the DNA fragment is a 453 bp EcoRI-HindIII fragment of the plasmid pMEX602sakB, (pMEX.SakSTAR), the in vitro site-directed mutagenesis is performed by spliced overlap extension polymerase chain reaction and the mutated DNA fragment is expressed in E. coli strain TG1 or WK6. The invention also relates to pharmaceutical compositions comprising at least one of the staphylokinase derivatives according to the invention together with a suitable excipient, for treatment of arterial thrombosis.