Construction and sequencing of full-length cDNA of peste des petits ruminants virus / 病毒学报

To develop a reverse genetics system of Peste des petits ruminants virus(PPRV), five pairs of oligonucleotide primers were designed on the basis of the full-length genomic sequence of PPRV Nigeria 75/ 1 strain. Using RT-PCR technique, five over-lapping cDNA fragments, designated as JF1, JF2, JF3, JF4 and JF5, respectively, were amplified, followed by cloning into pcDNA3.1(+)vector. An AscI restriction enzyme site and a T7 promoter sequence were introduced immediately upstream of 5'-end, while a PacI restriction enzyme site was engineered downstream of 3'-end. Using pok12 as a plasmid vector, the full-length cDNA clone pok12-PPRV of Nigeria 75/1 was assembled by connecting the five cDNA fragments via the unique restriction endonuclease site of PPRV genome. The resultant nucleotide sequence of the PPRV Nigeria 75/1 strain in the study was compared with other members of genus morbillivirus, and phylogenetic analysis was used to examine the evolutionary relationships. The results showed that PPRV Nigeria 75/ 1 was antigenically closely related to Rinderpest virus and Measles virus. Successful construction of full-length cDNA clone of PPRV Nigeria 75/1 strain lays the basis rescuing PPRV effectively and enables further research of PPRV at molecular level.

Construction, expression and immunogenicity of eukaryotic vectors based on goat pox virus P32 gene / 病毒学报

The full-length P32 gene and the truncated P32 gene (MP-32) were amplified from the recombinant plasmid pMD-P32 by polymerase chain reaction (PCR) and cloned into pcDNA3. 1(+) and pcDNA3.1-CpG respectively. The recombinant plasmids (pcDNA3.1-P32, pcDNA3.1-CpG-P32 and pcDNA3. 1-CpG-MP32) were transfected into BHK-21 cells by using lipofectin. The expressed P32 protein was confirmed by indirect immunofluorescence assay (IFA). The BALB/c mice were immunized with these recombinant plasmids by intramuscular injection. The specific antibodies aginst CPV were detected by ELISA kit weekly. The murine splenic T lymphocyte subgroups CD4+ and CD8+ were detected by flow cytometry. Results showed that the P32 protein was expressed successfully in vitro. After 2 weeks post im munization, the specific IgG antibodies against CPV were detected in the vaccinated mice. The percentage of CD4+ /CD8+ T cells was significantly higher than that of the control. In conclusion, these constructed eukaryotic vectors could induce humoral and celluar immune responses in mice.

Cloning and sequence analysis of cDNA encoding porcine alphav subunit for FMDV receptor / 生物工程学报

Receptors play a crucial role in determining the pathogenesis and tissue tropism of virus. Foot-and-mouth disease virus (FMDV) has been showed to use four integrins, alphavbeta1, alphavbeta3, alphavbeta6 and alphavbeta8 as receptors to initiate infection. In this study, the porcine integrin alphav gene was cloned by RT-PCR from the lung tissue of healed pig infected experimently with FMDV, and compared its nucleotide and deduced amino acid sequence with the av gene of other animals. The 3141bp cDNA of bovine integrin alphav encodes a polypeptide of 1046 amino acids consisting of a 30-residue putative signal peptide, a 955-residue ectodomain, a 29-residue transmembrane domain, and a 32-residue cytoplasmic domain. The ectodomain contains 11 potential N-linked glycosylation sites (NXT/NXS), 2 calcium binding domains (DX[D/N] XDGXXD) and 18 cysteine residues. The nucleotide sequence similarities of integrin alphav between pig and cattle, human, rheses monkey, house mouse, chicken, dog are 93.3%, 91.5%, 91.4%, 85.6%, 73.2% and 89.9% respectively; and the amino acid sequence similarities are 96.3%, 94.6%, 94.1%, 90.8%, 81.6% and 93.8%, respectively. The alphav gene of cattle and pig exhibited the highest sequence homology. It is possible that host tropism of FMDV may related to divergence in receptors among different species.

