Objective To establish a mouse model of genital human papillomavirus (HPV) pseudovirion (PsV) transmission and evaluate the protective potency of HPV16 VLP vaccine.Methods HPV16 PsV with the encapsidated luciferase expressing plasmid Luc were generated from 293FT cells and purified by size-exclusion chromatography.The endpoint titers of HPV16 PsV-Luc were determined on 293FT cells, denoted as TRLU/mL.For in vivo genital challenge, mice were synchronized in a diestrus-like status by a subcutaneous injection with 0.1 μg β-estradiol and then with 3mg DepoProvera after 24 hours.Six hours prior to HPV16 PsV-Luc challenge, deeply anesthetized mice were intravaginally pretreated with 50 μL of 4%nonoxynol-9 ( N-9 ).HPV16 PsV-Luc was thoroughly mixed with 20 μL solution containing 4%carboxymethylcellulose ( CMC ) and intravaginally instilled using a positive-displacement pipette.Forty-eight hours after PsV-Luc challenge, mice were anesthetized and D luciferin was intravaginally instilled.After 3 minites, bioluminescence was measured with a cryogenically cooled Xenogen IVIS camera system.Then,the murine genital challenge model was used to determine the potency that HPV16 VLP vaccine is efficient at preventing HPV infection.Results HPV16 PsV-Luc was generated and purified from 293FT cells.HPV16 PsV-Luc was verified to containe L1 and L2 protein by Western blot.HPV 16 PsV-Luc successfully infected vaginal epithelial cells of mouse and the murine genital challenge model was established.To achieve consistent bioluminescence, the minimal dose of HPV16 PsV-Luc was 1.7 ×104 TRLU.The protective potency of HPV16 VLP vaccine was shown using this murine model.Our data showed that immune serum with over neutralizing antibody titer of 256-fold was sufficient to confer protection against HPV PsV genital infection .Conclusion The murine genital challenge model of HPV16 was successfully established, and the model is used to evaluate the potency of HPV16 VLP vaccine against in vivo genital HPV16 PsV challenge.Our model will benefit for the investigation of HPV neutralization and the potency evaluation of the HPV vaccine .

Objective To quantitatively analyze the characteristics of a panel of murine anti-human papillomavirus(HPV)11 L1-derived virus-like particle( VLP ) monoclonal antibodies ( mAbs ) and establish the mAb-based methods for antigen quality analysis.Methods A panel of 22 murine anti-HPV11 mAbs were characterized in details with their isotype, and binding affinity, conformational sensitivity were examined quantitatively in the direct binding ELISA and Western blot.The hemagglutination inhibition activity of mAbs were identified using the hemagglutination inhibition assay and the pseudovirus ( PsV ) neutralization efficiency were examined quantitatively using the PsV-based neutralization assay.The type-specific, highly conformational sensitive and neutralizing mAbs were selected to be used in the sandwich ELISA assay.Results Based on the quantitative and semi-quantitative results, six type-specific, highly conformational sensitive and neutralizing mAbs (2A2, 4A1-3, 16G7, 14A6, 9C1 and 19C7) were identified.These mAbs, along with 10D6 were screened as the capture mAb or as the detection mAb in the sandwich ELISA.Conclusion The binding affinity, conformational sensitivity and neutralization efficiency of anti-HPV11 mAbs were characterized in details.A mAb-based sandwich ELISA assay (14A6:Ag:9C12-HRP) were developed, which could be used in the in vitro potency analysis of HPV11 VLP-based vaccine.

Persistant infection of high-risk human papillomavirus (HPV) is the primary cause leading to cervical cancer, which is ranked as second cancer threatening the health of women following breast cancer.Development of HPV vaccine is very important because there is no effective therapeutics for cervical cancer.Three currently licensed HPV vaccines based on major capsid protein L1 in the foreign market confered good safety and efficacy in clinical trials, but the current price is expensive due to high cost, which limits the wide application in developing countries.So far, the vaccines have not been launced in China market.Here, we review the progress and the current status of the HPV vaccine, which will attract the readers’ interest on the forthcoming emergence of HPV vaccine in China.

