Construction, screening and immunogenicity of the recombinant poxvirus vaccine rVTTδTK-RBD against SARS-CoV-2 / 细胞与分子免疫学杂志

Objective To construct a recombinant poxvirus vector vaccine, rVTTδTK-RBD, and to evaluate its safety and immunogenicity. Methods The receptor-binding domain (RBD) gene was synthesized with reference to the gene sequence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and was inserted into the polyclonal site of the self-constructed recombinant plasmid pSTKE, to construct the recombinant poxvirus shuttle vector pSTKE-RBD. This was then transfected into BHK-21 cells pre-infected with the vaccinia virus Tiantan strain (VTT). The recombinant poxvirus rVTTδTK-RBD was successfully obtained after several rounds of fluorescence phage screening. The effect of rVTTδTK-RBD on the body mass of BALB/c mice was detected after immunizing mice by intra-nasal vaccination. The levels of specific and neutralizing antibodies produced by rVTTδTK-RBD on BALB/c mice were analyzed after immunizing mice intramuscularly. The effect of rVTTδTK-RBD on T cell subsets in BALB/c mice was detected by flow cytometry. Results Through homologous recombination, enhanced green fluorescent protein (EGFP) screening marker, and multiple rounds of fluorescent phosphorescence phage screening, a recombinant poxvirus rVTTδTK-RBD, expressing RBD with deletions in the thymidine kinase (TK) gene, was successfully obtained, which was validated by PCR. The in vivo experiments on BALB/c mice showed that rVTTδTK-RBD was highly immunogenic against SARS-CoV-2 and significantly reduced toxicity to the body compared to the parental strain VTT. Conclusion The recombinant poxvirus vaccine rVTTδTK-RBD against SARS-CoV-2 is successfully constructed and obtained, with its safety and immunogenicity confirmed through various experiments.

Progress on mRNA vaccine for the prevention of major infectious diseases in humans and animals / 生理学报

A large number of studies have demonstrated that mRNA vaccine has been characterized as a technique with good safety, strong immunogenicity and high developmental potential, which makes it have broad prospects in immunotherapy. In recent years, the stability and in vivo delivery efficiency of mRNA vaccines have been largely addressed by the progresses in mRNA engineering and delivery innovation. And some mRNA vaccines are now clinical approved or in preclinical trials. Here, we summarize current knowledge on the research advances, technology, and application in major infectious diseases in humans and animals of mRNA vaccines, with the aim to provide a reference for improving the development of novel mRNA vaccines.

Enhancing mucosal immunity in mice by recombinant adenovirus expressing major epitopes of porcine circovirus-2 capsid protein delivered with cytosine-phosphate-guanosine oligodeoxynucleotides

A recombinant replication-defective adenovirus expressing the major epitopes of porcine circovirus-2 (PCV-2) capsid protein (rAd/Cap/518) was previously constructed and shown to induce mucosal immunity in mice following intranasal delivery. In the present study, immune responses induced by intranasal immunization with a combination of rAd/Cap/518 and cytosine-phosphate-guanosine oligodeoxynucleotides (CpG ODN) were evaluated in mice. The levels of PCV-2-specific IgG in serum and IgA in saliva, lung, and intestinal fluids were significantly higher in the group immunized with rAd/Cap/518 and CpG ODN than animals immunized with rAd/Cap/518 alone. The frequencies of IL-2-secreting CD4+ T cells and IFN-gamma-producing CD8+ T cells were significantly higher in the combined immunization group than mice immunized with rAd/Cap/518 alone. The frequencies of CD3+, CD3+CD4+CD8-, and CD3+CD4-CD8+ T cells in the combined immunization group were similar to that treated with CpG ODN alone, but significantly higher than mice that did not receive CpG ODN. PCV-2 load after challenge in the combined immunization group was significantly lower than that in the phosphate-buffered saline placebo group and approximately 7-fold lower in the group treated with CpG ODN alone. These results indicate that rAd/Cap/518 combined with CpG ODN can enhance systemic and local mucosal immunity in mice, and represent a promising synergetic mucosal vaccine against PCV-2.

Construction of a recombinant plasmid harbouring the glyceraldenyde-3-phosphate dehydrogenase gene of periodic Brugia malayi and observation on DNA immunity.

