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OBJECTIVE@#To conduct eukaryotic expression of the leucine-rich repeat containing 15 (LRRC15), a differentially expressed protein in excretory secretory antigens of Taenia solium cysticercus, and predict its antigen epitope.@*METHODS@#The molecular weight, stability, amino acid sequence composition, isoelectric point and T lymphocyte epitope of the LRRC15 protein were predicted using the bioinformatics online softwares ExPASy-PortParam and Protean. The full-length splicing primers were designed using PCR-based accurate synthesis, and the LRRC15 gene was synthesized. The recombinant pcDNA3.4-LRRC15 plasmid was constructed and transfected into HEK293 cells to express the LRRC15 protein. In addition, the LRRC15 protein was characterized by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting.@*RESULTS@#The recombinant pcDNA3.4-LRRC15 plasmid was successfully constructed, which expressed the target LRRC15 protein with an approximately molecular weight of 70 kDa. Bioinformatics prediction with the ExPASy-PortParam software showed that LRRC15 was a hydrophilic protein, which was consisted of 644 amino acids and had a molecular weight of 69.89 kDa and an isoelectric point of 5.6. The molecular formula of the LRRC15 protein was C3073H4942N846O953S28 and had an instability coefficient is 50.3, indicating that LRRC15 was an instable protein. Bioinformatics prediction with the Protean software showed that the dominant T-cell antigen epitopes were located in 292 to 295, 353 to 361, 521 to 526 and 555 to 564 amino acids of the LRRC15 protein, and the T-cell antigen epitopes with a high hydrophilicity, good flexibility, high surface accessibility and high antigenicity index were found in 122 to 131, 216 to 233, 249 to 254, 333 to 343, 358 to 361, 368 to 372, 384 to 386, 407 to 412, 445 to 450, 469 to 481, 553 to 564, 588 to 594, 607 to 617 and 624 to 639 amino acids. Following transfection of the recombinant pcDNA3.4-LRRC15 plasmid into HEK293 cells, SDS-PAGE and Western blotting identified LRRC15 proteins in cell secretory culture media, cell lysis supernatants and sediments. The LRRC15-His fusion protein was purified from the cell culture medium, and SDS-PAGE identified a remarkable band at approximately 70 kDa, while Western blotting successfully recognized the band of the recombinant LRRC15 protein.@*CONCLUSIONS@#The eukaryotic expression and antigen epitope prediction of the LRRC15 protein in the excretory secretory antigens of T. solium cysticercus have been successfully performed, which provides insights into further understandings of its biological functions.
Subject(s)
Animals , Humans , Amino Acids , Antigens, Helminth/genetics , Cysticercus/genetics , Epitopes/genetics , Eukaryota , HEK293 Cells , Leucine-Rich Repeat Proteins , Membrane Proteins , Taenia solium/geneticsABSTRACT
Objective To evaluate the immune responses and protection against human metapneu-movirus ( hMPV) conveyed by influenza virus vectors carrying multiple epitope antigens of hMPV. Methods Two recombinant influenza viruses ( rFLU/hMPV/B and rFLU/hMPV/CTL+Th ) carrying hMPV multi-epitope gene segments in NS gene were generated by reverse genetic techniques of eight-plasmid system. BALB/c mice were immunized intranasally with rFLU/hMPV/B and rFLU/hMPV/CTL+Th twice at a two-week interval. Virus-specific antibody titers and splenocyte cytokines were detected two weeks after the boost immunization. Viral loads in lung tissues and turbinates were detected with digital PCR after the immunized mice were challenged with hMPV and influenza virus. Moreover, HE staining was used to observe lung inju-ries. Results Specific antibodies against both the influenza virus and hMPV were induced in mice immu-nized intranasally with rFLU/hMPV/B, while the influenza virus-specific antibody response and hMPV-spe-cific cytotoxic lymphocyte response ( significant IFN-γ secretion ) were detected in mice immunized with rFLU/hMPV/CTL+Th. Additionally, balanced Th1/Th2 responses were elicited by rFLU/hMPV/B and rFLU/hMPV/CTL+Th. Both rFLU/hMPV/B and rFLU/hMPV/CTL+Th conveyed effective protection against subsequent influenza virus and hMPV challenges with significantly alleviated histopathological dama-ges and reduced viral loads. Conclusions Both rFLU/hMPV/B and rFLU/hMPV/CTL+Th can induce spe-cific humoral immune response against hMPV and/or the influenza virus. Moreover, rFLU/hMPV/CTL+Th can also elicit hMPV-specific CTL immune response. These two recombinant strains can also protect BALB/c mice from the challenges with hMPV and influenza virus, suggesting that they are promising vaccine candi-dates.
