Development and verification of a reversed phase high-performance liquid chromatography method for purity determination of recombinant Mycobacterium tuberculosis Ag85b protein stock solution / 中国生物制品学杂志

@#Objective To develop and verify a reversed phase high-performance liquid chromatography method for the determination of the purity of recombinant Mycobacterium tuberculosis(Mtb)Ag85b protein stock solution.Methods Fourfactor,three-level orthogonal test was designed,with the area,trailing factor,peak area and peak area RSD as the evaluation indexes to explore the optimal detection conditions. The methodology verification of specificity,linear range,precision and durability was conducted in accordance with the general principles of Chinese Pharmacopoeia(Volume Ⅳ,2020 edition)9101.Results The results of all the evaluation indexes were good when the elution ratio of organic phase was30% ～ 95%,the detection temperature was 35 ℃,the sample volume was 3 μg,and the elution time of 95% organic phase was 15 min. The method had the linear correlation coefficient(R2)of 0. 998 5,the linear range of 1. 8 ～ 4. 2 μg,the reproducibility RSD of 0. 01%,and the intermediate precision RSD of 0. 16%,with good durability under slight changes of column temperature and flow rate.Conclusion The reversed phase high-performance liquid chromatography method for the purity determination of recombinant Mtb Ag85b protein stock solution was developed,which has good specificity,precision and durability,and can be used for the quality control of recombinant Mtb Ag85b protein stock solution.

Effects of macrophages under the influence of tuberculosis antigen Ag85 on the proliferation and apoptosis of Hodgkin lymphoma KM-H2 cells / 白血病·淋巴瘤

Objective:To explore the effects of macrophages after influenced by tuberculosis antigen Ag85 on the proliferation and apoptosis of Hodgkin lymphoma cells, and to discuss the possible role of tuberculosis infection in the progression of Hodgkin lymphoma.Methods:The indirect co-culture system between Hodgkin lymphoma cell line KM-H2 and human monocytic leukemia cell line THP-1 (simulated macrophage) was established by using Transwell nesting. KM-H2 cells were cultured as KM-H2 group alone, KM-H2 cells interfered with Ag85 were taken as KM-H2+Ag85 group, and KM-H2 cells co-cultured with THP-1 cells were taken as KM-H2+THP-1 group. The co-culture system of KM-H2 cells and THP-1 cells interfered by Ag85 was taken as KM-H2+THP-1+Ag85 group. The proliferation of KM-H2 cells in each group was detected by using CCK-8 assay, and the growth curve was drawn. The apoptosis of cells in each group was detected by using flow cytometry. The mRNA expression levels of p53, c-myc, bcl-2 and vascular endothelial growth factor receptor 3 (VEGFR3) in each group were detected by using quantitative real-time fluorescence polymerase chain reaction (qRT-PCR). The expressions of bax and bcl-2 proteins were detected by using Western blotting.Results:The cell proliferation ability of KM-H2+Ag85 group was higher than that of KM-H2 group (all P = 0.001) after 24 and 48 h culture, but the cell proliferation ability of KM-H2+THP-1 group was lower than that of KM-H2 group after 24 h, 48 h and 72 h culture (all P < 0.05). The cell proliferation ability of KM-H2+THP-1+Ag85 group was lower than that of KM-H2 group after 48 h and 72 h culture (all P < 0.05), but the cell proliferation ability of KM-H2+THP-1+Ag85 group was enhanced after 24 h and 48 h culture compared with KM-H2+THP-1 group, and there was no statistically significant difference between the two groups after 72 h culture ( P > 0.05). The apoptosis rate of KM-H2+Ag85 group was lower than that of KM-H2 group [(0.92±0.80)% vs. (6.02±1.63)%, P < 0.001], and the apoptosis rate of KM-H2+THP-1 group [(8.57±0.57)%] was higher than that of KM-H2 group ( P < 0.05). The apoptosis rate [(0.60±0.13)%] in KM-H2+THP-1+Ag85 group was lower than that in KM-H2+THP-1 group ( P < 0.001). The relative expression of bcl-2 and VEGFR3 mRNA in KM-H2+Ag85 group was higher than that in KM-H2 group ( P = 0.018, P = 0.017), while the relative expression of c-myc mRNA in KM-H2+Ag85 group was lower than that in KM-H2 group ( P = 0.016), and there was no statistically significant difference of p53 mRNA relative expression level between the both groups ( P > 0.05).The relative expression of p53 mRNA in KM-H2+THP-1+Ag85 group was lower than that in KM-H2+THP-1 group ( P = 0.048), while the relative expressions of bcl-2 and VEGFR3 mRNA in KM-H2+THP-1+Ag85 group were higher than those in KM-H2+ THP-1 group ( P = 0.016; P = 0.021). The expression of bax protein in KM-H2+Ag85 group was lower than that in KM-H2 group ( P = 0.019), and bcl-2 protein was more than that in KM-H2 group ( P = 0.001). The expression of bax protein in KM-H2+THP-1+Ag85 group was lower than that in KM-H2+THP-1 group ( P = 0.011), but there was no statistically significant difference in the expression of bcl-2 protein between the two groups ( P > 0.05). Conclusions:Tuberculosis antigen Ag85 may inhibit the apoptosis of Hodgkin lymphoma KM-H2 cells and enhance the proliferative activity by affecting the function of macrophages.

