Immune effects of optimized DNA vaccine and protective effects in a MPTP model of Parkinson's disease

It has been suggested that DNA vaccine plays a protective effect on degenerative diseases in the central nervous system (CNS), the Parkinson's disease (PD) included. In this study, we assessed the immune effects of optimized DNA vaccine (pVAX1-IL-4/SYN-B) in the C57BL/6 mice by ELISA, and immunohistochemistry. We also evaluated the neuroprotective effect of pVAX1-IL-4/SYN-B in MPTP model of Parkinson's disease, using behavioral methods, immunohistochemistry and western blot. We found that alphα-synuclein (α-syn) antibody significantly increased, IL-4 increased and IFN-r reduced in the serum of immunized C57BL/6 mice in optimized DNA vaccine group. The immune serum of mice specifically combined with the α-syn positive inclusion bodies in the brain of PD model mice. The preventive immunization with optimized DNA vaccine made the motor symptoms improved significantly, the apoptosis of tyrosine hydroxylase (TH) neuron and cyclooxygenase-2 (COX-2) expression significantly decreased in MPTP model mice. These results suggest that optimized DNA vaccine can make immunized mice produce high titers of specific α-syn antibody, mainly causing the humoral immune response; preventive immunization with optimized DNA vaccine can play neuroprotective and anti-inflammatory effects on mice suffering from the sub-acute MPTP Parkinson's disease.