Serological assay to detect human antibodies against monkey poxvirus / 中华实验和临床病毒学杂志

Objective@#To establish a method for detection of human antibodies against monkeypox virus.@*Mothds@#The enzyme linked immunosorbent assay (ELISA) plates were coasted with two monkeypox virus peptides from B21R protein, to establish an indirect ELISA for detecting monkeypox virus IgG antibody. The healthy individuals serum samples, monkeypox virus infected patient serum samples and other virus infected patient sera samples were applied to evaluate specificity of the peptides antigen. The reaction conditions were optimized.@*Results@#Synthesized two peptides from monkeypox virus BR21R protein did not cross react obviously with healthy person serum and other virus infected serum. It was shown that the reaction condition was best with sera dilution at 1∶50 when two combined peptides were coated at 100 ng /well, and second-antibody was diluted at 1∶20 000. At this condition the cut off value of IgG antibody in serum samples for ELISA were A450 reading of 0.393. The detected results of two serum samples collected from the monkeypox patient in Sierra Leone were strongly positive, the titers of IgG antibody in two sera were both 1∶6 400.@*Conclusions@#The indirect ELISA for detection of monkeypox virus infection was established preliminarily which provided useful tools for epidemiological study and diagnosis.

Combined immunization with human papillomavirus type 18 fusion protein and recombinant vaccinia virus in mice / 中华实验和临床病毒学杂志

Objective@#To investigate the cellular and humoral immune responses induced by combined immunization with the fusion protein of human papillomavirus type 18 (HPV18) and the recombinant vaccinia virus.@*Methods@#Purified HPV18L231-600E7E6 fusion protein, expressed by prokaryotic expression system, were immunized in combination with the recombinant vaccinia virus vaccine expressing HPV18E7E6 fusion protein (rVV18E7E6) by using various prime-boost regiments in C57BL/6 mice. Cellular and humoral immune responses were analyzed by enzyme-linked immunospot assay (ELISPOT), enzyme-linked immunosorbent assay (ELISA), and pseudovirus neutralization assay.@*Results@#Higher levels of cellular immune responses were induced in mice primed with the HPV18L231-600E7E6 fusion protein/adjuvant CpG and boosted with the recombinant vaccinia virus rVV18E7E6, than in other immunized mice. Higher binding antibody level was induced, and low level neutralizing antibody against pseudovirus was detected simultaneously.@*Conclusions@#Priming with HPV18L231-600E7E6 fusion protein/CpG and boosting with the recombinant vaccinia virus rVV18E7E6 could induce higher cellular and humoral immune response in immunized mice, which might be taken as vaccine candidate for treatment of HPV18 chronic infection and postoperative adjuvant treatment for cervical cancer.

Preliminary exploration of replication-defective mechanism of highly attenuated NTV strain of vaccinia virus Tiantan / 中华实验和临床病毒学杂志

Objective@#To detect the expression level of early and late protein of vaccinia virus and to preliminarily explore replication-defective mechanism of highly attenuated NTV strain of vaccinia virus Tiantan.@*Methods@#We constructed prokaryotic expression vector, expressed and purified homologous early protein E3 and late protein A27 closely related to replication and prepared mouse polyclonal antiserum by immunizing mice with homologous proteins. Early and late protein expression levels of NTV were detected.@*Results@#We have expressed and purified vaccinia virus proteins respectively in E. coli expression system and prepared homologous mouse polyclonal antiserum. Early protein E3 and late protein A27 could be highly efficient expression in NTV infected non-permissive Hela cells, while expression of late protein F17 was blocked detected by Western blot.@*Conclusions@#The expression limitation of late protein F17 may be an explanation for the replication-defective mechanism of NTV.

Preparation and characteristic analysis of six influenza A (H7N9) pseudovirus derived from different districts of China / 中华实验和临床病毒学杂志

