In 1982, a foreign gene successfully expressed in the vaccinia virus WR strain (mouse neurotropic strain) aroused a great concern of Chinese scientists. In 1984, Dr. ZHU Ji-Ming, academician of Chinese Academy of Science organized a collaborative research group in the Institute of Virology, Chinese Academy of Medical Science to develop a novel gene expression system based on vaccinia virus Tiantan strain which was used to prepare smallpox vaccine for human use more than 50 years in China. After more than ten years of effort, a highly efficient vector system for foreign gene expression was successfully established and widely used for the expression of foreign genes, for recombinant vaccines, and the development of monoclonal antibodies and diagnostic reagents. This paper briefly described the study and application of the gene expression system and discussed the problems and prospects of vector vaccine development.

In 1982 , a foreign gene successfully expressed in the vaccinia virus WR strain (mouse neurotropic strain) aroused a great concern of Chinese scientists. In 1984, Dr. ZHU Ji-Ming, academician of Chinese Academy of Science organized a collaborative research group in the Institute of Virology, Chinese Academy of Medical Sciences to develop a novel gene expression system based on vaccinia virus Tiantan strain which was used to prepare smallpox vaccine for human use more than 50 years in China. After more than ten years of effort, a highly efficient vector system for foreign gene expression was successfully established and widely used for the expression of foreign genes, recombinant vaccines, and the development of monoclonal antibodies and diagnostic reagents. This paper briefly described the research and application of the gene expression system and discussed the problems and prospects of vector vaccine development.

The purpose of the current study is to develop a mouse model for exploration of the pathogenesis of dengue virus (DENV) infection. HepG2 cells were transplanted to severe combined immunodeficiency (SCID) mice intraperitoneally to develop a HepG2-SCID mouse chimera model. To confirm the successful transplantation , the concentration of human albumin (hALB) in the serum was determined by sandwich enzyme-linked immunosorbent assay. Following challenge with intraperitoneal injection of DENV2, HepG2- SCID mice were evaluated by detection of virus distribution and histological changes in major organs. HepG2 cells engrafted into SCID mouse could support the replication of DENV2. HepG2-SCID mouse showed viremia and severe organ injuries. The data suggest that DENV2-infected HepG2-SCID chimera model is developed successfully , which would provide a useful tool for studying pathogenesis of DENV infection.

A total of 49 subjects with human immunodeficiency virus (HIV) antibody-indeterminate in Dehong Dai and Jingpo Nationality Autonomous Prefecture of Yunnan Province from 2008 to 2011 were analyzed. The population distribution, Western blotting (WB) bands and follow-up results of antibody were investigated to reveal the existing problems and possible improvement. All the subjects were from the HIV Confirmatory Laboratory of Dehong Dai and Jingpo Nationality Autonomous Center for Disease Control and Prevention and the results were decided by the National Guideline for Detection of HIV/AIDS (2009 Edition). 49 (2.00%) cases with indeterminate HIV antibody in 2452 samples were found, mainly in the population of voluntary counseling and testing (26.53%). The ratio of S/CO was distributed from <1 to ≥10, but the seroconversion rate of cases with S/CO≥10 was as high as 83.33% (5/6). The main bands were p24 and gp160. 27 patients were successfully followed up, of which 8 turned positive. The positive conversion rate was 29.63%（8/27）. As indeterminate HIV antibody results may exist in window period of HIV infection in patients with other diseases and even healthy people in certain physiological periods, all the laboratory procedures need good quality control. Other detection methods and epidemiological survey of acquired immunodeficiency syndrome (AIDS) should be combined to make accurate diagnosis.

