Shaohui Ma

The repairing effect of a recombinant human connective‐tissue growth factor in a burn‐wounded rhesus‐monkey (Macaca mulatta) model

CTGF (connective‐tissue growth factor) has been characterized as an extracellular‐matrix‐associated protein that modulates basic‐fibroblast‐growth‐factor signalling and angiogenesis. In the present paper, the cloning of the ctgf gene from human umbilical‐vein endothelial cells and expression of the protein in Escherichia coli as an N‐terminal hexahistidine fusion protein is described. Recombinant human CTGF (rhCTGF) was expressed and purified so that we could investigate its effect on the proliferation of human embryo fibroblast KMB‐17 and NIH3T3 cells. The results indicated not only that the protein was properly folded, but also that it had the same specific activity and stability as the native protein. Furthermore, we administered this recombinant protein in a non‐human primate [rhesus monkey (Macaca mulatta)] burn‐wound model and report the clinical findings and structural effects. Epitheliotrophic effects were conspicuous in wounded tissues at 10–100 ng of CTGF/cm2, suggesting that administered rhCTGF can play a normal physiological role in wound repairing in a non‐human primate model.

A comparison of the biological characteristics of EV71 C4 subtypes from different epidemic strains

The comparative analysis of the biological characterization and the genetic background study of EV71 circulating strains is commonly recognized as basic work necessary for development of an effective EV71 vaccine. In this study, we sequenced five EV71 circulating strains, isolated from Fuyang, Hefei, Kunming and Shenzhen city of China and named them FY-23, FY-22, H44, K9 and S1 respectively. The sequence alignment demonstrated their genotypes be C4. The genetic distance of the VP1 gene from these isolates suggested that they were highly co-related with genetic identity similar to other previously reported EV71 strains in China. Additionally, these strains were identified to display some obvious proliferation dynamics and plaque morphology when propagated in Vero cells. However, a distinctive difference in pathogenic ability in neonatal mice was found. Some differences in cross neutralization test & immunogenic analysis were also found. All these results are related to the biological characterization of circulating EV71 strains in China and aid in the development of an EV71 vaccine in the future.

Genetic analysis of the VP1 region of human enterovirus 71 strains isolated in Fuyang, China, during 2008

Enterovirus 71 (EV71) is a common cause of Hand, foot, and mouth disease (HFMD) and may also cause severe neurological diseases, such as encephalitis and poliomyelitis-like paralysis. To examine the genetic diversity of EV71, we determined and analyzed the complete VP1 sequences (891 nucleotides) from nine EV71 strains isolated in Fuyang, China. We found that nine EV71 strains isolated were over 98% homologous at the nucleotide level and 93%–100% homologous to members of the C4 subgenogroup. At the amino acid level, these Fuyang strains were 99%–100% homologous to one another, 97%–100% homologous to members of the C4 subgenogroup, and the histidine(H) at amino acid position 22 was conserved among the Fuyang strains. The results indicate that Fuyang isolates belong to genotype C4, and an H at position 22 appears to be a marker for the Fuyang strains.

Immunogenicity and safety of a novel formalin-inactivated and alum-adjuvanted candidate subunit vaccine for mumps

While an attenuated vaccine against mumps has played a role in controlling the epidemic of this disease worldwide, some problems with efficacy and safety of the vaccine are still present. In the work described here, a novel mumps vaccine with good immunity and safety was developed by selecting an antigen component of the mumps virus. The results suggest that this purified antigen vaccine is immunogenic in animals and is capable of inducing a specific neutralizing antibody response against viral HN, but not against other viral proteins. The clinical and pathological observations after challenge of vaccinated rhesus monkeys indicated further that the immune response induced by this vaccine provided complete protection from wild-type virus infection. Furthermore, the immunological analysis and clinical observation of experimental monkeys that were immunized with the vaccine, followed by infection with wild-type virus, suggest that no abnormal changes in expression of inflammatory cytokines and no clinical allergic reaction were found at 1 month after challenge.

The interaction of the SARS coronavirus non-structural protein 10 with the cellular oxido-reductase system causes an extensive cytopathic effect

Abstract The pathological mechanism of SARS-CoV infection was investigated. The gene for the SARS-CoV non-structural protein 10, which is located in the open reading frame of pp1a/pp1ab gene, was synthesized and used to screen for the specific cellular gene coding for the protein interacting with this nsp10 protein in a human embryo lung cDNA library using a yeast trap method. The results indicated that apart from the two subunits of cellular RNA polymerase complex, BTF3 and ATF5, this nsp10 protein was also able to interact specifically with the NADH 4L subunit and cytochrome oxidase II. Further study revealed that the activity of the NADH-cytochrome was altered and the inner mitochondrial membrane was depolarized in the transfected human embryo lung fibroblast by the nsp10 protein gene. The cytopathic effect of the Coronavirus 229E strain appeared more extensive in these cells than in the control cells.

