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Objective To study the effects of MF59 in combination with heat-killed BCG ( hBCG) as adjuvant on the immunogenicity of Mycobacterium tuberculosis fusion protein PstS1-LEP.Methods BALB/c mice were divided into six groups from group 1 through group 6.They were immunized with PstS1-LEP+MF59 ( group 1 ) , PstS1-LEP+MF59/hBCG ( group 2 ) , PstS1-LEP+hBCG ( group 3 ) , MF59 ( group 4 ) , PstS1-LEP (group 5) and hBCG (group 6) for three times at intervals of two weeks , respectively.The mice were sac-rificed two weeks after the last immunization .The serum samples were collected for antibodies detection .The splenic lymphocytes and peritoneal macrophages were isolated and cultured with PstS 1-LEP.Indirect ELISA and sandwich ELISA were used to detect PstS 1-LEP-specific antibodies and cytokines in the supernatants of culture , respectively.Results The level of IFN-γ, IL-1β, IgG, IgG1 and IgG2a in group 1 were higher than those in groups 4, 5 and 6 (P<0.05).The level of IL-2 and IL-4 in group 1 were higher than those in groups 4 and 6 (P<0.05).The level of IFN-γ, IL-1β, IL-12, IgG, IgG1 and IgG2a in group 2 were higher than those in groups 4, 5 and 6 (P<0.05).The level of IL-2 was higher in group 2 than that in groups 4 and 6 (P<0.05). The level of IL-4 in group 3 was higher than that in group 4 ( P=0.05 ) .The level of IL-1βin group 3 were higher than that in groups 4 and 5 ( P<0.05 ) .The level of IgG was higher in group 3 than that in groups 4 and 6 (P<0.05).IgG1 level in group C was up-regulated in comparison with that in groups 4, 5 and 6 (P<0.05 ) .Conclusion hBCG as PstS1-LEP adjuvant induces a shift towards Th 2-type immune response , while MF59 induces Th1/Th2-type immune response.The combination of MF59 and hBCG inhibits the secretion of IL-4 by spleen lymphocytes , but enhances the secretion of IL-12 by macrophage .
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Objective To evaluate the potential value of IgG antibodies against recombinant PPE65 protein (rPPE65) of Mycobacterium tuberculosis in serodiagnosis of tuberculosis.Methods The gene encoding PPE65 protein of M.tuberculosis was cloned into the PET-28a vector and then expressed in Escherichia coli.The rPPE65 was purified with Ni-NTA affinity and ion exchange chromatography.After dialysis renaturation, the concentration of rPPE65 was determined using Lowry assay.ELISA was used to detect the levels of specific IgG against rPPE65 and recombinant PstS1 protein (rPstS1) in sera from 144 patients with pulmonary tuberculosis (PTB patients), 144 health controls, and 56 patients with non-tuberculosis pulmonary diseases.ROC curves were used to determine cut-off values with the results of IgG antibodies against rPPE65 and rPstS1 for 144 PTB patients and 97 controls with negative PPD skin test.The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of rPPE65 and the combination of rPPE65 and rPstS1 were counted.Results The PPE65 protein of M.tuberculosis was successfully expressed in E.coli. The purity and concentration of rPPE65 were 95% and 0.5 mg/ml, respectively.ROC analysis showed that the cut-off of ELISA using rPPE65 was 0.64.The sensitivity, specificity, PPV, NPV, and accuracy of rPPE65 were 34.7%(50/144), 93.5%(187/200), 79.4%(50/63), 66.5%(187/287), and 68.9%(237/344), respectively.The sensitivity, specificity, PPV, NPV, and accuracy of the combination of rPPE65 and rPstS1 were 59.0%, 91.0%, 82.5%, 75.5%, 77.6%, respectively.Conclusions The rPPE65 of M.tuberculosis appears to be a candidate antigen for serodiagnosis of tuberculosis.Detection of IgG antibodies against the combination of rPPE65 and rPstS1 can increase the sensitivity of serological test for tuberculosis.
