222. HSV Amplicon Expression of Single Chain Antibodies Directed Against α-Synuclein Conformers

Abstract

Parkinson's disease (PD) is a progressive neurodegenerative disorder which targets the nigrostriatal system and is triggered by disparate mechanisms. The hallmark pathobiologic feature of PD is the formation of intracytoplasmic inclusions known as Lewy bodies. Lewy bodies are composed of aggregated proteins, most notably α-synuclein. The selective insult to the dopamine (DA) neuron is posited to involve oxidative injury mediated in part through participation of DA adducts made onto α-synuclein (α-syn). Oxidative stress and DA-derived orthoquinone adducts form onto α-syn promoting the formation of misfolded protein. We hypothesize that therapies specifically designed to interact and reduce toxic α-syn conformers will attenuate disease progression. We are pursuing a gene therapy approach whereby conformation-specific humanized single-chain Fvs (scFvs) are expressed and intended to interfere with misfolded α-syn. Utilizing various conformers of purified α-syn to screen a combinatorial phage display library expressing human immunoglobulin heavy and light chain variable regions we have identified conformation-specific α-syn-specific scFvs. These scFvs have been efficiently expressed in mammalian cells following transduction with an HSV amplicon vector (HSVscFvs). The effect of transduction and expression of intracellular scFvs, termed intrabodies, within stable cell lines overexpressing α-syn is under investigation. HSVscFvs directed against α-syn afford us the opportunity to further investigate the role of α-syn aggregation in the pathogenesis of PD.