Objective To obtain monoclonal antibodies ( mAbs ) against neutrophil gelatinase-associated lipocalin ( NGAL ) and a chemiluminescense immune quantification assay based one paired mAbs.Methods Six-to-eight weeks old female BALB/c mice were immunized with the purified recombinant human NGAL antigen( rhNGAL) that was produced by the Escherichia coil expression system.The spleen was fused with hybridoma for screening anti-NGAL monoclonal antibodies by indirect ELISA.Western blot was implemented to identify the reactivity with native NGAL. Results The rhNGAL antigen was found to form disulfide cross-linked dimers and present excellent immunogenicity.The reaction titer of the immune serum of NGAL immunized mice was about 106.Thirty mAbs were screened by indirect ELISA, hereinto;the EC50 values of mAb23C12 and 38D10 were 0.034 g/mL, 0.022 g/mL respectively.The antibodies pair, 38D10/23C12-SAE labeled with AcridiniumEster(AE), were shown to work well in chemiluminescense immune response quantitative detection which was screened by NGAL standardand clinical urine samples.This detection can resolve positive and negative samples with a statistically significant difference (P<0.0001).And the correlation coefficient R2between NGAL quantitative results and that of the Abbott's NGAL chemiluminescence immune assay kit was greater than 0.97.The detection linear range was 10-1500 ng/mL, analytical sensitivity of the method was 0.63 ng/mL.Conclusion Highly purified rhNGAL antigen and specific anti-NGAL monoclonal antibodies are generated in this study.The detection capability of method is comparable with that of the international commercial kit.

Objective To search for the neutralizing epitopos on hepatitis E virus (HEV) capsid besides the known neutralizing epitope (aa459-606). Methods By analysis of several strains of monoclonal antibodies against HEV capsid and their recognized epitopes, the neutralizing activity of epitope (aa394-458) at N-terminus was compared with that of an immunodominant neutralizing epitope (an459-606). Re-suits The research showed a novel potential neutralizing epitope in aa423-437 of HEV ORF2 though detec-ting and comparing the characteristics of several antibodies and corresponding determinations. The epitope is a linear non-immunodominant epitope which is different from the other neutralizing epitope in aa459-606.And the amino acids sequence of this novel epitope is conservative. Conclusion ORF2 aa423-437 is a no-vel potential neutralizing leaner epitope of HEV. It is believed that the present work adds fundamental knowl-edge to our understanding of HEV capsid domain and contributes to the prevention and control of this dis-ease.

Objective To produce human papillomavirus type 6(HPV-6)virus-like particles with Escherichia coli expression system and study its immunogenicity.Methods HPV-6 L1 gene was inserted into pmkaryotic expression vector pTO-T7 and then expressed in Escherichia coli ER2566.The HPV-6 L1 protein was purified by ammonium sulfate precipitation,ion-exchange chromatography,and hydrophobic interaction chromatography.Then the purified HPV-6 L1 self-assembled into virus-like particle after removing 1,4dithiothreitol(DTr).The morphology of the virus-like particles was investigated with dynamic light scatter and transmission electron microscopy,and the immunogenicity was determined with in vitro pseudownons neutralization as8ay.Results HPV-6 L1 was expressed in soluble form in Escherichia coli.Following the removal of DTT,purified HPV-6 L1 protein could assemble into virus-like particles as 25 am in the radius.And the animal immunization test showed HPV-6 virus-like particles can elite hish titer neutralizing antibodies.Conclusion The bacterially expressed HPV-6 L1 VLP is highly immunogenieity and easy to produce.And it can be good candidate of HPV-6 vaccine.

Objective To establish an efficient baculovirus-insect cell expression system for the production of human immunodeficiency virus-1 ( HIV-1 ) envelope glycoprotein gp120 and to evaluate the physiochemical properties, antigenicity and immunogenicity of the recombinant protein. Methods The gene encoding HIV-1 NL4-3 gp120 was cloned into the downstream of pH promoter of the baculovirus transfer vec-tor pAcgp67B to construct the recombinant transfer vector pAc-gp120. Expression of the protein of interest was induced in baculovirus-infected High FiveTM insect cells. ELISA, analytical ultracentrifugation and size-exclusion chromatography were carried out to characterize physicochemical properties of the expressed gp120 protein. Immunogenicity of the recombinant gp120 protein was analyzed by HIV neutralization assay after im-munizing BALB/c mice with it. Results The recombinant HIV-1 gp120 protein was successfully obtained from the established insect cell expression system with a purity of more than 90％ and a mean yield of 13 mg/L in four batches. That recombinant HIV-1 gp120 protein was characterized by homogeneity in solution and possessed a good immunoreactivity to neutralizing antibodies and antisera against HIV. Immunogenicity analysis in BALB/c mice demonstrated that the recombinant gp120 protein could induce effective immune re-sponses against HIV-1 NL4-3. Conclusion A simple and scalable approach to obtain homogeneous and im-munogenic HIV-1 gp120 antigen is successfully established, which will promote further investigation of HIV vaccine candidates.

