SCFV AGAINST EGFRvIII WITH IMPROVED CYTOTOXICITY AND YIELD, IMMUNOTOXINS BASED ON THEREOF AND METHODS FOR THEIR USING Russian patent published in 2008 - IPC C07K16/28 C12P21/00 C12N15/13 A61K39/395 A61P35/00 

FIELD: biotechnology, proteins, immunology.

SUBSTANCE: invention proposes fragment of antibody MR1-1 that retains capacity for recognition and binding EGFRvIII and nucleic acid encoding its. Polypeptide is prepared from the known antibody MR1 by mutation of CDR3 V_H- and V_L-chains. Also, invention describes using a polypeptide for preparing immunotoxin possessing the cytotoxicity property to cells carrying antigen of epidermal growth factor EGFRvIII receptors. Also, invention disclosed immunotoxin based on this polypeptide. Also, invention proposes a method for preparing polypeptide comprising amino acid substitution of at least one amino acid in hypervariable region CDR with amino acid encoded by a codon comprising nucleotide belonging to a hot point motif. The hot point motif is chosen from AGY or RGYW wherein R represents A or G; Y represents C or T, and W represents A or T. Prepared polypeptide is characterized by value K_d for EGFRvIII 7 nM or less. Also, invention describes a method for cell killing that expresses antigen EGFRvIII using a polypeptide. Using this invention provides preparing antibodies showing enhanced cytotoxicity and improved binding EGFRvIII as compared with the parent antibody MR1 that can be used for target-directed delivery of immunotoxins in treatment of malignant neoplasms.

EFFECT: valuable medicinal properties of polypeptide.

34 cl, 7 tbl, 6 dwg, 8 ex