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Objective To clone and express Schistosoma j aponicum cyclophilin B (SjCyPB) gene in E.coli,and to identify and analyze the immunity of recombinant proteins.Methods A pair of specific primers was designed according to GenBank of Schistosoma japonicum sequence.SjCyPB gene was amplify by PCR and then connected to pET28 vector.The recombinant plasmid pET28a (+)-SjCyPB was constructed and transformed into E.coli BL21 cell line,the recombinant plasmid was identified by double enzyme digestion and sequence analysis.After induced by isopropyl-B-D-thiogalaetoside (IPTG),the expressed recombinant proteinwas purified by affinity-chromatography,and then verified by Western blotting.Rats were immunized recombinant SjCyPB,andthe SjCyPB-specific IgG was detected by ELISA.Results SjCyPB gene was successfully inserted into pET28a(-) vecter which identified by double enzyme digestion and sequence analysis.Recombinant SjCyPB protein was highly expressed in E.coli.The Western Blotting analysis confirmed that the recombinant protein could specifically combine to S.japonicum-infected rabbit serum.Using recombinant protein to immunize rats,the SjCyPB-specific IgG antibody titer was 1 ∶ 51 200 detected by ELISA.Conclusion The recombinant SjCyPB is successfully constructed,and recombinant SjCyPB has immunogenicity and antigenicity.
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Objective In order to assess the value of Echinoccocus granulosus cyclophilin A (EgypA) in immune diagnosis,this novel gene was cloned and expressed.Methods By screening the EST library,the coding region of EgCypA was identified,and the PCR primers were designed based on this sequence.Bioinformatic tools were used to deduce the amino acid sequence of EgCypA and analyzed its biological characteristics.EgCypA was amplified from E.granulosus cDNA library by using PCR.Then,it was cloned into the prokaryotic expression vector pET28a and transformed into E.coli BL21.The recombinant protein was expressed in E.coli BL21 after IPTG induction.The immunogenicity of EgCypA was evaluated by Western blot using the Echinoccocus granulosus and other parasites infected animals' sera.Results Results of SDS-PAGE electrophoresis show that the recombinant BL21 expressed 18 400-25 000 protein,which was identical with the molecular weight calculated by bioinformatic analysis.Western blot shows that the recombinant protein only reacted with its immune serum and E.granulosus cystic fluid immune serum,and EgCypA immune serum could react with the excretion and secretion antigen from E.granulosus protoscolexes,and no cross-reaction between EgCypA and sera from other parasites infected animals.Conclusions Cloning and expression of EgCypA are successful.EgCypA has good immunologic activity and could be a candidate molecular for immune diagnosis of echinococcosis in early stage.
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Objective To observe the histopathologic injury of small intestine and intestinal permeability in chronic renal failure (CRF) rats. Methods Twenty male Sprague-Dawley rats were randomly assigned to CRF group (n=10) and control group (n=10). 5/6 nephrectomy was used to establish CRF rats, while sham operation for control. Blood biochemistry was regularly monitored until CRF model was successfully established. The model rats were fed with lactulose (L) and mannitol (M) through intragastric administration. Urine was collected after 6 hours, and the concentration of lactulose and mannitol in urine was measured using high pressure liquid chromatograph with refractive index detector (HPLC-RID), and the ratio of urinary excretion of L/M was calculated to evaluate intestinal permeability. Small intestinal mucosa were stained by hematoxylin-eosin (HE) and observed with light microscope (villus height, thickness of muscle layer and villus count), histological damage score was used to evaluate intestinal injury. Results The L/M ratio of CRF group was higher than that of control group (1.75±0.11 vs 1.20±0.06, P<0.01). The small intestinal mucosal villus height and thickness of muscle layer in CRF group were higher (P<0.01), and the number of villi was lower compared to control group (P<0.01). The score of histopathologic intestine damage of CRF group was higher than that of control group (1.00±0.71 vs 0, P<0.01). Conclusion The intestinal permeability of CRF rats is increased with varying degrees of intestinal damage.