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Objective To evaluate the frequency of pncA gene mutations in pyrazinamide-resistant (PZA-resistant)Mycobacterium tuberculosis(M.TB)isolates.Methods The isolates were tested for PZA susceptibility with absolute concentration method.The pncA gene was amplified and the products were cloned into T-vector,followed with sequencing.Results In all the 36 M.TB isolates,there were 25 PZA-resistant strains and 11 PZA-susceptible strains.Mutations of the pncA gene were found in 10 PZA-resistant isolates,four of which belonging to high PZA-resistant strains.The wild type pncA sequence was present in 3 PZA-susceptible strains, synonymous mutations of pncA gene were detected in two PZA-susceptible strains.Additionally,11 PZA-resistant strains and 2 PZA-susceptible ones showed putative regulatory mutations in the upsteam of pncA gene.Condusions The mutation of the pncA gene can cause the PZA resistance.However.there ale other drug resistance mechanism except this mutation.
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Objective To evaluate the value of PCR molecular beacon assay. In detecting mycobacterium tuberculosis in clinical specimens. Methods The sputum specimens of 142 patients with pulmonary tuberculosis and 42 patients with respiratory system diseases other than tuberculosis were tested by smears, cultures and PCR molecular beacon assays. Results The sensitivities of smears. cultures and molecular beacon assay in detecting mycobacterium tuberculosis in sputum specimens of patients with pulmonary tuberulosis were 35.2%,35.9% and 44. 4%, respectively. The specificity of molecular beacon assay in testing clinical specimens was 100%. Conclusion PCR molecular beacon assay is in a hermetially sealed simple tube, rapid and anticontaminative. This assay is higher in sensitivity and specifity,than smears and cultures is one of the effective mothods for diagnosis of tuberculosis.
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Objective To evaluate the prospects of recombinant 38000 protein of Mycobacterium tuberculosis in tuberculosis epidemic investigation and subunit vaccine preparation.Methods Physicochemical characteristics of recombinant 38000 protein was detected by P I, peptide-mapping analysis and circular dichroism,guinea pig skin test,MTT stain,and peripheral blood macrophage phagocytosis were used to investigate the roles of recombinant 38000 protein in the cell immunity.Results Recombinant 38000 protein was acidic protein,its P I, was 4 67.The number of alkaline amino acid correspond with theoretic number;The secondary structure of recombinant 38000 protein was composed of ?-helix(32 6%),?-turn(31 6%) and random coil(35 8%) Recombinant 38000 protein could induce DTH in guinea pig sensitized by Mycobacterium tuberculosis Recombinant 38000 protein enhanced phagocytosis of macrophage in mice . PBMC from 30 8% healthy donors and 25% tuberculosis patients were stimulated by the recombinant 38000 protein.Conclusion Recombinant 38000 protein may be used as diagnostic reagent and as an candidate in development of subunit vaccine.
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Objective To compare expression of extracellular proteins of virulent H37Rv and attenuated H37Ra in order to search differential proteins,to provide a train of thought for studing M.TB toxicity further.Methods Extracellular proteins were extracted from H37Rv and H37Ra which were inoculated and cultured on Suton's medium for three weeks.The first dimensional electrophoresis was performed on immobilized pH gradient rod gels(pH 3～10).Then the proteins in the rod gels were separated using SDS-PAGE gels.The silver-stained gels were dried and scanned with image scanner.The 2D image analysis was performed with image Master 2D Elite 3 10.Results The most protein spots deriving from extracellular proteins of H37Rv and H37Ra strains were in acidic range.In the basic range(pI more than 9 0),the number of protein spots belong to extracellular proteins of H37Rv and H37Ra was few.Three protein spots belong to low molecular range in H37Rv strain.However,absent in H37Ra strain.Conclusions Two-dimensional gel electrophoresis is useful to separate protein in Mycobacterium tuberculosis.
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Using the prime b(special to M. tuberculosis) to amplify 21 mycobacterium and 13 nonmycobacterium, the products amplified were detected by agarose gel electrophoresis. The sensitivity was 50fg at annealing temperature 61℃,and only M. tuberculosis, M. gastri were amplified, those results showed: the clinical isolated mycobacterium can be differentiated and detected quickly and efficiently by using the prime b(using the prime a when necessary) to amplify 16S～23S rDNA spacer sequence of mycobacterium.