Antibodies, Monoclonal ; chemistry ; immunology ; Antigens, Viral ; chemistry ; genetics ; immunology ; Binding Sites ; Capsid Proteins ; chemistry ; genetics ; immunology ; Epitopes ; chemistry ; genetics ; immunology ; Escherichia coli ; genetics ; metabolism ; Gene Expression ; Hepatitis E ; immunology ; prevention & control ; virology ; Hepatitis E virus ; chemistry ; immunology ; Humans ; Molecular Docking Simulation ; Mutagenesis, Site-Directed ; Peptide Mapping ; Protein Binding ; Recombinant Proteins ; chemistry ; genetics ; immunology ; Viral Hepatitis Vaccines ; administration & dosage ; biosynthesis

Here, we presented a method to bacterially express the major structural protein L1 of Human Papillomavirus type 18 (HPV18) as soluble form. We found that the purified L1 could self-assemble to virus-like particles (VLPs). Further, we investigated the immunogenicity and the induced level of neutralizing antibody using these VLPs. First, the genome of HPV18 was cloned from a patient in Xiamen. It was used as template for PCR amplification of HPV18 L1 gene. The resultant DNA fragment was inserted into expression vector pTrxFus and expressed in Escherichia coli GI724. Second, L1 protein was purified by ammonium sulfate precipitation, ion-exchange chromatography and hydrophobic interaction chromatography; and the purified L1 was subjected to self-assembly to form VLPs with the removal of premixed reductant DTT. Finally, the size and morphology of these VLPs was investigated by Dynamic Light Scattering and Transmission Electronic Microscopy as 29.34 nm in hydrated radius and globular particles similar with native HPV18. The half effective dosage (ED50) and maximum level of neutralizing antibody elicitation were measured by vaccinations on mice, rabbit and goat using pseudovirus neutralization cell model. The results showed that the ED50 of HPV18 VLPs is 0.006 microg in mice, and the maximum titer of neutralizing antibody elicited in rabbit and goat is up to 10(7). As a conclusion, we can provide HPV18 VLPs with highly immunogenicity from prokaryote expression system, which may pave a new way for research and development of prophylactic vaccine for HPV18.
Animals ; Capsid Proteins ; biosynthesis ; genetics ; immunology ; Escherichia coli ; genetics ; metabolism ; Goats ; Human papillomavirus 18 ; immunology ; isolation & purification ; Mice ; Oncogene Proteins, Viral ; biosynthesis ; genetics ; immunology ; Rabbits ; Recombinant Proteins ; biosynthesis ; genetics ; immunology ; Virion ; genetics ; immunology

We produced high pathogenic avian influenza H5N1 haemagglutinin protein HA1 in recombinant Pichia pastoris in a 10 L fermentor, to establish a high-density cell fermentation method. We studied the effects of different factors such as culture temperature, induced temperature, methanol feeding methods, trace elements on the growth of Pichia pastoris, the yield and the biologic activity of recombinant HA1 protein. The culture temperature in pre-induced and induced stage were optimized at 25 degrees C to adapt cell growth and recombinant protein expression, and induced temperature at 25 degrees C also resulted in higher biologic activity of rHA1 than at 30 degrees C. The binding activity of rHA1 against a wide-spectrum neutralizing antibody was susceptible to the presence of any trace elements, although trace elements would essentially benefit for the cell fermentation. As a conclusion, the expression level of rHA1 produced with optimized fermentation process reached 120 mg/L, which was 10.5 times higher than the one produced in regular shaking flask. The resultant high-density cell fermentation can likely produce rHA1 of H5N1 in large scale.
Fermentation ; Hemagglutinins, Viral ; biosynthesis ; genetics ; Influenza A Virus, H5N1 Subtype ; genetics ; metabolism ; Pichia ; genetics ; metabolism ; Recombinant Proteins ; biosynthesis