A novel PADRE-Kv1.3 vaccine effectively induces therapeutic antibodies and ameliorates experimental autoimmune encephalomyelitis in rats.

Previous studies have confirmed that selective blockade of Kv1.3 channels could modulate the activities of pathogenic T cells and microglia/macrophages, which play key roles in experimental autoimmune encephalomyelitis (EAE). In this study, we designed an anti-Kv1.3 vaccine (PADRE-Kv1.3) to explore its protective role in EAE rat models. When the vaccine was applied in EAE rats, clinical scores and several staining techniques were used to evaluate the severity of the disease. T cell subtypes and related cytokines, as well as microglia/macrophage activation were assayed through flow cytometry, qRT-PCR or immunofluorescence staining, respectively. We herein showed that rats and mice developed high titers of anti-Kv1.3 antibodies and appeared no abnormal manifestations after the PADRE-Kv1.3 vaccine treatment. In EAE models, the vaccine treatment effectively alleviated the clinical severity and lessened pathological damages in the central nervous system (CNS). In addition, we found the vaccine significantly decreased the number of pathogenic T cells (Th17 and IFN-γ-producing T cells) and the production of related pro-inflammatory cytokines (IL-17A, IFN-γ and IL-1β), but increased the number of protective T subsets (CD4+IL-10+ T cells and Treg cells) in the spleen or CNS. Moreover, the infiltration of microglia/macrophages significantly reduced and these cells shifted toward anti-inflammatory M2 subtype in the CNS after the vaccine treatment. Thus, we demonstrated that the PADRE-Kv1.3 vaccine could induce therapeutic anti-Kv1.3 antibodies and ameliorate EAE in rats effectively and safely, which provides a new field of vision for the protection and therapy of multiple sclerosis.