Middle East respiratory syndrome coronavirus (MERS-CoV) has continued spreading since its emergence in 2012 with a mortality rate of 35.6%, and is a potential pandemic threat. Prophylactics and therapies are urgently needed to address this public health problem. We report here the efficacy of a vaccine consisting of chimeric virus-like particles (VLP) expressing the receptor binding domain (RBD) of MERS-CoV. In this study, a fusion of the canine parvovirus (CPV) VP2 structural protein gene with the RBD of MERS-CoV can self-assemble into chimeric, spherical VLP (sVLP). sVLP retained certain parvovirus characteristics, such as the ability to agglutinate pig erythrocytes, and structural morphology similar to CPV virions. Immunization with sVLP induced RBD-specific humoral and cellular immune responses in mice. sVLP-specific antisera from these animals were able to prevent pseudotyped MERS-CoV entry into susceptible cells, with neutralizing antibody titers reaching 1: 320. IFN-γ, IL-4 and IL-2 secreting cells induced by the RBD were detected in the splenocytes of vaccinated mice by ELISpot. Furthermore, mice inoculated with sVLP or an adjuvanted sVLP vaccine elicited T-helper 1 (Th1) and T-helper 2 (Th2) cell-mediated immunity. Our study demonstrates that sVLP displaying the RBD of MERS-CoV are promising prophylactic candidates against MERS-CoV in a potential outbreak situation.

Macroautophagy/autophagy delivers damaged proteins and organelles to lysosomes for degradation, and plays important roles in maintaining tissue homeostasis by reducing tissue damage. The translocation of LC3 to the limiting membrane of the phagophore, the precursor to the autophagosome, during autophagy provides a binding site for autophagy cargoes, and facilitates fusion with lysosomes. An autophagy-related pathway called LC3-associated phagocytosis (LAP) targets LC3 to phagosome and endosome membranes during uptake of bacterial and fungal pathogens, and targets LC3 to swollen endosomes containing particulate material or apoptotic cells. We have investigated the roles played by autophagy and LAP in vivo by exploiting the observation that the WD domain of ATG16L1 is required for LAP, but not autophagy. Mice lacking the linker and WD domains, activate autophagy, but are deficient in LAP. The LAP −/mice survive postnatal starvation, grow at the same rate as littermate controls, and are fertile. The liver, kidney, brain and muscle of these mice maintain levels of autophagy cargoes such as LC3 and SQSTM1/p62 similar to littermate controls, and prevent accumulation of SQSTM1 inclusions and tissue damage associated with loss of autophagy. The results suggest that autophagy maintains tissue homeostasis in mice independently of LC3-associated phagocytosis. Further deletion of glutamate E230 in the coiled-coil domain required for WIPI2 binding produced mice with defective autophagy that survived neonatal starvation. Analysis of brain lysates suggested that interactions between WIPI2 and ATG16L1 were less critical for autophagy in the brain, which may allow a low level of autophagy to overcome neonatal lethality.

Vibrio cholerae causes a severe disease that kills thousands of people annually. The outer membrane protein OmpU is the most abundant outer membrane protein in V. cholerae, and has been identified as an important virulence factor that is involved in host-cell interaction and recognition, as well as being critical for the survival of the pathogenic V. cholerae in the host body and in harsh environments. The mechanism of these processes is not well understood owing to a lack of the structure of V. cholerae OmpU. Here, the crystal structure of the V. cholerae OmpU trimer is reported to a resolution of 2.2 Å . The protomer forms a 16--stranded barrel with a noncanonical N-terminal coil located in the lumen of the barrel that consists of residues Gly32-Ser42 and is observed to participate in forming the second gate in the pore. By mapping the published functional data onto the OmpU structure, the OmpU structure reinforces the notion that the long extracellular loop L4 with a -hairpin-like motif may be critical for host-cell binding and invasion, while L3, L4 and L8 are crucially implicated in phage recognition by V. cholerae.

Chondroitin sulfate (CS) is widely applied in the medical, clinical, and nutraceutical fields. However, all commercialized CS is extracted from animal tissues, which is associated with many problems, such as...

