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Objective To construct a eukaryotic expression plasmid of pcDNA 3.1-Ag85A-CD226, and to use it as DNA vaccine then further evaluate its immunogenicity through oral administration in a mouse model.Methods The CD226-PCR2.1-ToPo plasmid was used as the template to clone CD 226 gene by PCR.The CD226 gene was then inserted into pcDNA 3.1-Ag85A plasmid to construct the recombinant plas-mid of pcDNA3.1-Ag85A-CD226.After identified by restriction enzyme analysis and sequencing , the re-combinant plasmid was transfected into HEK 293 cells by using lipofection .The expression of Ag85A-CD226 gene in HEK293 cells was detected by RT-PCR, Western blot and indirect immunofluorescence assay .The purified recombinant plasmid was used to prepare the Ag 85A-CD226 DNA vaccine by liposomal encapsula-tion.The vaccine was administered intragastrically to mice .The activities of NK cells , the cytokine levels in the supernatants of spleen cell cultures and the mRNA level of cytokines in the intestines were evaluated to analyze the immunogenicity of Ag85A-CD226 DNA vaccine.Results The Ag85A-CD226 DNA vaccine was prepared successfully .The expression of Ag85A-CD226 fusion protein was detected in HEK293 cells.The activities of NK cells from mice vaccinated with Ag 85A-CD226 DNA vaccine were higher than those from other control groups (P0.05).Conclusion The Ag85A-CD226 DNA vaccine could significantly enhance Th1 type immune responses systemically and in the intestine as in comparison with those vaccinated with single dose of Ag 85A DNA vaccine or CD226 DNA vaccine.
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The aim of this study is to investigate the immune effects of BCG primary immunization and IL-12 combined with Mycobacterium tuberculosis Ag85A DNA vaccine booster immunization on mice .We randomly divided the mice into 7 groups ,namely PBS negative controls ,BCG controls ,pcAg85A controls ,BCG primary immunization combined with Ag85A booster immunization controls ,BCG primary immunization combined with Ag85A and IL-12 booster immunization controls , BCG primary immunization combined with IL-12 booster immunization controls ,and BCG primary immunization combined with pcDNA3 .1 booster immunization controls .Implementing the immune in procedure of BCG primary immunization and cytokine IL-12 booster immunization combined with mycobacterium tuberculosis Ag85A DNA ,we observed the immune effect on mice by detecting the mice serum total IgG , specific lymphocyte proliferation and cytokine levels in 4 ,6 ,8 weeks after the last immunization .Comparing the mice immunized in the strategy of BCG primary immunization and cytokine IL-12 combined with Mycobacterium tuberculosis Ag85A DNA vaccine strengthening immunization to the mice in other groups by other immune ways ,we found that ,in BCG/Ag85A+ IL-12 groups ,IgG in-creased significantly (P＜ 0 .05) ,specific lymphocyte prolifera-ted significantly ,and after strengthening immunization IFN-γlevels ,IL-2 levels and IL-4 levels in the three periods were 128 .2 ±20.4,190.2±16.51,244.2±39.14 ;146.2±17.29,271.6±16.36and16.36±28.12 ;68.6±6.62,96.6±5.5and5.5± 10 .71 ,respectively ,which were higher than those in other groups (P＜0 .05) .It’s suggested that the immunization way of BCG primary immunization and cytokine IL-12 combined with Mycobacterium tuberculosis Ag85A DNA vaccine booster immu-nization could significantly enhance the humoral and cellular immunity of the bodies ,and provide the basis for further study on protective effect test in animals .
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The goal of this study was to demonstrate the usefulness of an enzyme-linked immunosorbent assay (ELISA) for the serodiagnosis of pulmonary tuberculosis (PTB) and extrapulmonary TB (EPTB). This assay used 20 amino acid-long, non-overlapped synthetic peptides that spanned the complete Mycobacterium tuberculosis ESAT-6 and Ag85A sequences. The validation cohort consisted of 1,102 individuals who were grouped into the following five diagnostic groups: 455 patients with PTB, 60 patients with EPTB, 40 individuals with non-EPTB, 33 individuals with leprosy and 514 healthy controls. For the PTB group, two ESAT-6 peptides (12033 and 12034) had the highest sensitivity levels of 96.9% and 96.2%, respectively, and an Ag85A-peptide (29878) was the most specific (97.4%) in the PTB groups. For the EPTB group, two Ag85A peptides (11005 and 11006) were observed to have a sensitivity of 98.3% and an Ag85A-peptide (29878) was also the most specific (96.4%). When combinations of peptides were used, such as 12033 and 12034 or 11005 and 11006, 99.5% and 100% sensitivities in the PTB and EPTB groups were observed, respectively. In conclusion, for a cohort that consists entirely of individuals from Venezuela, a multi-antigen immunoassay using highly sensitive ESAT-6 and Ag85A peptides alone and in combination could be used to more rapidly diagnose PTB and EPTB infection.
