Sublingual immunization with Japanese encephalitis virus vaccine effectively induces immunity through both cellular and humoral immune responses in mice

The Japanese encephalitis virus (JEV) is the leading cause of viral encephalitis. Although there are four classes of vaccines against JEV, all of them are administered by s.c or i.m injection. Here, the effectiveness of sublingual (s.l.) administration of a JEV live‐attenuated vaccine or recombinant modified vaccinia virus Ankara (MVA) vaccine, including JEV prM/E, was investigated. The mice were immunized three times i.m. or s.c. One week after the final immunization by both s.l. and i.m. routes, the titers of IgG1 induced by the recombinant MVA vaccine were higher than those induced by the live‐attenuated vaccine, whereas the titers of IgG2a induced by the live‐attenuated vaccine were higher than those induced by the recombinant MVA vaccine. However, both vaccines induced neutralizing antibodies when given by either s.l. or i.m. routes, indicating that both vaccines induce appropriate Th1 and Th2 cell responses through the s.l. and i.m. routes. Moreover, both vaccines protected against induction of proinflammatory cytokines and focal spleen white pulp hyperplasia after viral challenge. Virus‐specific IFN‐γ⁺ CD4⁺ and CD8⁺ T cells appeared to increase in mice immunized via both s.l. and i.m. routes. Interestingly, virus‐specific IL‐17⁺ CD4⁺ T cells increased significantly only in the mice immunized via the s.l. route; however, the increased IL‐17 did not affect pathogenicity after viral challenge. These results suggest that s.l. immunization may be as useful as i.m. injection for induction of protective immune responses against JEV by both live‐attenuated and recombinant MVA vaccines.     

The role of the acidic domain of α-synuclein in amyloid fibril formation: a molecular dynamics study

The detailed mechanism of the pathology of α-synuclein in the Parkinson’s disease has not been clearly elucidated. Recent studies suggested a possible chaperone-like role of the acidic C-terminal region of α-synuclein in the formation of amyloid fibrils. It was also previously demonstrated that the α-synuclein amyloid fibril formation is accelerated by mutations of proline residues to alanine in the acidic region. We performed replica exchange molecular dynamics simulations of the acidic and nonamyloid component (NAC) domains of the wild type and proline-to-alanine mutants of α-synuclein under various conditions. Our results showed that structural changes induced by a change in pH or an introduction of mutations lead to a reduction in mutual contacts between the NAC and acidic regions. Our data suggest that the highly charged acidic region of α-synuclein may act as an intramolecular chaperone by protecting the hydrophobic domain from aggregation. Understanding the function of such chaperone-like parts of fibril-forming proteins may provide novel insights into the mechanism of amyloid formation.     

Clinical relevance of infections with zoonotic and human oral species of <Emphasis Type="Italic">Campylobacter</Emphasis>

Genus Campylobacter has been recognized as a causative bacterial agent of animal and human diseases. Human Campylobacter infections have caused more concern. Campylobacters can be classified into two groups in terms of their original host: zoonotic and human oral species. The major zoonotic species are Campylobacter jejuni and Campylobacter coli, which mostly reside in the intestines of avian species and are transmitted to humans via consumption of contaminated poultry products, thus causing human gastroenteritis and other diseases as sequelae. The other campylobacters, human oral species, include C. concisus, C. showae, C. gracilis, C. ureolyticus, C. curvus, and C. rectus. These species are isolated from the oral cavity, natural colonization site, but have potential clinical relevance in the periodontal region to varying extent. Two species, C. jejuni and C. coli, are believed to be mainly associated with intestinal diseases, but recent studies suggested that oral Campylobacter species also play a significant role in intestinal diseases. This review offers an outline of the two Campylobacter groups (zoonotic and human oral), their virulence traits, and the associated illnesses including gastroenteritis.     

<Emphasis Type="Italic">Arcobacter acticola</Emphasis> sp. nov., isolated from seawater on the East Sea in South Korea

A Gram-stain-negative, facultative aerobic, non-flagellated, and rod-shaped bacterium, designated AR-13^T, was isolated from a seawater on the East Sea in South Korea, and subjected to a polyphasic taxonomic study. Strain AR-13^T grew optimally at 30°C, at pH 7.0–8.0 and in the presence of 0–0.5% (w/v) NaCl. The phylogenetic trees based on 16S rRNA gene sequences showed that strain AR-13^T fell within the clade comprising the type strains of Arcobacter species, clustering coherently with the type strain of Arcobacter venerupis. Strain AR-13^T exhibited 16S rRNA gene sequence similarity values of 98.1% to the type strain of A. venerupis and of 93.2–96.9% to the type strains of the other Arcobacter species. Strain AR-13^T contained MK-6 as the only menaquinone and summed feature 3 (C_16:1ω7c and/or C_16:1ω6c), C_16:0, C_18:1ω7c, and summed feature 2 (iso-C_16:1 I and/or C_14:0 3-OH) as the major fatty acids. The major polar lipids detected in strain AR-13^T were phosphatidylethanolamine, phosphatidylglycerol, and one unidentified aminophospholipid. The DNA G+C content was 28.3 mol% and its mean DNA-DNA relatedness value with the type strain of A. venerupis was 21%. Differential phenotypic properties, together with its phylogenetic and genetic distinctiveness, revealed that strain AR-13^T is separated from recognized Arcobacter species. On the basis of the data presented, strain AR-13^T is considered to represent a novel species of the genus Arcobacter, for which the name Arcobacter acticola sp. nov. is proposed. The type strain is AR-13^T (=KCTC 52212^T =NBRC 112272^T).