Identification and development of a promising novel mumps vaccine candidate strain

Mumps epidemics are usually caused by airborne transmission of mumps virus (MuV) and have high morbidity in non-immunized children. Epidemiological studies in many regions of China show that the genotype F viral strain is the most prevalent. However, the genotype A strain is currently used to prepare vaccines. Regional epidemiological MuV data suggest a significant application for the development of live attenuated mumps vaccines targeting specific genotypes. This article reports the isolation and culture of a genotype F MuV candidate strain that could be used to prepare a live attenuated mumps vaccine. This strain is shown to have good immunological efficacy and stability in neurovirulence evaluations. This work should facilitate the implementation of mumps vaccination in mainland China by targeting the most prevalent MuV genotype, genotype F.

Dynamic constitution of the pathogens inducing encephalitis in hand, foot and mouth disease in Kunming, 2009-2011

Hand, foot and mouth disease (HFMD), caused by various viral pathogens, is an emerging infectious disease in children in Asia. Understanding the composition of these pathogens is necessary to prevent and control this disease. In the present study, the pathogens in 436 HFMD patients (from 2009 to 2011) with concurrent clinical indications of encephalitis, meningoencephalitis, or both, were defined using the semi-nested PCR. A systematic analysis of the composition of these pathogens was performed. Various enteroviruses that are capable of inducing central nervous system (CNS) damage in HFMD patients were identified, including enterovirus 71, coxsackievirus A16, and Echovirus 9. Most of these pathogens were found co-infecting the patients. The composition of the pathogens that induced CNS damage in the HFMD patients was dynamically modulated in the cases.

Molecular characterization of two novel echovirus 18 recombinants associated with hand-foot-mouth disease

Human echovirus 18 (E-18) is a member of the enterovirus B species. To date, sixteen full-length genome sequences of E-18 are available in the GenBank database. In this study, we describe the complete genomic characterization of two E-18 strains isolated in Yunnan, China. Pairwise comparisons of the nucleotide sequences and the deduced amino acid sequences revealed that the two Yunnan E-18 strains had 87.5% nucleotide identity and 96.3–96.5% amino acid identity with the Chinese strain. Phylogenetic and bootscanning analyses revealed the two E-18 strains had the highest identity with other several EV-B serotypes than the other E-18 strains in the P3 coding region, especially, 3B region of the Swine Vesicular disease virus (SVDV) strain HK70, indicated that frequent intertypic recombination might have occurred in the two Yunnan strains. This study contributes the complete genome sequences of E-18 to the GenBank database and provides valuable information on the molecular epidemiology of E-18 in China.

A severe case of co-infection with Enterovirus 71 and vaccine-derived Poliovirus type II

Enterovirus 71 (EV71) is often identified as the primary pathogen that directly leads to severe cases of HFMD, whereas the association between other enteroviruses and EV71 infection remains largely unclear. Here we report a rare case of a 5-year-old boy co-infected with EV71 and vaccine-derived Poliovirus (VDPV) type II, which were identified based on PCR and sequence analysis results and clinical symptoms and were characterized on CT. We determined that the EV71 strain belongs to the C4 subtype, and the VDPV II strain was closely genetically related to the reference Sabin type II strain. This report may improved our understanding of the clinical significance of the associations between clinical signs and the infectious properties of the involved pathogens.

Molecular evolution of two asymptomatic echovirus 6 strains that constitute a novel branch of recently epidemic echovirus 6 in China

BackgroundEchovirus 6 (E6) infections are associated with aseptic meningitis and acute flaccid paralysis (AFP). But some infections, sometimes most of them, are asymptomatic. The mechanism of E6 virulence is unknown. Analyses of the molecular evolution of asymptomatic E6 may help understand why the infections show different manifestations.MethodsNinety-six stool samples of healthy children in Yunnan, China were collected and two E6 strains were isolated from them. The whole genomes of these two E6 strains were sequenced, and their molecular evolution was analyzed.ResultsThe results showed that the two E6 strains may be derived from KJ7724XX strains, which were predominant in AFP patients in Shangdong in 2011. The evolution was accelerated when the two E6 strains formed, although no positive selection site was found. The 11 exclusive mutations on which selection force significantly changed were found in the 2C, 3AB and 3C genes.ConclusionThere are some E6 strains which did not cause the disease in the children of Yunnan. These E6 strains maybe come from a recombinant E6 strain which was associated with the outbreak of AFP in Shangdong in 2011. However, some new mutations were found in the 2C, 3AB and 3C genes of these asymptomatic strains, and these mutations may be constraint by the natural selection and could be potentially responsible for clinical presentations.