Subject(s)
Adult , Female , Humans , Male , Middle Aged , Antigens, Bacterial , Mycobacterium tuberculosis/immunology , Peptides , Tuberculosis/diagnosis , Antigens, Bacterial/immunology , Case-Control Studies , Enzyme-Linked Immunosorbent Assay , Peptides/immunology , Sensitivity and Specificity , Tuberculosis, Pulmonary/diagnosis , Tuberculosis, Pulmonary/immunology , Tuberculosis/immunologyABSTRACT
Objective To obtain M. Tuberculosis Ag85A protein by prokaryotic expression. Methods The fbpA gene encoding M. Tuberculosis Ag85A protein was amplified by polymerase chain reaction ( PCR) from M. Tuberculosis H37R_V strain. The PCR product was cloned into prokaryotic expression vector pProEXHTb to generate the recombi-nant plasmid pProfbpA, which was then transformed into the competence Escherichia coli BL21 cells. The recombi-nant Ag85A protein was successfully expressed by isopropyl thio-β-D-galactoside(IPTG) induction and purified by the Ni-purification system. The distribution of fbpA gene in different nonpathogenic mycobacterial strains was screened by PCR and ELISA was performed to determine the immunoreactivity of the recombinant Ag85A protein with serum from mice with mycobacterial infections. Results 32 ku Ag85A protein was successfully expressed and purified. It was confirmed by PCR and ELISA that fbpA gene presented in the genomes of M. Tuberculosis H37Rv, H37Ra, BCG, M. Smegmatis, M. Terra, M. Trivial and M. Phlei, but being absent in the genomes of M. Vaccae. The highest Ag85 A antibody titer was found in serum of TB patients and mice infected by M . Tuberculosis H37Rv .Conclusion The recombinant Ag85A protein was successfully expressed and purified.
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Objective: To clone the Ag85 A antigen gene of Mycobacterium tuberculosis and express it in E. coli k802. Methods: The Ag85 A gene was amplified from the genome of Mycobacterium tuberculosis by PCR and was inserted into prokaryotic expressing vector pGEX5T to construct pGEX5T-Ag85A recombinant plasmid. The expression of Ag85A protein in E. coli k802 was induced by IPTG. The expressed protein was purified by affinity chromatography and the antigenicity of the expressed protein was confirmed by Western blotting assay. Results: A band about 0.9 kb in length was obtained by PCR and the recombinant plasmid pGEX5T-Ag85A was successfully constructed. A new band about 58 000 in length was observed after IPTG induction in E. coli. The relative molecular weight of the expressed protein was consistent with that expected. A single protein band of 58 000 in length was obtained after purification. The expressed protein could be specifically recognized by the sera of patients with tuberculosis patients. Conclusion: The Ag85A gene of Mycobacterium tuberculosis has been successfully cloned and expressed in E. coli k802, which paves a way for further studies on diagnosis and therapy of tuberculosis.
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Objective: To use in vivo fluorescence image analysis system for evaluating the efficacies of pVAX1-Ag85A and pVAX1-Ag85B DNA vaccines in treatment of bladder cancer cell-implanted tumors in mice. Methods: Discosomasp red fluorescent protein (DsRed) stably transfected bladder cancer BTT cell line (BTT-DsRed) was established and BTT-DsRed cell-implanted mouse model was constructed. Six days later, 24 BTT-DsRed-bearing mice were randomly divided into pVAX1-Ag85A DNA vaccine group, pVAX1-Ag85B DNA vaccine group, and saline group through injecting the pVAX1-Ag85A, pVAX1-Ag85B, and saline into the right hind limbs of mice, respectively. The growth and metastasis of implanted BTT-DsRed tumors were examined by in vivo fluorescence image analysis system. Results: BTT cell line stably transfected with DsRed (BTT-DsRed) was successfully established. Fluorescence visible mouse model was successfully es-tablished by inoculating BTT-DsRed cells into hind limbs of mice. After treatment with pVAX1-Ag85A or pVAX1-Ag85B for 2 weeks, the in vivo tumor fluorescence intensity in pVAX1-Ag85B group was significantly lower than that in the saline group (P <0.05). After 3 weeks, tumor fluorescence intensities in both pVAX1-Ag85A and pVAX1-Ag85B groups were significantly lower than that in the saline group (P < 0.01). But the efficacies of pVAX1-Ag85A and pVAX1-Ag85B groups were similar (P > 0.05). The distant lymphatic metastasis rate in pVAX1-Ag85B group was significantly lower than those in the saline (25.0% vs 87.5%) and pVAX1-Ag85A groups (25.0% vs 62.5%) (P <0.05). Conclusion: In vivo fluorescence image analysis system can dynamically, sensitively and visually evaluate the anti-tumor effects of DNA vaccines against bladder cancer cell-implanted tumors. Both pVAX1-Ag85A and pVAX1-Ag85B DNA vaccines have anti-tumor effects for bladder cancers.
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Eighty-five complex (85A, 85B and 85C), 35-kDa and superoxide dismutase (SOD) were cloned, expressed and purified as antigens in an enzyme-linked immunosorbent assay (ELISA) to compare the serological reactivity of cows with different shedding levels of Mycobacterium avium subsp. paratuberculosis (MPT). Antibody responses to all recombinant antigens positively increased depending on shedding levels. In particular, antibody responses to the 35 kDa were higher than those to the others in all shedder groups. Also, the mean of O. D. values among Ag 85 complex, 85B showed slightly higher response than others with high sensitivity and specificity in all shedder groups. In receiver operating characteristic (ROC) curve analysis, the result of 35 kDa ELISA yielded an area under the curve value of 0.945 (95% confidence interval = 0.895 . 0.996), which indicated that this 35 kDa is more accurate indicator of MPT infection than other antigens. At the cut-off point recommended by the ROC curve analysis, the sensitivity and specificity of 35 kDa ELISA were higher than those of other antigens with 93.3% and 86.4%, respectively. Finally, a commercially available ELISA kit was used to clarify 200 positive and 200 negative sera. We then re-tested these serum samples with our ELISA test using the 35-kDa antigens. 35 kDa ELISA and commercial kit showed almost similar results in ROC curve analysis even though two of positive sera in commercial kit were negative in 35 kDa ELISA. The sera, which showed difference in the comparison with commercial ELISA kit, they also did not react with 35 kDa in Western blot. These results suggest that a 35-kDa based ELISA can be useful for detecting MPT infection.