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Objective@#To evaluate the immune responses and protection against human metapneumovirus (hMPV) conveyed by influenza virus vectors carrying multiple epitope antigens of hMPV.@*Methods@#Two recombinant influenza viruses (rFLU/hMPV/B and rFLU/hMPV/CTL+ Th) carrying hMPV multi-epitope gene segments in NS gene were generated by reverse genetic techniques of eight-plasmid system. BALB/c mice were immunized intranasally with rFLU/hMPV/B and rFLU/hMPV/CTL+ Th twice at a two-week interval. Virus-specific antibody titers and splenocyte cytokines were detected two weeks after the boost immunization. Viral loads in lung tissues and turbinates were detected with digital PCR after the immunized mice were challenged with hMPV and influenza virus. Moreover, HE staining was used to observe lung injuries.@*Results@#Specific antibodies against both the influenza virus and hMPV were induced in mice immunized intranasally with rFLU/hMPV/B, while the influenza virus-specific antibody response and hMPV-specific cytotoxic lymphocyte response (significant IFN-γ secretion) were detected in mice immunized with rFLU/hMPV/CTL+ Th. Additionally, balanced Th1/Th2 responses were elicited by rFLU/hMPV/B and rFLU/hMPV/CTL+ Th. Both rFLU/hMPV/B and rFLU/hMPV/CTL+ Th conveyed effective protection against subsequent influenza virus and hMPV challenges with significantly alleviated histopathological damages and reduced viral loads.@*Conclusions@#Both rFLU/hMPV/B and rFLU/hMPV/CTL+ Th can induce specific humoral immune response against hMPV and/or the influenza virus. Moreover, rFLU/hMPV/CTL+ Th can also elicit hMPV-specific CTL immune response. These two recombinant strains can also protect BALB/c mice from the challenges with hMPV and influenza virus, suggesting that they are promising vaccine candidates.
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To establish a novel colloidal gold immunochromatography assay (GICA) for rapid, sensitive and accurate detection of Haemophilus influenzae infection by using the outer membrane protein P6 as detection target. First, the linear antigen epitope located in the extracellular domain of the P6 protein (GenBank accession number: AGH02799) was predicted by bioinformatics analysis. The region (62-75 aa of the protein) with strong antigen specificity was chosen and synthesized. Two rabbits were then immunized by the polypeptides (14 aa) for production of polyclonal antibodies. Then, the recombinant P6 proteins were also obtained to produce polyclonal antibodies. Finally, based on the two antibodies, a novel colloidal GICA for detection of Haemophilus influenzae infection was established and the specificity, sensitivity, repeatability and stability of this method were evaluated. At the same time, the method was tested in clinical simulation, and the plate culture method was used to verify its accuracy. The test strip for Haemophilus influenzae infection was successfully prepared. The detection limit of the test strip was as low as 1×105 CFU/mL and the whole process can be completed within 15 minutes. The strip specifically recognized Haemophilus influenzae and did not react with nine of other common respiratory pathogens such as Streptococcus pneumoniae, Moraxella catarrhalis, Mycoplasma pneumonia, and Legionella pneumophila. And the strips could be stored at 25 °C for at least 6 months without losing sensitivity or specificity. The coincidence rate between the results of 200 clinical samples and the plate culture method was 90.5%. Haemophilus influenzae protein P6, which possessed a high degree of surface antigen accessibility and antigencity, could be used as a marker for Haemophilus influenzae detection. The immunochromatographic colloidal gold test strip which bears the features of rapidity, convenience and sensitivity provides a unique tool for the on-site surveillance and diagnosis of Haemophilus influenzae infection in clinical test.
Subject(s)
Animals , Humans , Rabbits , Chromatography, Affinity , Diagnostic Tests, Routine , Reference Standards , Gold Colloid , Chemistry , Haemophilus Infections , Diagnosis , Haemophilus influenzae , Limit of Detection , Sensitivity and SpecificityABSTRACT
The bioinformatics software was used to predict the B cell and T cell epitopes of Toxoplasma gondii microneme 16 (TgMIC16) followed by epitopes display on the yeast of Saccharomyces cerevisiae.B and T cell epitopes of TgMIC16 were predicted by DNAStar and IEDB,and software of SYFPEITHI and BIMAS,respectively.According to the predicted results,the antigenic epitope region was expressed with pCTCON2/EBY100 display system.The expression protein was detected by indirect immunofluorescence (IFA) and flow cytometry.Results showed that there were potential B/T cell epitopes in TgMIC16 and concentrated in the aa343-625 region.The epitope region was successfully displayed on the surface of yeast cells,and the optimal induction time was 24 hours.The study would lay the foundation for the development and efficacy evaluation of the yeast carrier vaccine in the further research.