Objective@#To prepare strains of influenza A (H7N9) pseudovirus derived from different districts of China for vaccine efficacy evaluation.@*Methods@#Phylogenetic tree was built based on hemagglutinin (HA) amino acid sequence analyses from 29 influenza A (H7N9) virus strains and 6 influenza A (H7N9) virus strains with HA determinants variation were selected. 293FT cells were co-transfected with plasmid pNL4-3-Luc.R-E-, pVRC-HA and pVRC-NA with codon-optimized hemagglutinin (HA) and neuraminidase (NA) derived from the six influenza A (H7N9) virus strains, respectively. Transmission electron microscopy assay and Western blot analysis were performed to demonstrate morphology and specificity of these particles, luciferase activity assay and hemagglutinin titers detection were used to determine their infectivity and hemagglutinin activity. And finally, pseudovirus-based neutralization assays were evaluated with HA immunized mice serum.@*Results@#Six influenza A (H7N9) peseudovirus particles derived from different districts of China were selected and prepared. All of the particles bearing HA and NA were characterized with classic influenza virus morphology, with TCID50 titer ranged from 104TCID50/50 μl to 105TCID50/50 μl and with hemagglutinin activity ranged from 64 to 512. Neutralization efficacies on influenza A/Shanghai/1/2013(H7N9) HA vaccine serum against 100TCID50 dose of these pseudovirus particles indicated their potential application in the vaccine cross-protective evaluation in future.@*Conclusions@#Six influenza A (H7N9) pseudovirus derived from different districts of China with potential antigenic variation on HA were constructed successfully, established foundation for their further application in vaccine cross-reactive efficacy evaluation.

Research progress in monkeypox virus detection / 中华实验和临床病毒学杂志

Monkeypox is a zoonotic disease caused by monkeypox virus. It is similar to human smallpox, although typically much less serious and limited to human-to-human transmission. Smallpox no longer occurs following its worldwide eradication in 1980, whereas monkeypox still occurs sporadically in parts of Africa. To respond to the outbreak of monkeypox correctly, we need to rely on effective method of virus detection. This review presents the development in monkeypox virus detection method in recent years to provide reference for the situation of potential virus spreading into our country and for preventing and acting correctly against bioterrorism.

Generation and characterization of specific monoclonal antibodies against monkeypox virus / 中华实验和临床病毒学杂志

Objective@#To generate monkeypox virus specific monoclonal antibodies for further establishing monkeypox virus immunofluorescence assay.@*Methods@#Monkeypox virus A29 protein, vaccinia ortholog A27 protein and cowpox ortholog 162 protein were expressed in E. coli BL21 to screen antibodies. Synthetic monkeypox virus A2917 ~ 49 polypeptide was used to immune BALB/c mice. Monkeypox virus monoclonal antibodies were generated through fusion, cloning and screening techniques. Indirect ELISA was performed to test antibodies specificity and subtype.@*Results@#A29, A27 and 162 proteins were highly expressed in E. coli and detected by Western blot. The three his-tagged proteins were purified using His-Bind affinity chromatography column. The purity of the proteins was all more than 90%. And 8 strains monkeypox virus specific monoclonal antibodies were screened by the three purified proteins. Two mAbs of 8 were IgG3 subtype and the rest were IgG1 subtype.@*Conclusions@#Eight strains of monkeypox virus specific monoclonal antibodies were generated, they can be used to further establish monkeypox virus immune immunofluorescence assay.

Optimized expression, preparation of human papillomavirus 16 L2E7 fusion protein and its inhibitory effect on tumor growth in mice / 生物工程学报

HPV16 L2E7 is a fusion protein used for therapeutical vaccine targeting HPV virus. To increase its expression in Escherichia coli, we optimized the codon usage of HPV16 l2e7 gene based on its codon usage bias. The optimized gene of HPV16 sl2e7 was cloned into three different vectors: pGEX-5X-1, pQE30, ET41a, and expressed in JM109, JM109 (DE3) and BL21 (DE3) lines separately. A high expression line was selected with pET41a vector in BL21 (DE3) cells. After optimization of the growth condition, including inoculation amount, IPTG concentration, induction time and temperature, the expression level of HPV16 L2E7 was increased from less than 10% to about 28% of total protein. HPV16 L2E7 protein was then purified from 15 L culture by means of SP Sepharose Fast Flow, Q Sepharose Fast Flow and Superdex 200 pg. After renaturing, HPV16 L2E7 protein with ≥ 95% purity was achieved, which was confirmed via SDS-PAGE gel and Western blotting. The combined use of purified HPV16 L2E7 and CpG helper has shown clear inhibition of tumor growth in mice injected with tumor cells, with six out of eight mice shown no sign of tumor. This study lays a solid foundation for a new pipeline of large-scale vaccine production.