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Objective To understand the structures and functions of enterovirus 71 (EV71)VP1 gene and its encoded protein using bioinformatics method, so as to direct studies of its biological function. Methods VP1 gene and its encoded protein of EV71 2008-GZCH07 strain and other representative EV71 strains were analyzed by online analysis at bioinformatics websites and software packages. Multi-sequence homological alignment and phylogenetic analysis were performed.Physicochemical characteristics, secondary structure, homology modeling of tertiary structure,enzymological characteristics, antigenic epitope of VP1 gene encoded protein were predicted. Results The homology of EV71 2008-GZCH07 strain was highest (97% and 98%) with ZJ001 strain, and lowest with human coxsackievirus A16. The homology of EV71 2008-GZCH07 strain and EV71 types A,B,C was 86%-98%. Phylogenetic analysis demonstrated that 2008-GZCH07 stain was close to ZJ001 and BJ08-Z025-5 stains, which belonged to C4 subtype. In VP1 encoded proteins of EV71 types A,B,C, the relationship between 2008-GZCH07 and EV71-B, EV71-C was closer than EV71-A.The whole length of VP1 gene was 510 bp, with open reading frame (ORF) located at 116-510 bp region,and it encoded 132 amino acids with isoelectric point of 4.39.The protein was rich of a-helix and random coilon without transmembrane regions, and contained 5 high hydrophobic regions and belonged to extracellular protein. The homology modeling of tertiary structure showed that the region was on the surface of protein and formed a binding loop. There was 5 antigen epitopes. And 7 key catalytic sites were located at or close to the loop. Conclusions EV71-VP1 encoded protein contains many phosphorylation sites, with many biological function sites and antigenic epitope regions, which might be a potential target antigen for immunodiagnosis, anti-schistosome drug and vaccine development, and would be basis of further study of diagnosis, treatment and prevention of EV71 infection.
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Objective To analyze the immunological characteristics of Trichinella spiralis secretory antigen P53 and to evaluate its value in diagnosis of trichinellosis. Methods An open read frame of secretory antigen P53 was cloned from Trichinella spiralis by reverse transcriptasepolymerase chain reaction (RT-PCR) and then sequenced. Bioinformatics analysis was performed to search for its homologues in other helminths and predict its potential linear B cell epitopes and T cell epitopes. The sequence coding mature peptide was inserted into prokaryotic expression vector pET28a(+) and the purified recombinant product was identified by Western blot using serum samples of patients infected with Trichinella spiralis or other helminth. Results Bioinformaties analysis results showed that there was no P53 homologue in other helminths, which indicated that there were many linear B cell epitopes and T cell epitopes in TsP53. The recombinant P53 antigen only reacted with the serum samples of patients infected with Trichinella spiralis without any cross-reaction with the serum of patients infected with other helminths. Conclusion P53 has strong immunogenicity and immunoreactivity, which may be a promising candidate for developing Trichinella spiralis specific diagnostic method.
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The structure and properties about encoding protein of lactate dehydrogenase A from Taenia solium(Ts LDH-A)were analyzed and predicted by bioinformatics in this study.The immunological characteristics of this novel gene were also analyzed by cloning and expressing.The full-length cDNA encoding Ts LDH-A was identified from the cDNA plasmid library by blastx and rpsblast programs provided by NCBI.The physico-chemical properties and structures of Ts LDH-A were analyzed by tools provided by ExPASy.And the B cell epitopes of Ts LDH-A were predicted by the B Cell Epitope Prediction Tools provided by IEDB Analysis Resource.The PCR amplified coding region of Ts LDH-A was cloned into the prokaryotic expression vector pET-28a (+) and expressed in E.coli BL21 with IPTG induction.The immunogenicity of the purified recombinant protein was analyzed by Western Blotting.It was demonstrated that the amino acid sequence of Ts LDH-A had identity with that of LDH-A from other specie and there was a conserved LDH domain in the deduced amino acid sequence.The full-length cDNA sequence encoding Ts LDH-A included a complete open reading frame(ORF)of 1332 bp and coded to a putative protein with 331 amino acids.The molecular weight of Ts LDH-A was predicted to be 35461.1 Da and the coding protein was demonstrated to contain 3 trans-membrane regions and 4 main B cell epitopes.The active site of L-lactate dehydrogenase located at the epitope aa190-199.The 3 key residues in the catalytic site of enzyme were conserved in different species and located near to each other in spatial position.PCR,double enzyme restriction and DNA sequencing were used to identify pET28a (+)-Ts LDH-A.The recombinant protein could react with the rat's sera as well as the sera from the patients and the swine infected Taenia solium.It is clear that the full-length cDNA sequence encoding Ts LDH-A can be screened from the cDNA library of adult Taenia solium by bioinformatics analysis and can be used to investigate the structure and properties about gene and encoding protein of Ts LDH-A as well as the immunological activities of gene expression in the prokaryotic system.