Influenza A virus (IAV) and SARS-CoV-2 (COVID-19) cause pandemic infections where cytokine storm syndrome and lung inflammation lead to high mortality. Given the high social and economic cost of respiratory viruses, there is an urgent need to understand how the airways defend against virus infection. Here we use mice lacking the WD and linker domains of ATG16L1 to demonstrate that ATG16L1dependent targeting of LC3 to single-membrane, non-autophagosome compartmentsreferred to as non-canonical autophagyprotects mice from lethal IAV infection. Mice with systemic loss of non-canonical autophagy are exquisitely sensitive to low-pathogenicity IAV where extensive viral replication throughout the lungs, coupled with cytokine amplification mediated by plasmacytoid dendritic cells, leads to fulminant pneumonia, lung inflammation and high mortality. IAV was controlled within epithelial barriers where non-canonical autophagy reduced IAV fusion with endosomes and activation of interferon signalling. Conditional mouse models and ex vivo analysis showed that protection against IAV infection of lung was independent of phagocytes and other leucocytes. This establishes non-canonical autophagy in airway epithelial cells as a novel innate defence that restricts IAV infection and lethal inflammation at respiratory surfaces.

Adjuvants can enhance vaccine immunogenicity and induce long-term enhancement of immune responses. Thus, adjuvants are important for vaccine research. Polysaccharides isolated from select Chinese herbs have been demonstrated to possess various beneficial functions and excellent adjuvant abilities. In the present study, the polysaccharides IIP-A-1 and IIP-2 were isolated from Isatis indigotica root and compared with the common vaccine adjuvant aluminum hydroxide via intramuscular co-administration of inactivated rabies virus rCVS-11-G into mice. Blood was collected to determine virus neutralizing antibody (VNA) titers and B and T lymphocyte activation status. Inguinal lymph node samples were collected and used to measure B lymphocyte proliferation. Splenocytes were isolated, from which antigen-specific cellular immune responses were detected via ELISpot, ELISA and intracellular cytokine staining. The results revealed that both types of polysaccharides induce more rapid changes and higher VNA titers than aluminum hydroxide. Flow cytometry assays revealed that the polysaccharides activated more B lymphocytes in the lymph nodes and more B and T lymphocytes in the blood than aluminum hydroxide. Antigen-specific cellular immune responses showed that IIP-2 strongly induced T lymphocyte proliferation in the spleen and high levels of cytokine secretion from splenocytes, whereas aluminum hydroxide induced proliferation in only a small number of lymphocytes and the secretion of only small quantities of cytokines. Collectively, these data suggest that the polysaccharide IIP-2 exhibits excellent adjuvant activity and can enhance both cellular and humoral immunity.

Objective: To evaluate the state of evidence for the beneficial and harmful effects of Tai Chi on non-motor disorders in post-stroke patients. Design: Systematic review and meta-analysis of published studies. Subjects: Stroke survivors who received conventional rehabilitation therapy or Tai Chi training. Data sources: We searched seven electronic literature databases and one clinical registry platform to collect data from randomized controlled trials published up to July 26, 2020. Results: A total of 11 randomized controlled trials with 723 stroke survivors met the inclusion criteria, of which six were included in the meta-analysis. Among the 11 studies, one was assessed as “low”, eight were assessed as “moderate”, and only two were assessed as “high” for the assessment of methodologic quality. Compared to patients who received conventional rehabilitation therapy, those who received Tai Chi training showed greater improvement in scores of depression (standardized mean difference (SMD) [95% confidence interval (CI)] = 0.36 [0.10, 0.61], Grading of Recommendations Assessment, Development, and Evaluation [GRADE]: very low). There were no differences in the improvements in post-stroke global mental disorders (mean difference (MD [95% CI] = 6.15 [−3.05, 15.36], GRADE: moderate) or sleep disorders (MD [95% CI] = 0.33 [−1.51, 1.81], GRADE: low) between Tai Chi and control groups. Conclusion: Tai Chi may alleviate post-stroke depression in stroke survivors but has no clear effects on post-stroke cognitive and sleep disorders.

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