Decreased immune reactivity towards a knobless, affibody-targeted adenovirus type 5 vector

• Published in: Gene therapy Vol. 14; no. 4; pp. 376 - 381
• Main Authors: MYHRE, S, HENNING, P, GRANIO, O, TYLÖ, A. S, NYGREN, P. A, OLOFSSON, S, BOULANGER, P, LINDHOLM, L, HONG, S.-S
• Format: Journal Article
• Language: English
• Published: Basingstoke Nature Publishing Group 01.02.2007
• Subjects: Adenovirus; Adenoviruses; Adenoviruses, Human - genetics; Adenoviruses, Human - immunology; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Antibodies; Antibodies, Viral - blood; Antibodies, Viral - immunology; Antigens, Viral - genetics; Applied cell therapy and gene therapy; Biological and medical sciences; Biotechnology; Blood donors; Blood tests; Capsid Proteins - genetics; determinants; fiber; Fundamental and applied biological sciences. Psychology; gene; Gene Deletion; Gene expression; Gene therapy; Genetic aspects; Genetic Engineering; Genetic Vectors - genetics; Genetic Vectors - immunology; Health aspects; Health. Pharmaceutical industry; hexon; Humans; Immunity; Industrial applications and implications. Economical aspects; knob; libraries; mechanism; Medical sciences; Molecular biology; Neutralization Tests; neutralizing antibodies; penton base; Physiological aspects; Proteins; Prototypes; receptor; recombinant adenovirus; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - immunology; staphylococcal protein-a; Transfusions. Complications. Transfusion reactions. Cell and gene therapy; Viral antibodies; Virology; virus; virus neutralization; Sweden; fiber; Adenoviridae; virus neutralization; knob; Antibody; penton base; neutralizing antibodies; Virus; Adenovirus 5; Human adenovirus; adenovirus; Mastadenovirus; Hexon; Gene therapy; Vector; Neutralization
• ISSN: 0969-7128; 1476-5462; 1476-5462
• DOI: 10.1038/sj.gt.3302875

In this study, a prototype Adenovirus type 5 (Ad5) vector deleted of the fiber knob domain and carrying an Affibody molecule as the targeting ligand showed decreased susceptibility to human pre-existing antibodies. This vector, Ad5/R7-Z(taq)Z(taq), has short fibers carrying seven shaft repeats, a non-native trimerization signal and an affibody molecule (Z(taq)) reactive to Taq polymerase. Ad5/R7-Z(taq)Z(taq) could be specifically targeted to 293 cells stably expressing membrane-bound anti-Z(taq) idiotypic affibody called Z(ztaq) (293Z(ztaq)). Sera from 50 blood donors were analyzed for neutralization activity (NA) against the parental Ad5/Fiwt vector and knobless Ad5/R7-Z(taq)Z(taq) on 293Z(ztaq) cells. Twenty-three sera had NA titers (> or =1:64) against Ad5/Fiwt (46%) and only two against Ad5/R7-Z(taq)Z(taq) (4%). Characterization of sera with NA titers showed that the knob domain is one of the targets of the antibodies. Neutralization assays using sera pre-adsorbed on knob and hexon proteins showed that the NA of the sera was carried mainly by anti-knob and anti-hexon antibodies, but in certain sera the anti-hexon antibodies represent the major population of the neutralizing antibodies (NAbs). Our results suggested that a combination of knob deletion and hexon switching could be an effective strategy for Ad vectors to better evade the anti-Ad NAbs.