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To analyze the structural characteristics of the Rap2B gene from Clonorchis sinensis by bioinformatics and to clone and express this gene through genetic engineering methods in order to obtain the corresponding recombinant protein.The structural and functional characteristics of the Rap2B protein were analyzed by using the related bioinformatic softwares. Using the full-length cDNA plasmid clone (Noc009e03) as template , the coding region of Rap2B gene sequence was amplified with PCR and cloned into the prokaryotic expression vector pET-28a(+) and then expressed in E.coli BL21 through IPIG induction. The recombinant protein expressed was purified by Ni-IDA affinity chromatography and detected by SDS-PAGE and Western blotting. It was demonstrated that the size of this gene was 847 bp in length, encoding 141 amino acids and its theoretical molecular weight was 15851.1 daltons. As demonstrated by PCR, double enzyme digestion and DNA sequencing, the recombinant expression plasmid pET-28a(+)-Rap2B was successively constructed and the Rap2B-like gene was highly expressed in E.coli BL21. The recombinant protein was obtained through purification with His affinity chromatography and could react specifically with the serum of rats infected with C.sinensis. Through these investigations, the Rap2B protein may be predicted as a member of the Ras oncogene family protein and is potential in the carcinogenic process of C.sinensis.
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Objective To understand the primary structure and potential antigenic epitopes of antigen Pf332(Ag332) of P.falciparum iso late FCC1/HN.Methods Based on the published Pf332 gene sequence , nine pairs of primers were designed for the PCR amplification of the Pf332 gen e fragments from genomic DNA of P.falciparum isolate FCC1/HN. The amplified gene fragments were subcloned into pMD-18T vectors and sequenced. The sequences were aligned using DNAstar software to obtain the full-length sequence of the gene Pf332. The primary structure and sequence homology of Ag332 were analyzed by SAPS, Tmpred, SingalP and Blastn programs. Three fragments, R0, R1 and R2, cor responding to nt#9595-10083, nt#10339-10767 and nt#10855-11247 of Pf332 gene were subcloned into the eukaryotic expression vector pcDNA3-S separately. The Balb/c mice were immunized with pcDNA3-S-R0, pcDNA3-S-R1 and pcDNA3- S-R2 separately, and the expressions of the recombinant proteins were detected by immunohistochemistry assay. The protective immune responses elicited by DNA I mmunization were analyzed by ELISA and parasite growth inhibition tests in vitro .Results Nine Pf332 gene fragments were specifically amplif ied, subcloned into pMD-18T vectors and sequenced. Pf332 gene of the P.falci parum isolate FCC1/HN was 16,377 bp in length, encoding a protein of 5,458 ami no acids, about 615.28kDa. The Ag332 contains 17 regions of highly degenerated Glu-rich repeats, with 30.18% Glu in total amino acids of Ag332. Ag332 of P.falciparum isolate FCC1/HN and 3D7 exhibited 94.55 % homology in amino acid residues. The results of immunohischemistry assay showed that R0, R1 and R2 were expressed in mice muscle tissue. The amount of IgG antibody of the groups immu nized with pcDNA3-S-R0, pcDNA3-S-R1 and pcDNA3-S-R2 were higher than those of blank and pcDNA3 groups (P＜0.05). The result of parasite growth inhibition test showed that the immunized sera at 1∶5 dilution of groups of pcDNA3-S-R0, pcDNA3-S-R1 and pcDNA3-S-R2 had an incomplete inhibitor y effect on P.falciparum growth. Conclusion The antigen Pf332 is an large protein containing highly degenerated Glu-rich repeats. Pf332 gene fragments, R1 and R2 encoding potent antigenic epitope repeats.
