title: Antitumor activity of immunotoxins with T-cell receptor-like specificity against human melanoma xenografts.
abstract: In this study, we have explored the use of Fab-toxin proteins (immunotoxin) to target antigen-specific MHC-peptide complexes of in vitro and in vivo cancer cells. A human phage display library was used to screen for T-cell receptor (TCR)-like antibodies that are highly specific for the peptide melanoma-associated antigen MART-1(26-35) presented by HLA-A201. We also used previously selected TCR-like antibodies specific for the peptide melanoma-associated antigen gp100(280-288) presented by HLA-A201. The recombinant immunotoxin constructs were generated by fusing the targeting Fab fragment to a truncated form of Pseudomonas exotoxin, PE38KDEL. These immunotoxins bound with high affinity to the EBV-transformed JY cell line pulsed with the aforementioned peptides and internalized within 30 min. A significant inhibition of protein synthesis, which resulted in cell death, was detected at 24 h. MART-1-specific and gp100-specific immunotoxins bound and killed HLA-A201 melanoma MART-1(+) and gp100(+) cell lines that were presented at natural levels but do not bind to HLA-A201(-) or to HLA-A201(+) MART-1(-) and gp100(-) cell lines. In severe combined immunodeficient mice, MART-1 and gp100 immunotoxins significantly and discriminately inhibited human melanoma growth. These results show that MHC class I/peptide complexes can serve as a specific target for passive immunotherapy of cancer.
authors.affiliation: Faculty of Biology, Technion-Israel Institute of Technology, Haifa, Israel and Baylor Institute for Immunology Research, Dallas, Texas.
authors.forename: Eynav
authors.initials: E
authors.lastname: Klechevsky
authors.forename: Michael
authors.initials: M
authors.lastname: Gallegos
authors.forename: Galit
authors.initials: G
authors.lastname: Denkberg
authors.forename: Karolina
authors.initials: K
authors.lastname: Palucka
authors.forename: Jacques
authors.initials: J
authors.lastname: Banchereau
authors.forename: Cyril
authors.initials: C
authors.lastname: Cohen
authors.forename: Yoram
authors.initials: Y
authors.lastname: Reiter
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D000922:Immunotoxins / Q000494:pharmacology*; D008545:Melanoma / Q000276:immunology*; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D011948:Receptors, Antigen, T-Cell / Q000276:immunology*; D011994:Recombinant Proteins / Q000276:immunology; D014183:Transplantation, Heterologous
chemical_list: D000970:Antineoplastic Agents; D000922:Immunotoxins; D011948:Receptors, Antigen, T-Cell; D011994:Recombinant Proteins