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Infection with a recombinant vaccinia virus encoding myelin proteolipid protein causes suppression of chronic
L Y Wang1, D J Theil, J L Whitton
1Department of Neurology, University of Utah School of Medicine, Salt Lake City 84132, USA.
Abstract:
Mice infected with a recombinant vaccinia virus (VVplp) encoding the myelin proteolipid protein (PLP) and then challenged with the encephalitogenic peptide, PLP139-151, developed a more severe acute attack vs. control mice. Following this initial acute attack, vaccinated mice had significantly less clinical disease (relapses) than control vaccinated or mock vaccinated mice. Control mice developed a relapsing-remitting disease with severe clinical relapses. During the remission state in VVplp vaccinated mice, histopathologic changes were markedly reduced in the central nervous system (CNS) vs. control vaccinated or unvaccinated mice. Inflammation was mainly limited to the meninges with a reduction of mononuclear cells in the parenchyma of the spinal cord in VVplp vaccinated and PLP139-151 challenged mice vs. control mice where inflammatory changes with demyelination was observed. During the remission period an increase in IL-4 was seen. In addition, there was significantly less T cell proliferation to PLP139-151 that was confirmed by an in vivo measurement of T cell reactivity, DTH responses. This suggests that the almost permanent remission state was dictated by a decreased responsiveness to PLP139-151 in VVplp vaccinated mice.
Insights
Mice vaccinated with a recombinant vaccinia virus encoding myelin proteolipid protein (PLP) experienced a severe initial attack but then achieved long-term remission from autoimmune disease, unlike control groups.
Area of Science:
- Neuroimmunology
- Vaccinology
- Autoimmune Disease Research
Background:
- Multiple Sclerosis (MS) is a chronic autoimmune disease targeting the central nervous system (CNS).
- Myelin proteolipid protein (PLP) is a key autoantigen implicated in MS pathogenesis.
- Developing effective therapeutic strategies for MS remains a significant challenge.
Purpose of the Study:
- To investigate the efficacy of a recombinant vaccinia virus encoding PLP (VVplp) in a mouse model of experimental autoimmune encephalomyelitis (EAE).
- To evaluate the impact of VVplp vaccination on disease severity, clinical relapses, and CNS pathology.
- To explore the underlying immunological mechanisms, including T cell responses and cytokine profiles, associated with VVplp vaccination.
Main Methods:
- Induction of EAE in mice using the encephalitogenic PLP139-151 peptide.
- Vaccination of mice with VVplp, control vaccinia virus, or mock vaccine.
- Clinical scoring of disease severity and relapses.
- Histopathological analysis of CNS tissue for inflammation and demyelination.
- Assessment of T cell proliferation and delayed-type hypersensitivity (DTH) responses in vitro and in vivo.
- Measurement of IL-4 levels during remission.
Main Results:
- VVplp-vaccinated mice exhibited a more severe acute EAE attack but significantly reduced relapses and overall disease burden compared to controls.
- Histopathology revealed markedly reduced CNS inflammation and demyelination in VVplp-vaccinated mice during remission, with inflammation primarily confined to the meninges.
- VVplp vaccination led to decreased T cell proliferation and DTH responses to PLP139-151, correlating with sustained remission.
- Elevated IL-4 levels were observed during the remission phase in VVplp-vaccinated mice.
Conclusions:
- VVplp vaccination can induce a state of long-term remission in a PLP-induced EAE model.
- This remission is associated with reduced T cell responsiveness to the encephalitogenic PLP peptide.
- The findings suggest a potential therapeutic strategy for MS by modulating T cell reactivity through viral vector-based vaccination.