Assessment of immunological markers and booster effects of Ag85B peptides, Ag85B, and BCG in blood of BCG vaccinated children: a preliminary report

PURPOSE: In the present study, the protective immunological markers in serum and peripheral blood mononuclear cells (PBMCs) of bacillus Calmette-Guerin (BCG) vaccinated and unvaccinated children were evaluated after vaccination. Further, PBMCs of children with low protective levels were boosted with BCG, Ag85B, and Ag85B peptides to study their booster effects to increase waning BCG induced immunity. MATERIALS AND METHODS: Fifty children from 1 month to 18 years of age were randomized for the study. Blood samples were collected from 27 participants with/without BCG vaccination. Immunological markers (anti-BCG, interferon gamma [IFN-gamma], and adenosine deaminase activity) were assessed in both serum and PBMCs of children. Children with low levels of protective immunological markers were further recruited and their PBMCs were boosted with BCG, Ag85B, and Ag85B peptides. RESULTS: Children in age group of 4-6 years were associated with significantly (p<0.05) higher BCG-specific IgG and IFN-gamma levels compared to those in age group greater than 10 years. Vaccinated children had greater repertoire of immunological memory which on in vitro stimulation with BCG showed increase in BCG-specific response compared to unvaccinated controls. Assessment of booster effects of BCG, Ag85B, and Ag85B peptides in PBMCs of children revealed greater potential of peptides to boost BCG induced immunity compared to BCG and Ag85B. CONCLUSION: To conclude, children within age 4-6 years are associated with high immunological markers which eventually diminish with age thereby suggesting need for booster dose in later years. Mycobacterium tuberculosis peptides along with BCG may be used as attractive candidates to boost such waning BCG induced immunity in children.

Preparation of an Ag85A-CD226 DNA vaccine and evaluation of its immunogenicity in a mouse mod-el / 中华微生物学和免疫学杂志

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.

Immunologic evaluation and validation of methods using synthetic peptides derived from Mycobacterium tuberculosis for the diagnosis of tuberculosis infection

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.

Therapeutic Effects of Mycobacterial Secretory Proteins Against Established Asthma in BALB/c Mice