ABSTRACT
The bioinformatics software was used to predict the B cell and T cell epitopes of Toxoplasma gondii microneme 16 (TgMIC16) followed by epitopes display on the yeast of Saccharomyces cerevisiae.B and T cell epitopes of TgMIC16 were predicted by DNAStar and IEDB,and software of SYFPEITHI and BIMAS,respectively.According to the predicted results,the antigenic epitope region was expressed with pCTCON2/EBY100 display system.The expression protein was detected by indirect immunofluorescence (IFA) and flow cytometry.Results showed that there were potential B/T cell epitopes in TgMIC16 and concentrated in the aa343-625 region.The epitope region was successfully displayed on the surface of yeast cells,and the optimal induction time was 24 hours.The study would lay the foundation for the development and efficacy evaluation of the yeast carrier vaccine in the further research.
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To confirm the B cell epitope recognized by monoclonal antibody (MAb) 3G11 of bluetongue virus type 8 (BTV-8) VP2 protein prepared in our laboratory, antigen epitopes recognized by 3G11 were screened and identified by phage display technology. KLLAT sequence was found by sequencing of blue spot after four rounds panning and 283LL284 of common short peptide sequence was obtained after comparison to amino acid sequence of BTV-8 VP2 protein. The peptide sequences KLLAA, KALAT, KLAAT and KLLAT were synthesized and identified by indirect ELISA. KLLAA and KLLAT bound strongly with supernatant and as cites of 3G11 cells and reacted specifically with BTV-8 positive standard sera. Further sequence analysis showed that amino acid sequence 283LL284 was conserved among different serotypes of BTV-8 strains, and283LL284 was the key amino acids of antigen epitopes recognized by 3G11. This study laid the foundation to establish type 8 BTV specific immunological detection methods.
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Objective:To artificially design and express a recombinant protein named as ScFv-pLLO by fusing ScFv gene of Rituximab(C2B8)and dominant antigen epitopes from listeriolysin O(LLO),and studying its anti-tumor activity.Methods:VH and VL gene sequences of C2B8 against CD20 were acquired by searching United States Patent database,and ScFv sequence was constructed by linking VL and VH with a short peptide linker.Two CD4+T cell epitopes from LLO were selected and designed to splice ScFv sequence.The recombinant gene of ScFv-pLLO was cloned into prokaryotic expression vector and purified after induction.The capacity of ScFv-pLLO target-binding to B-cell lymphomas was evaluated by flow cytometry ( FCM ) and co-immunoprecipitation ( Co-IP ) .The effects of ScFv-pLLO on B-cell lymphomas proliferation and apoptosis were detected respectively.The immunogenicity of ScFv-pLLO was assessed by lymphocyte proliferation assay.Results: ScFv-pLLO was successfully expressed.It could bind to different B-cell lymphomas cell lines and obviously inhibit the growth of Raji cells as well as inducing apoptosis.Moreover,ScFv-pLLO was able to stimulate proliferation of spleen lymphocytes of immunized mice.Conclusion: The recombinant protein ScFv-pLLO can target-bind to B-cell lymphomas,and perform inhibitory effect and induce apoptosis on Raji cells that indicate ScFv-pLLO retain the capacity of ScFv derived from monoclonal antibody against CD20.Besides, ScFv-pLLO can induce immune response.This study provides a basis for further research about the role of ScFv-pLLO on simulating tumor cell antigens as well as being tumor vaccine adjuvant.
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Objective:To observe inhibitory effrects of DNA vaccine co-expressing CEA tandem repeat epitopes and FL on cancer cells in mice.Methods:The encoding sequences for CEA tandem repeats and FL were inserted into plasmid pcDNA3.0 using gene recombinant technique.BALB/c mice were immunized intramuscularly with the co-expressing DNA vaccine.The survival time and tumor size were measured and specific CTL cytotoxicity was detected by ~(125)I-UdR release method.Results:Compared with that of the control,the survival time was prolonged (P＜0.01)and the tumors were significantly inhibited in the mice immunized with the vaccine peDNA-triCEA_(625-667)-sFL(P＜0.01).The splenic cells from mice immunized with the vaccine pcDNA-triCEA_(625-667)-sFL induced strongly cytotoxicity against tumor cells H22-CEA ~+(P＜0.01).Conclusion:The recombinant DNA vaccine co-expressing pcDNA-triCEA_(625-667)-sFL can suppress the growth of tumor expressing CEA in mice and enhance CTL response against CEA antigen.
