title: Synthesis and immune response of non-native isomers of vascular endothelial growth factor.
abstract: Native proteins often lack immunogenicity and thus limit vaccine and mAb development. We described here a unique method to enhance the immunogenicity of native proteins. This is achieved by creating non-native isomers of disulfide proteins (X-isomers) using the method of disulfide scrambling. X-isomers have the potential to be developed as vaccines and effective immunogens, as they are capable of breaking the immune tolerance and eliciting antibodies that cross-react with the native protein. In this report, we describe production of X-isomers of vascular endothelial growth factor (X-VEGF). The aim is to develop X-VEGF for cancer immunotherapy targeting reduction of VEGF. The production of mouse X-VEGF is achieved by expressing the short version of VEGF (1-110) commonly shared by all VEGF isoforms, with two Cys --> Ala mutations at Cys(51) and Cys(60) to generate R-VEGF(110) (R stands for fully reduced). R-VEGF(110) was then allowed to undergo oxidative folding in the absence of denaturant to form N-VEGF(110) (N stands for native) or in the presence of denaturant to generate five fractions of X-VEGF(110) isomers. While N-VEGF(110) exhibits only marginal immunogenicity in mice, all five fractions of X-VEGF(110) isomers were shown to elicit high titers of antibodies that cross-react with N-VEGF(110). In sera of immunized mice, the amounts of anti-N-VEGF antibodies elicited by X-VEGF(110) isomers range from 54 to 186 mug/mL, which are compatible with or greater than the concentration required for effective therapy using anti-VEGF MAbs. The underlying mechanism of enhanced immunogenicity of X-VEGF(110) is investigated and elaborated. These data suggest that X-VEGF(110) isomers are potential compounds in developing active immunotherapy for treatment of VEGFR bearing tumors and the wet form of age-related macular degeneration.
authors.affiliation: Research Center for Protein Chemistry, Brown Foundation Institute of Molecular Medicine, and Department of Biochemistry and Molecular Biology, The University of Texas, Houston, Texas 77030, USA.
authors.forename: Chuantao
authors.initials: C
authors.lastname: Jiang
authors.forename: Wei
authors.initials: W
authors.lastname: Xiong
authors.forename: Bao-Yuan
authors.initials: BY
authors.lastname: Lu
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Gonda
authors.forename: Jui-Yoa
authors.initials: JY
authors.lastname: Chang
mesh_terms: D000818:Animals; D000917:Antibody Formation / Q000187:drug effects*; D019496:Cancer Vaccines; D007167:Immunotherapy; D008268:Macular Degeneration / Q000628:therapy*; D051379:Mice; D009369:Neoplasms / Q000628:therapy*; D015202:Protein Engineering / Q000379:methods*; D020033:Protein Isoforms / Q000138:chemical synthesis / Q000276:immunology / Q000627:therapeutic use; D042461:Vascular Endothelial Growth Factor A / Q000276:immunology* / Q000627:therapeutic use
chemical_list: D019496:Cancer Vaccines; D020033:Protein Isoforms; D042461:Vascular Endothelial Growth Factor A