PURPOSE: Live/killed mycobacteria and culture supernatants can suppress asthmatic reactions. This study investigated whether mycobacterial secretory proteins have therapeutic effects on asthma. METHODS: Mycobacterium bovis bacille Calmette-Guerin (BCG; 2x105 CFUs) and mycobacterial secretory proteins (Ag85 complex, 38-kDa protein or MPB70; 4 or 20 microg) were administered intraperitoneally to female BALB/c mice with established airway hyperresponsiveness. One week after treatment, the mice underwent a methacholine challenge test, and then inflammatory cell numbers in bronchoalveolar lavage fluid (BAL) and around bronchi (<500 microm), and cytokine levels in splenocyte supernatants, were assessed. RESULTS: BCG and all of the tested secretory proteins significantly improved airway sensitivity compared to baseline values (P<0.05). The secretory protein Ag85 complex significantly suppressed airway reactivity also (P<0.05), while 38-kDa protein significantly suppressed reactivity and maximal narrowing (P<0.05). The number of eosinophils in BAL and around bronchi, and the goblet cell proportion, were also significantly reduced in mice in both the BCG and secretory protein groups compared to the asthma control group. IFN-gamma/IL-5 ratios were significantly higher in mice treated with BCG, 4 microg MPB70 or 4 microg 38-kDa protein than in asthma control mice (P<0.05), and were negatively associated with airway hyperresponsiveness, peribronchial eosinophil numbers and goblet cell proportion (all P<0.05). IL-17A was positively correlated with IL-5 (r=0.379, P<0.001), maximal airway narrowing, peribronchial eosinophil numbers and goblet cell proportion (all P<0.05). CONCLUSIONS: Secretory proteins from BCG and M. tuberculosis and live BCG were effective against established asthma, their effects being accompanied by increased IFN-gamma/IL-5 ratios. Thus, allergic asthma could be effectively treated with mycobacterial secretory proteins.

Clone of Mycobacterium tuberculosis Ag85A gene and its prokaryotic expression / 第二军医大学学报

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.

Prokaryotic expression, purification and immunoreactivity of Mycobacterium tuberculosis Ag85A protein / 基础医学与临床

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.

Analysis of immunogenicity of tuberculosis fusion protein consisting of Ag85B, Mpt64 and HspX antigens expressed in replication and dormancy bacilli / 中华微生物学和免疫学杂志

Objective To construct protective immunity to Mycobncterium tuberculosis latent infection, a novel fusion protein consisting of HspX, the 190 to 198 peptide of Mpt64 and Ag85B, which were confirmed to be the effective protective antigens mainly expressed in the dormancy and exponential phase of growth, was constructed and its immunogenicity was investigated. Methods Ag85B and Mpt64190-198-HspX sequences were amplified by PCR and cloned into plasmids pET-28a. The fusion protein, Ag85BMpt64190-198-HspX (AMH) was expressed in E. coli BL21 and purified with Ni-NTA resins. C57BL/6 mice were immunized three times at 2-week intervals subcutaneously with AMH formulated with the adjuvant composed of dimethyl-dioctyldecyl ammonium bromide (DDA) and BCG polysaccharide nucleic acid (BCGPSN). Humoral and cell-mediated immunity responses were analyzed at five weeks after the last injection. Results AMH was expressed stably in E. coli and could be purified well by Ni-NTA affinity chromatography. C57BL/6 mice immunized with AMH subunit vaccine generated specific cellular and humoral immunologic response to the stimulation of Ag85B, Mpt64190-198 and HspX. Conclusion It suggested that AMH was a promising candidate antigen of tuberculosis subunit vaccine.

In vivo fluorescence image analysis system in assessing efficacies of pVAX1-Ag85A and pVAX1-Ag85B DNA vaccines in treatment of bladder cancer cell-implanted tumors in mice / 中国肿瘤生物治疗杂志

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.

Purification of Native Ag85 Complex, 38-kDa and MTB12 Protein Antigens from the Culture Filtrate of Mycobacterium tuberculosis