In the present study, the influence of Salmonella enterica serovar Typhi (S. typhi) plasmid pRST98 on autophagy of human-derived macrophage-like cell line THP-1 was investigated. THP-1 cells were infected with wild type strain (ST6), mutant strain (ST6-ΔpR_ST98) and ST6-ΔpR_ST98 with a complemented plasmid encoding pR_ST98 (ST6-c-pR_ST98), and the lysosomotropic agent chloroquine (CQ) was added for intervention. First, the appropriate concentration of CQ was determinated by detecting the influence of CQ on cells and bacteria respectively. The cells were collected at different time points after cocultivation with bacteria. The changes of protein LC3Ⅱ, p62, autophagosome and autolysosomes were detected by Western blotting and monomeric red fluorescent protein-green fluorescent protein (mRFP-GFP)-LC3 plasmid transfection. The results revealed that 30 μmol/L CQ could significantly block the autophagic process, and had no obvious influence on the cells and bacteria. The Western blotting analysis showed that the augment of autophagy protein LC3Ⅱ and p62 in ST6-ΔpR_ST98 group was higher than those in ST6 and ST6-c-pR_ST98 groups after CQ treatment. Similarly, the LC3 dots in the groups treated with CQ were higher than those in the groups without CQ treatment. Specifically, even more remarkable level of LC3 dots in ST6-ΔpR_ST98 group than that in the wild type group was observed. All these evidences suggested that S. typhi plasmid pR_ST98 works in the early stage of autophagy, prior to degradation in autolysosomes.

In order to analysis the clinical characteristic of necrotizing pneunomia in children, a retrospective investigation of the clinical manifestations, radiological findings, pathology, microbiology, clinical courses and outcomes of 9 children (6 males, 3 females) with necrotizing pneumonia was performed. The age range was 1-7 years (average 3.5 years). The duration of fever was 11-43 d (average 22 d). Four cases received mechanical ventilation. There were 5 cases with microbiological identification, 2 cases with Streptococcus pneumoniae, 2 cases with Mycoplasma pneumoniae and 1 case with Pseudomonas aeruginosa. The chest CT scans showed pneumonic lobar consolidation and pleural effusion in 9 cases, and small cavities in the consolidation regions in 8 cases. All 9 patients received surgical intervention, 7 with wedge resection, 1 with segmentectomy, and 1 with lobectomy. All the specimens exhibited parenchymal necrosis and acute inflammatory infiltration. All 9 patients survived. Seven patients had full clinical resolution within 6 months, and 2 patients resolved in 10 months. Streptococcus pneumoniae and Mycoplasma pneumoniae were found to be the predominant pathogens in children with necrotizing pneumonia. The chest CT scan is crucial in the diagnosis. The prognosis is good after antibiotic and surgical therapy.

Sequence analysis of human enterovirus (HEV) is now widely applied. The technology of sequencing-based identification and typing of HEV is reviewed in the present paper.

Coronaviruses generally infect their natural hosts but scarcely infect other species of animals. The interspecies transmission of coronaviruses depends on the interaction of spike protein with the receptor. Receptor binding domains as well as other domains in spike proteins are mainly related to the tropism of coronaviruses. The emergence of new and host-across strains of coronaviruses is due to the huge RNA genome, specific subgenomic RNAs and high recombinant rate between RNAs. And both persist infection and co-infection provided the opportunities for the recombinant events and sequential host-shifting.

The potential connection between human adenovirus type 36 (Ad-36) infection and obesity has received extensive research attentions in recent years. Studies indicated that Ad-36 antibody may be associated with body mass index (BMI) in obesity population, and the results were further confirmed in animal model and in vitro cellular models. Viral E4 orf-1 gene, cellular adipocyte differentiation pathway and phosphatidylinositol 3-kinase (PI3K) signaling pathways are current focal points of mechanism studies. Since limited data is available, more epidemiological data and mechanism studies are needed to confirm the relationship between Ad-36 infection and obesity.

The assembly mechanism of human cytomegalovirus (HCMV) is one of the focal points of research; and the answer to this may provide new targets for intervention. The assembly process consists of two stages. The first stage begins in the cytoplasm where assembly protein precursor (pAP), protease precursor (pPR) and minor capsid protein (mCP) interact with each other and form diverse complexes. The complexes enter into the nucleus and finally form a DNA-containing nucleocapsid. In the second stage, the nucleocapsids will get tegument and envelope. It’s a complicated process involved a variety of proteins and host cells. It’s worth mentioning that structure/function defects of viral proteins may lead to the failure of assembly. The recent researches on the mechanism of assembly of HCMV are reviewed in the present paper.

Helicobacter pylori (Hp) infection is the main reason for the chronic active gastritis and peptic ulcer in children. Increased evidences show that Hp plays an important role in a variety of extraintestinal diseases in children as well. There is a close relationship between Hp infection and iron deficiency anemia, idiopathic thrombocytopenic purpura and growth retardation. In this article, the correlation between Hp infection and several extraintestinal diseases is reviewed.