Immunogenicity and antitumor efficacy of the recombinant adenovirus expressing E7 and E6 fussion proteins of HPV type 16 in mice / 中华微生物学和免疫学杂志

ObjectiveTo construct one recombinant adenovirus AdE7E6 expressing HPV16 E6 and E7 fusion protein as candidate for HPV16 therapeutic vaccine.MethodsThe codon-optimized E6 and E7 gene,were fused to create one open reading frame,then inserted into adenovirus vector pCD316.A strain of recombinant adenovirus was constructed through homologous recombinant in 293 cells,and identified by PCR and Western blot.Finally,it was employed to study it's immunogenicity and the activity of the tumor growth regression.ResultsThe PCR result showed that E6E7 fusion gene had been integrated in recombinant Ad5 DNA.Western blot test confirmed that the E6E7 fusion protein was highly expressed in 293 cells infected with Ad5E7E6 recombinant adenovirus.The recombinant adenovirus elicited significant E7 specific CD8+ T lymphocyte response in vaccinated mice.These responses could completely prevent the TG-1 tumor cell bearing mice treated with AdE7E6 from developing into tumor.ConclusionThese results suggested that rAd5E7E6 could be a potent vaccine candidate for the treatment of HPV16-associated tumors and their precancerous transformations.

Construction of recombinant vaccinia virus co-expressing mutant E6 plus E7 proteins and detection of its immunogenicity and antitumor response / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To generate a candidate HPV16 vaccine for experimental and therapeutical use for cervical cancer.</p><p><b>METHODS</b>The mutants of HPV16 early E6 and E7 genes were inserted into a vaccinia virus expression vector. A strain of recombinant vaccinia virus was constructed through homologous recombination.</p><p><b>RESULTS</b>Showed that the mutant E6 and E7 genes were located at TK gene region of vaccinia virus Tiantan strain in a head to head orientation under the control of early/late promoters, H6 and 7.5K respectively. Studies in mice indicated that VmE6E7 could elicit specific antibodies against E6 and E7, and retarded or prevented tumor development in a proportion of C57 BL/6 mice challenged by syngeneic HPV16E6 and E7 transformed tumor cells.</p><p><b>CONCLUSIONS</b>The success in constructing VmE6E7 provides a basis for the further development of HPV16 therapeutic vaccine.</p>

Construction and identification of the replication-deficient recombinant vaccinia virus co-expressing HPV type 16 L1 and L2 proteins / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To generate an HPV16 prophylactic vaccine candidate for cervical cancer.</p><p><b>METHODS</b>HPV16 major capsid protein L1 gene and minor capsid protein L2 gene were amplified using PCR. These genes were mutated by PCR site-directed mutagenesis for removal of sequence motifs (TTTTTNT) which would cause transcription termination when expressed from a vaccinia virus early promoter, then inserted into a vaccinia virus expression vector. A strain replication-deficient recombinant vaccinia virus containing the mutant sequences was obtained through a homologous recombination and identified.</p><p><b>RESULTS</b>The nucleotide sequence remained the correct amino acid sequence of the L1 and L2 proteins after mutated. Full-length L1 and L2 proteins were generated in cells infected with the recombinant virus. The virus strain propagated at very low titer or could not reproduce in some kinds of cell derived from different human tissues.</p><p><b>CONCLUSIONS</b>The authors have generated a strain replication-deficient recombinant vaccinia virus expressing HPV16 L1 plus L2 proteins as an HPV16 prophylactic vaccine candidate for cervical cancer.</p>

Modification of HPV type 16 E6 and E7 genes, and analysis of stability and immunogenicity of the modified proteins / 中华实验和临床病毒学杂志

<p><b>BACKGROUND</b>To select the mutants of HPV type 16 E6 and E7 genes suitable for construction of vaccine for treatment of cervical cancer.</p><p><b>METHODS</b>E6 and E7 genes were modified by site-directed mutagenesis. Several recombinant vaccina viruses were constructed by inserting the E6 or E7 mutants into the genome of vaccina virus Tiantan strain and employed to study their antigenicity.</p><p><b>RESULTS</b>Western blot assay showed that the E6 ?mutant? with substitution of Gly for Leu at amino acid site 50 and E7 mutant with substitution of Gly for Cys-24 and Glu-26 had no effect on their stability and antigenicity, but change of the Cys at position 91 of E7 dramatically reduced its stability and antigencity. Conclusion The results confirmed that the Zinc-finger structure at the E7 C-terminal? plays an important role in the integrity and stability of E7 protein.</p>