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Objective To obtain the recombinant IgE-dependent histamine-releasing factors of Schistosoma japonicum and Clonorchis sinensis (rSjHRF and rCsHRF) and to study the effect of recombinant HRFs to induce histamine release from sensitized rat mast cells. Methods The complete coding regions of SjHRF and CsHRF were cloned separately, and the recombinant plasmids were respectively transformed and expressed in BL21 cells. The soluble recom-binant rSjHRF and rCsHRF were purified. Aliquots of the mast cells obtained from the lungs of OVA-immunized rats were separately incubated with rSjHRF and rCsHRF and the released histamine was measured by the OPT spectrofluorometric procedure. The dose-dependent curves and the kinetics of histamine release induced by rSjHRF and rCsHRF were prepared. Results The recombinant plasmids pET-30-rSjHRF and pET-30-rCsHRF were constructed successfully and the purified soluble recombinant proteins rSjHRF and rCsHRF were obtained by affinity chromatography. rSjHRF and rCsHRF induced histamine release from sensitized mast cells in a dose-dependent manner. At the concentration of 150 mg/L, the average rate of histamine release from sensitized mast cells induced by rSjHRF and rCsHRF were 49.78% and 32.63%, respectively. Histamine release increased with prolonged reaction time and the maximal release occurred at 35min. Conclusion The recombinant parasite-originated IgE-dependent HRFs show an effect of inducing histamine release from sensitized mast cells, suggesting that this protein would play a role in type I hypersensitivity in hosts with parasitic infections.
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Objective To establish and maintain the life cycle of Clonorchis sinensis in laboratory.Methods Adult worms and eggs of Clonorchis sinensis were collected from naturally infected cats.Eggs were ingested by freshwater snails in aquarium.When the cercariae were released from infected snails, they invaded into freshwater fishes.From the 30th day on after the release of cercariae, the infection rate and metacercariae density in freshwater fishes were determined.Results After 95 days the infected snails began shedding cercariae in a temperature range of 24.3-37.2 ℃, and no cercariae were found under 20 ℃.The infection rate in the snails Parafossarulus striatulus and Alocinma longicornis was 12.5% and 18.0%, respectively.Metacercariae were found in fish at 30 days after cercariae infection, and matured metacercariae were detected in 45 days.The number of metacercariae per gram of fish meat in Pseudorasbora parva, Ctenopharyngodon idellus, Rhodeus sinensis, Hypophthalmichthys nobilis, Cirrhinus molitorella, Carassius auratus, Cyprinus carpio and Oreochromis niloticus was 1 792, 16, 8, 6, 5, 4, 4, and 2, respectively.Rats and cats were fed with metacercariae from fish to receive adult worms.Conclusion Life cycle of Clonorchis sinensis has been established and maintained in the laboratory.
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Objective To recognize and identify the arginase(ARG)gene of Schistosoma japonicum(Sj),and to study its protection potential as a vaccine.Methods The 5'-end of the ARG gene from the Sj cercariae cDNA library was amplified by nested-PCR and the sequence was identified by bioinformatics.The complete coding sequence(CDS)was cloned into pET30a(+)vector,and a recombinant SjARG protein(rSjARG)was expressed,purified and used to raise antibodies.ARG's activity as an enzyme was tested by ornithine-ninhydrin reaction.Western blotting was used to compare the immunologic characteristics of rSjARG with that of the native one in Sj adult worm.Indirect immunofluorescence assay was used to immunolocalize it.For evaluating the protection potential of rSjARG,mice were immunized by the recombinant protein and challenged by cercariae of S.japonicum.Results The CDS length of the SjARG novel gene was identified as 1095bp.rSjARG showed enzyme activity and the same immunologic characteristics with the native arginase in adult worm.SjARG located in the genital organ and gut of both sexes.The worm reduction rate and egg reduction rate in rSjARG group were 55.8% and 48.8% respectively,higher than that of the rSj26GST group(28.6% and 6.89% respectively).Conclusion SjARG gene was identified,which shows a higher protection than the Sj26GST.