Modifying an immunogenic epitope on a therapeutic protein: a step towards an improved system for antibody-directed enzyme prodrug therapy (ADEPT)
| Autor: | Nigel P. Minton, Des Purdy, Surinder K. Sharma, Richard H. J. Begent, Peter Amlot, G Tharakan, Berend Tolner, A Mayer, KA Chester |
|---|---|
| Rok vydání: | 2004 |
| Předmět: |
Cancer Research
Immunoconjugates Recombinant Fusion Proteins Enzyme-Linked Immunosorbent Assay Biology immunogenicity Protein Engineering Epitope Epitopes Mice Glutamate carboxypeptidase Carboxypeptidase-G2 Animals Humans Prodrugs Experimental Therapeutics Immunoglobulin Fragments carboxypeptidase G2 Vaccines Synthetic Immunogenicity Antibodies Monoclonal Adept gamma-Glutamyl Hydrolase antibody response Molecular biology Oncology Polyclonal antibodies Antibody Formation biology.protein Antibody Conformational epitope ADEPT |
| Zdroj: | British Journal of Cancer Europe PubMed Central |
| ISSN: | 0007-0920 |
| Popis: | Carboxypeptidase G2 (CP) is a bacterial enzyme, which is targeted to tumours by an antitumour antibody for local prodrug activation in antibody-directed enzyme prodrug therapy (ADEPT). Repeated cycles of ADEPT are desirable but are hampered by human antibody response to CP (HACA). To address this, we aimed to identify and modify clinically important immunogenic sites on MFECP, a recombinant fusion protein of CP with MFE-23, a single chain Fv (scFv) antibody. A discontinuous conformational epitope at the C-terminus of the CP previously identified by the CM79 scFv antibody (CM79-identified epitope) was chosen for study. Modification of MFECP was achieved by mutations of the CM79-identified epitope or by addition of a hexahistidine tag (His-tag) to the C-terminus of MFECP, which forms part of the epitope. Murine immunisation experiments with modified MFECP showed no significant antibody response to the CM79-identified epitope compared to A5CP, an unmodified version of CP chemically conjugated to an F(ab)(2) antibody. Success of modification was also demonstrated in humans because patients treated with His-tagged MFECP had a significantly reduced antibody response to the CM79-identified epitope, compared to patients given A5CP. Moreover, the polyclonal antibody response to CP was delayed in both mice and patients given modified MFECP. This increases the prospect of repeated treatment with ADEPT for effective cancer treatment. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|