Phylogenetic analysis of the genomes of two strains of human adenovirus type 3

Human adenovirus type 3 （HAdV-3） is widely prevalent all over the world, especially in Asia. The objective of this study is to carry out complete genomic DNA sequencing and the phylogenetic analysis for two strains （Guangzhou01 and Guangzhou02） of HAdV-3 wild virus isolated from South China. Nasopharyngeal secretion aspirate specimens of sick children were inoculated into HEp-2 and HeLa culture tubes, and the cultures were identified by neutralization assay with type-specific reference rabbit antiserum. Type-specific primers were also utilized to confirm the serotype. The restriction fragments of HAdV genome DNA were cloned into pBlueScript SK （ ＋ ） vectors and sequenced, and the 5＇ and 3＇ ends of the linear HAdV-3 genome were directly sequenced with double purified genomic DNA as templates. General features of the HAdV-3 genome sequences were explored by using several bio-software. Phylogenetic analysis was done with MEGA 3.0 software. The genomic sequences of Guangzhou01 and Guangzhou02 possess the same 4 early regions and 5 late regions and have 39 coding sequences and two RNA coding sequences. Other non-coding regions are conservative. Inverted repeats and palindromes were identified in the genome sequences. The genomes of group B human adenovirus as well as HAdV-3 have close phylogenetic relationship with that of chimpanzee adenovirus type 21. The genomic lengths of these two isolated strains are 35 273 bp and 35 269 bp, respectively. The phylogenetic analysis showed that HAdV-B species has some relationship with certain types of chimpanzee adenovirus.

Construction of recombinant adeno-associated viral vectors in human neurenergen-3 gene

BACKGROUND： Research of transgene brings hope for gene therapy of various diseases; in addition, some projects have been tested in clinic. Recently, the focus has been to find an ideal vehicle and a suitable therapeutic gene. OBJECTIVE： To explore an effective way to construct recombinant adeno-associated viral vectors expression in human neurnnergen-3 gene. DESIGN： Gene directed cloning. SETTING： Central Laboratory of Northern China Coal Medical College. MATERIALS： DH5a competent bacillus coli strain was provided by Capital Medical University; pCDNA3-NT-3 by professor Chen from Bengbu Medical College; pAAV-Laze, pAAV-Helper, pAAV-RC and pAAV-MCS plasmids by Capital Medical University; HEK293 cells by Cell Center of Basic Medical College of Tongji Medical University. METHODS： NT-3 genes which were selected from pCDNA3-NT-3 plasmids were cloned in pAAV-MCS to form a recombinant adeno-associated viral plasmid （pAAV-NT-3）. pAAV-NT-3, pAAV-RC, pAAV-LacZ and pHelper plasmids were extracted, purified and subjected to enzyme-shearing evaluation. In addition, pAAV-NT-3 and pAAV-LacZ were cotransfected with pHelper and pAAV-RC, respectively into AVV-293 cells with DNA mediated by calcium superphosphate transfection gene; and then, AVV-293 cells were packed into recombinant adeno-associated viral rAAV-NT-3 and rAAV-LacZ. After collection of viral particles, rAAV-LacZ viral stock solution was diluted based on ratio of 10：1 and the mixture was used to infect HT 1080 cells. X-gal stain was used to measure virus titer. MAIN OUTCOME MEASURES： Size of targeted gene fragments, validity of vehicle construction and virus titer. RESULTS： Targeted gene NT-3 was successfully inserted into the relative vehicle pAAV and pAAV-NT-3 was correctly recongnized by enzyme-shearing evaluation. Enzyme-shearing electrophoresis demonstrated that pAAV-NT-3, pAAV-RC, pAAV-LacZ and pHelper plasmids were successfully extracted and purified. β-galactoside staining in situ indicated that LacZ genes were expressed in human fibrosarcoma cells （HT1080） and the recombinant virus titer was measured as 1 ×10^12 virus particles per milliliter. CONCLUSION： Total-length cDNA fragment of NT-3 gene, which is obtained from pCDNA3-NT-3 plasmids, is closely matched to polyclone enzyme-shearing sites of adeno-associated viral vectors, while the combination can be used to construct recombinant adeno-associated viral vectors expression in hNT-3 gene.

Construction and Characterization of a Novel Recombinant Attenuated and Replication-Deficient Candidate Human Adenovirus Type 3 Vaccine:"Adenovirus Vaccine Within an Adenovirus Vector"

Human adenoviruses(HAd Vs)are highly contagious and result in large number of acute respiratory disease(ARD)cases with severe morbidity and mortality.Human adenovirus type 3(HAd V-3)is the most common type that causes ARD outbreaks in Asia,Europe,and the Americas.However,there is currently no vaccine approved for its general use.The hexon protein contains the main neutralizing epitopes,provoking strong and lasting immunogenicity.In this study,a novel recombinant and attenuated adenovirus vaccine candidate against HAd V-3 was constructed based on a commercially-available replication-defective HAd V-5 gene therapy and vaccine vector.The entire HAd V-3 hexon gene was integrated into the E1 region of the vector by homologous recombination using a bacterial system.The resultant recombinants expressing the HAd V-3 hexon protein were rescued in AD293 cells,identified and characterized by RT-PCR,Western blots,indirect immunofluorescence,and electron microscopy.This potential vaccine candidate had a similar replicative efficacy as the wild-type HAd V-3 strain.However,and importantly,the vaccine strain had been rendered replication-defective and was incapable of replication in A549 cells after more than twentygeneration passages in AD293 cells.This represents a significant safety feature.The mice immunized both intranasally and intramuscularly by this vaccine candidate raised significant neutralizing antibodies against HAd V-3.Therefore,this recombinant,attenuated,and safe adenovirus vaccine is a promising HAd V-3 vaccine candidate.The strategy of using a clinically approved and replication-defective HAd V-5 vector provides a novel approach to develop universal adenovirus vaccine candidates against all the other types of adenoviruses causing ARDs and perhaps other adenovirus-associated diseases.