Molecular Characteristics of cDNA Encoding Bactrian Camel ?6 Subunit for FMDV Receptor / 中国生物工程杂志

Receptors play a crucial role in determining the host specificity and tissue tropism of virus. Foot-and-mouth disease virus(FMDV)has been showed to use four integrins, ?v?1, ?v?3, ?v?6 and ?v?8 as receptors to initiate infection and ?v?6 functions as the major receptor.The cDNA encoding bactrian camel integrin ?6 from the lung tissue was cloned and sequenced. The 2367bp cDNA of bactrian camel integrin ?6 encodes a polypeptide of 788 amino acids consisting of a 26-residue putative signal peptide, a 681-residue ectodomain with 8 potential N-linked glycosylation sites and 58 cysteine residues, a 29-residue transmembrane domain, and a 52-residue cytoplasmic domain with a NPLY motif and 1 potential N-linked glycosylation site. The nucleotide sequence similarity of integrin ?6 between bactrian camel and cattle, pig, sheep, human, mouse, Norway rat is 91.1%、91.8%、90.6%、90.5%、83.7%、84.1%, and the amino acid sequence similarity is 94.3%、93.4%、93.4%、93.7%、88.7%、88.6%, respectively. The bactrian camel ?6 gene exhibited the higher sequence homology with the ?6 gene of cattle, pig and sheep, indicating their close genetic relationships. It is possible that host tropism of FMDV may related to divergence in ?6 receptors among different species.

High-level expression of the potential vaccine antigen TSO18 of Taenia solium in Pichia pastoris / 生物工程学报

TSO18 gene was subcloned into the Pichia pastoris expression vector pPIC9K. The recombinant plasmid pPIC9K-TSO18 was transformed into P. pastoris GS115 by electroporation so that the plasmid will be integrated with chromosome of P. pastoris. The P. pastoris strains containing multi-copy recombinant were screened by G418 and induced by methanol. The expression product was analyzed by SDS-PAGE, Western blot, deglycosylation, and purified by Sephadex column, and was used to immunize mice. The results indicated that the target protein was efficiently expressed in P. pastoris, and glycosylated moderately, and had immunological activity. In a 5 liter fermentor, the expression level of the target protein was up to 2.54 mg/mL. These results will benefit for the development of genetically engineering vaccine.

Expression of phosphoprotein P2 of Cysticercus cellulosae in Pichia pastoris and its application / 生物工程学报

Cysticercosis is caused by the metacestode form of Taenia solium-Cysticercus cellulosae and it causes great economic losses and threatens the people's health. There are some problems on how to control cysticercosis, in order to resolve the key problem that the native antigen to diagnose and prevent cysticercosis is very limited and is not satisfied, Pichia pastoris Expression System was used to express recombinant P2 protein. The interested P2 gene was got by digesting the pGEM - P2 vector using restriction endonuclease, then it was inserted into the secretory pPIC9K Pichia pastoris expression vector and transformed into E. coli. Positive recombinant plasmids were selected sequenced and named pPIC9K-P2 and it was linearized by Sal I and Bgl II, then the linear DNA transfored into Pichia pastoris GS115 by electroporation. The recombinant expression vector pPIC9K - P2 integrated into GS115 via homologous recombination between the transforming DNA and regions of homology within the genome. The transformants were screened for multicopy recombinants using G418 and were distinguished for Mut phenotypes by MD and MM. Two different phenotypes were generated-HIS+ MUT+ (Methanol utilization plus) and HIS+ MUT(S) (Methanol utilization slow). PCR analysis of the multicopy recombinants indicated that the P2 gene was integrated within the genome of pichia Pastoris. The multicopy recombinants were named GS115/pPIC9K - P2HIS+ MUT+ and GS115/pPIC9K-P2HIS+ MUT(S), both HIS+ MUT+ and HIS+ MUT(S) were induced with methanol. The results of SDS-PAGE and Western blot demonstrated that the culture supernatant of the induced Pichia pastoris contained P2 protein which was accumulated up to 33 % of total proteins in the culture supernant and its molecular weight is 12.6kD. The results of the clinical study indicated that the expression P2 protein could be used to diagnose human cysticercosis and swine cysticercosis as diagnosis antigen.

Heparan Sulfate and Foot-and-mouth Disease Virus Infection / 微生物学通报

Receptors are primary determinant of viral tropism and disease pathogenesis.Heparan sulfates (HS)are ubiquitous,polyanionic carbohydrate chains linked to core proteins in cell membranes and ex- tracellular matrices of all eukaryotes.HS have also been demonstrated to function as receptors or co-receptors for a number of different viruses.To date,HS and four RGD-dependent integrins,?v?3,?v?6, ?v?1,and?v?8 have been reported to serve as receptors for Foot-and-mouth disease virus(FMDV).Different receptors may be used to interact with host cells during FMDV infection.Studies on the structure and function of receptors are very important for understanding the interaction between host cells and FMDV. Here,We mainly reviews the progress on the biological characteristics of HS and its roles in FMDV infection.

Integrin and Foot-and-mouth Disease Virus Infection / 微生物学通报

Integrins are a family of cell surface glycoproteins that contribute to a variety of biological functions, including cell growth, migration, proliferation and morphology. In addition, integrins also play the important roles in pathological process. Several viruses have been showed to use integrins as receptors or co-receptors to infect host cells.This article mainly reviews the progress on integrins and their roles in FMDV infection.