Purpose: Controlling and eliminating lymphatic filariasis will require further research of preventative measures and implementation. Parasite is dependent on glycolysis for ATP production. The glycolytic enzyme glyceraldenyde-3-phosphate dehydrogenase (GAPDH) plays an important role in glycolysis and therefore is either a potential target for anti-parasite drug development or a vaccine candidate. Therefore, we tried to investigate the DNA vaccine-elicited immune responses in BALB/c mice. Materials and Methods: We cloned a gene encoding the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) from periodic Brugia malayi into vector pcDNA3.1. Mice were injected at a dosage of 100 μg recombinant plasmid DNA with CpG intramuscular injection and immunized three times at 2-week intervals. pcDNA3.1 and normal saline were used as control. The tissue of muscles at the 4 weeks after the third injection was collected and target genes were detected using RT-PCR. The humoral responses elicited in mice by inoculation with the recombinant plasmid pcDNA3.1-BmGAPDH were detected using a standard ELISA. Two weeks after the third immunization, stimulation index (SI) was measured using the MTT method and the level of secreted IL-4 and INF-g were detected using ELISA. Results: Specific gene fragment coding GAPDH was amplified and the recombinant plasmid pcDNA3.1-BmGAPDH was constructed. Post-challenge sera from the mice immunized with the DNA vaccine had specific antibody titres of 1:1600 to 1:6400, and the highest titre was observed in the mice that were inoculated by pcDNA3.1-BmGAPDH/CpG at 6 weeks. At 4 weeks after immunization, the spleens of the mice were obviously enlarged. The proliferation of spleen T lymphocytes seen on the MTT assay was higher in the pcDNA3.1-BmGAPDH group than in the control group (P value <0.05). The levels of IL-4 and INF-g in serums from the immunized mice were significantly higher than that of the control (P value <0.05). Conclusions: We conclude that the recombinant eukaryotic plasmid pcDNA3.1-BmGAPDH could elicit humoral and cellular immune responses in mice.

Molecular cloning and expression of EG95 gene of Iranian isolates of Echinococcus granulosus

Echinococcosis or hydatidosis is a chronic, zoonotic worldwide infection that occurs by the larval stages of taeniid cestodes of the genus Echinococcus. Iran is known as endemic region for this infection in the world. Vaccination has been considered as a good prevention method for this disease. Recombinant vaccines containing EG95 protein, against E. granulosus, has shown a high degree of protection against E. granulosus infection. In this study EG95 gene was extracted from Iranian isolates of E. granulosus and then cloned and expressed in expression vector. Protoscoleces were collected from sheep hydatid cysts. Then DNA and RNA were extracted from protoscoleces, and amplified by PCR and RT-PCR with specific primer. Afterward the purified RT-PCR products were successfully ligated into pTZ57R/T plasmid vector. The pcDNA3 plasmid was used as expression vector and Eg95 fragment sub cloned into this plasmid. The pcEG95 plasmid was digested by restriction enzymes to confirm cloning of this gene in pcDNA3 plasmid. In last step, the subcloned gene was expressed in CHO as eukaryotic cell. EG95 fragment successfully was subcloned in pcDNA3 and EG95 protein was expressed by eukaryotic cell. The recombinant EG95 protein was confirmed by SDS-PAGE and Western blot. Recombinant plasmid of pcEG95 was constructed successfully and express of recombinant EG95 protein was confirmed

[Determination and cloning of the gene encoding EG95 protein in Iranian isolate of Echinococcus granulosus]

Echinococcus granulosus is a cestode parasite that causes cystic hydatid disease in humans worldwide. The gene encoding EG95 protein may be a good candidate to design a DNA vaccine to prevent the disease. Considering the importance of EG95 gene and the scarceness of research on it in Iran, this study was carried out to determine and clone the gene encoding EG95 from Iranian isolate of E. granulosus.At the first stage, protoscoleces was isolated from hydatid cyst fluid and then RNA was extracted from protoscoleces and after performing RT-PCR, the amplified cDNA samples were detected by gel electrophoresis. In next stage, the obtained gene was cloned in pTZ57R/T vector. Two methods were used for conformation of cloning: colony PCR amplification and digestion with the EcoRI and XhoI restriction enzymes. Finally, the cloned EG95 gene in pTZ57R/T vector was sequenced. Homological comparison of sequences showed that cDNA of EG95 in Iranian isolate of E. granulosus had 492 bp and was different from the standard strain of EG95 reported from New Zealand and Australia [X90928.1]. Moreover, cloning of EG95 gene in pTZ57R/T plasmid was confirmed by digestion of this plasmid with the restriction enzymes. The EG95 gene was cloned in pTZ57R/T plasmid successfully and this plasmid can be used to design a DNA vaccine in further studies

