Abstract
Purpose: :
Ocular neovascularisation due to uncontrolled growth of new vessels into the retina following overexpression of vascular endothelial growth factor (VEGF) is the main cause of visual impairment in retinal neovascular diseases such as age-related macular degeneration (AMD) or diabetic retinopathy (DR). Intraocular injections of molecules that block the activity of VEGF, like Bevacizumab (Avastin®) or Ranibizumab (Lucentis®), represent the current therapy of choice. However, the short half life of these molecules necessitates repeated injections of the drug into the vitreous, which implies the possibility for negative side effects of the surgical procedure. The purpose of this study was the development of a vector system that allows for the expression of anti-VEGF F(ab) antibody fragments in different eukaryotic cell lines in vitro.
Methods: :
Both antibody chains, the light and part of the heavy chain that constitute the anti-VEGF F(ab) antibody fragment, were designed in frame with a secretory leader sequence and cloned into an expression cassette containing an internal ribosomal entry site (IRES). Expression of the transgenes was placed under the control of a strong viral CMV promoter. The vector plasmid was expressed in several cell lines in vitro, including HEK 293, HeLa, and retinal cell lines arpe19 and Y79.
Results: :
Both chains of the anti-VEGF F(ab) antibody fragment can be produced in eukaryotic cell lines in vitro. Expression of the protein chains was assessed by RT-PCR and Western Blot and the biological function of the heterodimeric antibody fragment was studied by a cell proliferation assay.
Conclusions: :
The results of this study may allow for the development of an alternative treatment strategy for patients with AMD or DR, in which the anti-VEGF F(ab) antibody fragment is expressed directly in retinal cells following vector mediated gene transfer.
Keywords: neovascularization • vascular endothelial growth factor • age-related macular degeneration