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Based on the gene sequence of AIV matrix protein 2(M2) and two cytotoxic T-lymphocyte epitopes derived from nucleoprotein,the prokaryotic expression vector pET-3M2e-NP1-NP2 was constructed.The target gene was expressed in the solvable form in BL21(DE3) when induced with 1.0 mmol/L IPTG and Western blot analysis showed that the expression product had good immunogencity.Purified fusion protein was mixed with various amount of adjuvant,including Freund's,Vash oil and chitosan,and then immunized 20-day-old chicken by intramuscular injection and boosted 3weeks later.Blood samples were collected weekly following the primary vaccination.The anti-M2e antibody was detected with ELISA method with the synthesized peptide as coated antigen;the neutralizing ability of anti-serum was evaluated on MDCK cell line and chick embryo,the CD4+ and CD8+ T lymphocyte amounts in peripheral blood of immunized chicken was measured by flow cytometry.Results showed that the fusion protein can induce immunological reaction,and the antibody can bind with the viral M2 protein that expressed on the surface of MDCK cells.Flow cytometry result showed that CD4+ and CD8+ T lymphocyte in peripheral blood increased obviously following immunization(P
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Objective To synthesize and fusion express the predicted T-cell epitopes of Schistosoma japonicum, and analyze their immunogenicities. Methods The plus and minus oligo-nucleic acid strands of epitopes P7, P17, P18 were synthesized following their DNA sequence, respectively. The Nco I restriction enzyme sites were added to the 5′ end of epitope gene and the Xho I restriction enzyme sites were added to the 3′ end of epitope gene. The plus and minus strand of each epitope gene was annealed to form double strand DNA fragments. Then the double strand DNA fragments encoding epitope peptide were cloned into the site between Nco I and Xho I of plasmid pET32c(+) to construct recombinant plasmid which was transformed into E.coli DH5?. The recombinant plasmid containing P7, P17, P18 genes respectively was identified by PCR, restriction digestion and DNA sequencing, and then transformed into E.coli BL21 (DE3) for expressing the fusion protein. The fusion protein of peptide-thioredoxin(Trx) was expressed by inducing with IPTG and analyzed with SDS-PAGE. The fusion proteins were purified with Ni2+ column affinity chromatography. Meanwhile, the peptides P7, P17, P18 were synthesized artificially following their amino acid se-quence. By using the purified epitope peptide fusion proteins and synthesized epitope peptides, the splenic cells of C57BL/6J mice immunized with ultraviolet-attenuated cercaria of Schistosoma japonicum were stimulated respectively. The stimulation activity of fusion proteins and synthesized peptides were assayed by detecting the incorporation rate of 3 H-thymidine. Results The double strand DNA fragments of epitopes P7, P17, P18 were successfully cloned to form recombinant plasmids, all of which could express a 20 kDa fusion protein. Both the fusion protein and synthesized epitope peptides of P7 and P17 were able to stimulate the lymphocyte cells to proliferation effectively. Conclusion The peptide P7 and peptide P17 are testified as T-cell epitopes of Schistosoma japonicum.
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Objective To screen the mimic antigen epitopes of the triose phosphate isomerase of Schistosoma japonicum Chinese strain (SjC TPI) and investigate their immunogenicity. Methods The random phage peptide library (PH^D^ 12) was screened with the purified antibody(IgG) against SjC TPI to get the positive phage which contained the mimic antigen epitopes of SjC TPI, and the immuno characterization of the mimic antigen epitopes were investigated. Results Two mimic antigen epitopes (M1, M2) of SjC TPI were obtained. The immuno sera of mice (Kunming strain) against the positive phages could recognize both the SjC TPI and the protein of the positive phages. The DNA sequencing data showed no homology between the sequences of the deduced amino acid of the two mimic antigen peptides and the amino acid of SjC TPI. Conclusion The two mimic antigen epitopes of SjC TPI obtained are imitative epitopes of the configuration antigen of SjC TPI.
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Objective:To investigate the epitope and its immunogenicity of bFGF. Methods -.The phage disply 7 peptides library was screened with monoclonal antibody GE22 to bFGF, which neutralize the bioactivin'es of bFGF. Results: After three cycles screening, the isolated phage clones with GF22 epitopes specifically inhibited bFGF binding to GF22.Sequence analysis showd that the epitopes shared a highly consensus spequence( Leu-Pro-Pro/Leu-Gly-His-Phe/He-Lys) and PPGHFK sequence was located at aino acids 22-27 (PPGHFK) within bFGF (155aa) molecule.Phage clones with the epitopes could highly induce imuno-response in mice,eapically with the sequence LPLGHK was 3 times higher than original sequence. Conclusion:Trie sequence LPLGHK may be a valuable vaccine in future studies of bFGF.