Antitumor activity of immunotoxins with T-cell receptor-like specificity against human melanoma xenografts.
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.
Klechevsky
Eynav
E
Faculty of Biology, Technion-Israel Institute of Technology, Haifa, Israel and Baylor Institute for Immunology Research, Dallas, Texas.
Gallegos
Michael
M
Denkberg
Galit
G
Palucka
Karolina
K
Banchereau
Jacques
J
Cohen
Cyril
C
Reiter
Yoram
Y
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
D000970:Antineoplastic Agents; D000922:Immunotoxins; D011948:Receptors, Antigen, T-Cell; D011994:Recombinant Proteins