The purification of immunodominant native protein antigens from the culture filtrates of Mycobacterium tuberculosis is needed for the development of new vaccines and immunodiagnostic reagents against tuberculosis. In the present study, we conducted large scale purification of well-known secreted antigens, Ag85 complex, 38-kDa, and MTB12, from the culture filtrate proteins (CFPs) prepared from M. tuberculosis H37Rv grown as a surface pellicle on synthetic Sauton medium. The protein and antigen concentrations of culture filtrates were sufficiently increased after 6 week of culture. The MTB12 antigen was detected as early as 1 week of culture, and Ag85 complex and 38-kDa antigen were detected after 2 and 3 week of culture, respectively, by immunodiffusion with specific antiserum against 100-fold concentrated culture filtrates. For large-scale purification, the six-week-culture filtrates of M. tuberculosis H37Rv diluted 2.5-fold with 20 mM Tris-HCl, (P)H 8.3 were subjected to anion-exchange chromatography. The CFPs were eluted with 100 mM NaCl-20 mM Tris-HCl, pH 8.3 and concentrated by ultrafiltration. The concentrated CFPs were fractionated with ammonium sulfate, and followed by hydrophobic interaction chromatography and anion-exchange chromatography (FPLC). Eventually, 10 mg of Ag85 complex, 0.56 mg of 38-kDa, and 1.81 mg of MTB12 antigens were purified from 1 liter of the six-week-culture filtrates of M. tuberculosis H37Rv which contained 307.81 mg of protein of culture filtrate.

IFN-gammamRNA Expression in Tuberculous Pleural Lymphocytes After in vitro Stimulation with M. tuberculosis Antigens / 결핵및호흡기질환

BACKGROUND: IFN-gamma is the main effector mediator of the host immune response against Mycobacterium tuberculosis. Evaluating the IFN-gamma gene expression in response to M. tuberculosis antigens may help in elucidating the host defense mechanism against M. tuberculosis and in the development of a vaccine. METHODS: The IFN-gamma mRNA expression in the lymphocytes obtained from pleural effusions from tuberculous pleurisy patients (TB-PLC) after in vitro stimulation with whole cell M. tuberculosis(H37Rv), purified protein derivatives(PPD), man-lipoarabinamman (man-LAM), ara-LAM and Antigen 85B(Ag85B) were evaluated. The degree of IFN-gamma mRNA expression was determined by a semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) method. RESULTS: M. tuberculosis induced the expression of IFN-gamma mRNA in the TB-PLC in time and dose dependent manners. The PPD and Ag85B induced high levels of IFN-gamma mRNA expression in the TB-PLC. However, man-LAM inhibited IFN-gamma mRNA expression in the TB-PLC, while ara-LAM did not. CONCLUSION: IFN-gamma mRNA expression in TB-PLC is stimulated by PPD and Ag85B, but inhibited by man-LAM.

Anti-tumor effect of mycobacterium Ag85B/IL-2 fusion protein on syngeneic mice bearing bladder cancer / 第三军医大学学报

Objective To study the anti-tumor effect of mycobacterium Ag85B/IL-2 fusion protein on syngenic mice bearing bladder cancer. Methods After being implanted BTT739 bladder transitional carcinoma cells from tumor bearing mice, 80 T739 mice were divided into Ag85B protein, BCG, IL-2 and normal saline groups (n=20). Mycobacterium Ag85B/IL-2 protein was locally injected to the mice at the site of implanting tumor in the trial group, and Ag85B protein, BCG, IL-2 and normal saline to the control group mice. The weight and volume of tumor and the survival period were recorded after treatment. Results The average weight of Ag85B/IL-2 fusion protein treatment group was significantly lower than those of Ag85B, BCG,IL-2 and normal saline group (P

Construction and expression of the eukaryotic coexpression plasmid of Mycobacterium tuberculosis Ag85B and MPT64 gene / 重庆医科大学学报

Objective:To construct an eukaryotic coexpression plasmid containing Mycobacterium tuberculosis Ag85B and MPT64 gene.Methods:Mycobacterium tuberculosis Ag85B and MPT64 gene were cloned into pBudCE4.1 to construct recombinant plasmid pBud85B-MPT.The recombinant plasmid was transfected into COS-7 cells,and its expression of Ag85B and MPT64 was assesed by RT-PCR.Results:Mycobacterium tuberculosis Ag85B and MPT64 were detected in transfected COS-7 cells.Conclusion:The recombinant plasmid pBud85B-MPT can express Ag85B and MPT simultaneously in COS-7 cells which provides the basis for further investigation of DNA vaccine against tuberculosis.