Construction and growth properties of bovine herpesvirus type 5 recombinants defective in the glycoprotein E or thymidine kinase gene or both

Bovine herpesvirus type 5 (BoHV-5) is an important pathogen of cattle in South America. We describe here the construction and characterization of deletion mutants defective in the glycoprotein E (gE) or thymidine kinase (TK) gene or both (gE/TK) from a highly neurovirulent and well-characterized Brazilian BoHV-5 strain (SV507/99). A gE-deleted recombinant virus (BoHV-5 gE∆) was first generated in which the entire gE open reading frame was replaced with a chimeric green fluorescent protein gene. A TK-deleted recombinant virus (BoHV-5 TK∆) was then generated in which most of the TK open reading frame sequences were deleted and replaced with a chimeric â-galactosidase gene. Subsequently, using the BoHV-5 gE∆ virus as backbone, a double gene-deleted (TK plus gE) BoHV-5 recombinant (BoHV-5 gE/TK∆) was generated. The deletion of the gE and TK genes was confirmed by immunoblotting and PCR, respectively. In Madin Darby bovine kidney (MDBK) cells, the mutants lacking gE (BoHV-5 gE∆) and TK + gE (BoHV-5 gE/TK∆) produced small plaques while the TK-deleted BoHV-5 produced wild-type-sized plaques. The growth kinetics and virus yields in MDBK cells for all three recombinants (BoHV-5 gE∆, BoHV-5 TK∆ and BoHV-5 gE/TK∆) were similar to those of the parental virus. It is our belief that the dual gene-deleted recombinant (BoHV-5 gE/TK∆) produced on the background of a highly neurovirulent Brazilian BoHV-5 strain may have potential application in a vaccine against BoHV-5.

Protection of chickens from Newcastle disease with a recombinant baculovirus subunit vaccine expressing the fusion and hemagglutininneuraminidase proteins

Recombinant baculoviruses containing the fusion (F) and hemagglutinin-neuraminidase (HN) glycoprotein gene of the viscerotropic velogenic (vv) Newcastle disease virus (NDV) isolate, Kr-005/00, and a lentogenic La Sota strain of the NDV were constructed in an attempt to develop an effective subunit vaccine to the recent epizootic vvNDV. The level of protection was determined by evaluating the clinical signs, mortality, and virus shedding from the oropharynx and cloaca of chickens after a challenge with vvNDV Kr-005/00. The recombinant ND F (rND F) and recombinant HN (rND HN) glycoproteins derived from the velogenic strain provided good protection against the clinical signs and mortality, showing a 0.00 PI value and 100% protection after a booster immunization. On the other hand, the combined rND F + HN glycoprotein derived from the velogenic strain induced complete protection (0.00 PI value and 100% protection) and significantly reduced the amount of virus shedding even after a single immunization. The rND F and rND HN glycoproteins derived from the velogenic strain had a slightly, but not significantly, greater protective effect than the lentogenic strain. These results suggest that the combined rND F + HN glycoprotein derived from vvNDV can be an ideal subunit marker vaccine candidate in chickens in a future ND eradication program.

Analysis of Japanese encephalitis (JE) virus genome and implications for recombinant JE vaccine.

From the information of nucleotide sequences and deduced amino acid sequences of flaviviruses including JEV, we can postulate processing mechanisms of a polyprotein translated from single long open reading frame of the genome and mechanisms of construction of antigenic structures of structural proteins with biologically active forms after these proteins are translated. The results of comparative analysis of amino acid sequences among flaviviruses and epitope analysis on the E proteins which are the most important antigens for protective immunity suggest that the E protein of flaviviruses may have a similar structure closely related to each other. PrM and E proteins which had predictable signal sequences upstream on the N terminals were expressed with antigenically active form and molecular size the same as the authentic ones by the recombinant viruses. However, the recombinant viruses which had no such signal sequence expressed unprocessed proteins with antigenically denatured forms. These results suggest that normal proteolytic processing is needed to construct biologically active structures of JEV structural proteins. The E proteins which were expressed by the recombinant viruses as antigenically active form could elicit nutralizing and HI antibodies in animals and protective immunity in mice. The recombinant vaccinia viruses which express the E protein could induce strong immunologic memory against the E protein in mice. These results indicate that the development of a new type of vaccine against JEV will become possible in future.