Higher cytotoxicity of divalent antibody-toxins than monovalent antibody-toxins.
Recombinant antibody-toxins are constructed via the fusion of a "carcinoma-specific" antibody fragment to a toxin. Due to the high affinity and high selectivity of the antibody fragments, antibody-toxins can bind to surface antigens on cancer cells and kill them without harming normal cells [L.H. Pai, J.K. Batra, D.J. FitzGerald, M.C. Willingham, I. Pastan, Anti-tumor activities of immunotoxins made of monoclonal antibody B3 and various forms of Pseudomonas exotoxin, Proc. Natl. Acad. Sci. USA 88 (1991) 3358-3362]. In this study, we constructed the antibody-toxin, Fab-SWn-PE38, with SWn (n=3, 6, 9) sequences containing n-time repeated (G(4)S) between the Fab fragment and PE38 (38 kDa truncated form of Pseudomonas exotoxin A). The SWn sequence also harbored one cysteine residue that could form a disulfide bridge between two Fab-SWn-PE38 monomers. We assessed the cytotoxicity of the monovalent (Fab-SWn-PE38), and divalent ([Fab-SWn-PE38](2)) antibody-toxins. The cytotoxicity of the dimer against the CRL1739 cell line was approximately 18.8-fold higher than that of the monomer on the ng/ml scale, which was approximately 37.6-fold higher on the pM scale. These results strongly indicate that divalency provides higher cytotoxicity for an antibody-toxin.
Won
JaeSeon
J
College of Life Sciences and Graduate School of Biotechnology, Korea University, 5-ga Anam-dong, Sungbuk-gu, Seoul 136-701, Republic of Korea.
Nam
PilWon
P
Lee
YongChan
Y
Choe
MuHyeon
M
D036002:ADP Ribose Transferases / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D018033:Antibodies, Bispecific / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D000951:Antigens, Neoplasm / Q000276:immunology; D001427:Bacterial Toxins / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D045744:Cell Line, Tumor; D003601:Cytotoxicity Tests, Immunologic; D003602:Cytotoxicity, Immunologic; D005098:Exotoxins / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D006801:Humans; D000922:Immunotoxins / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D017510:Protein Folding; D055503:Protein Multimerization; D037521:Virulence Factors / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D000097668:Pseudomonas aeruginosa Exotoxin A
D036002:ADP Ribose Transferases; D018033:Antibodies, Bispecific; D000951:Antigens, Neoplasm; D001427:Bacterial Toxins; D005098:Exotoxins; D000922:Immunotoxins; D037521:Virulence Factors; D000097668:Pseudomonas aeruginosa Exotoxin A