Construction of NKG2D CAR-NK92 cells and its killing effect on multiple myeloma cells / 细胞与分子免疫学杂志

Objective This study aims to construct and identify the chimeric antigen receptor NK92 (CAR-NK92) cells targeting NKG2D ligand (NKG2DL) (secreting IL-15Ra-IL-15) and verify the killing activity of NKG2D CAR-NK92 cells against multiple myeloma cells. Methods The extracellular segment of NKG2D was employed to connect 4-1BB and CD3Z, as well as IL-15Ra-IL-15 sequence to obtain a CAR expression framework. The lentivirus was packaged and transduced into NK92 cells to obtain NKG2D CAR-NK92 cells. The proliferation of NKG2D CAR-NK92 cells was detected by CCK-8 assay, IL-15Ra secretion was detected by ELISA and killing efficiency was detected by lactate dehydrogenase (LDH) assay. The molecular markers of NKp30, NKp44, NKp46, the ratio of apoptotic cell population, CD107a, and the secretion level of granzyme B and perforin were detected using flow cytometry. In addition, the cytotoxic mechanism of NKG2D CAR-NK92 cells on the tumor was verified by measuring the degranulation ability. Moreover, after NKG2D antibody inhibited effector cells and histamine inhibited tumor cells, LDH assay was utilized to detect the effect on cell-killing efficiency. Finally, the multiple myeloma tumor xenograft model was constructed to verify its anti-tumor activity in vivo. Results Lentiviral transduction significantly increased NKG2D expression in NK92 cells. Compared with NK92 cells, the proliferation ability of NKG2D CAR-NK92 cells was weaker. The early apoptotic cell population of NKG2D CAR-NK92 cells was less, and NKG2D CAR-NK92 cells had stronger cytotoxicity to multiple myeloma cells. Additionally, IL-15Ra secretion could be detected in its culture supernatant. NKp44 protein expression in NKG2D CAR-NK92 cells was clearly increased, demonstrating an enhanced activation level. Inhibition test revealed that the cytotoxicity of CAR-NK92 cells to MHC-I chain-related protein A (MICA) and MICB-positive tumor cells was more dependent on the interaction between NKG2D CAR and NKG2DL. After stimulating NKG2D CAR-NK92 cells with tumor cells, granzyme B and perforin expression increased, and NK cells obviously upregulated CD107α. Furthermore, multiple myeloma tumor xenograft model revealed that the tumors of mice treated with NKG2D CAR-NK92 cells were significantly reduced, and the cell therapy did not sensibly affect the weight of the mice. Conclusion A type of CAR-NK92 cell targeting NKG2DL (secreting IL-15Ra-IL-15) is successfully constructed, indicating the effective killing of multiple myeloid cells.

Construction of CAR-T cells targeting CS1 and analysis of their antitumor activity in vitro / 生物工程学报

We constructed the CS1-targeted second- and third-generation CAR-T cells with genetic engineered 4-1BB or/and ICOS as a costimulatory signaling molecule by use of lentiviral platform. The CS1-targeted second-generation CAR-T cells with ICOS or 4-1BB had similar anti-neoplastic activity. When effector/target ratio was 1:1, the CAR-T cells with ICOS showed better killing effect on IM9-lucgfp cells than those with 4-1BB. However, The CS1-targeted third-generation CAR-T cells exihibited lower cytolytic capacity against IM9-lucgfp cells than the CS1-targeted second-generation CAR-T cells when the ratio of effector/target was 1:1, 2:1 or 5:1. When the ratio of effector/target was 10:1, the killing efficacy of both the second- and third-generation CAR-T cells against IM9-lucgfp cells was more than 85%, significantly higher than that of the control T cells. Taken together, both the CS1-targeted second- and third-generation CAR-T cells with ICOS or/and 4-1BB could efficiently kill CS1-positive multiple myeloma cells, but the CS1-targeted second-generation CAR-T cells had more potent killing effect on CS1-positive multiple myeloma cells than the CS1-targeted third-generation CAR-T cells.

Construction and function of Glypican-3-targeted fourth-generation chimeric antigen receptor T cells (secreting IL-7 and CCL19) / 生物工程学报

Adoptive immunotherapy based on chimeric antigen receptor-modified T cells (CAR-T) is one of the most promising strategies to treat malignant tumors, but its application in solid tumors is still limited. Glypican-3 (GPC3) is a meaningful diagnostic, therapeutic, and prognostic biomarker for hepatocellular carcinoma (HCC). The second/third generation GPC3-targeted CAR-T cells are generated to treat HCC. In order to improve the therapeutic effect, we constructed a fourth-generation lentiviral vector to express GPC3 CAR, human interleukin-7 (IL-7) and CCL19. Then the lentiviral vector and packaging plasmids were co-transfected into HEK293T cells to generate CAR lentiviral particles. Human T lymphocyte cells were transduced with CAR lentiviral to develop the fourth-generation GPC3-targeted CAR-T cells (GPC3-BBZ-7×19). In vitro, we used cell counting, transwell assay, luciferase bioluminescence assay and flow cytometry to compare the proliferation, chemotaxis, cytotoxicity and subtype distribution between GPC3-BBZ-7×19 CAR-T cells and the second generation GPC3-targeted CAR-T cells (GPC3-BBZ). In vivo, we established GPC3-positive HCC xenograft model in immunodeficient mice, then untransduced T cells (non-CAR-T) or GPC3-BBZ-7×19 CAR-T cells were injected. Tumor growth in mice was observed by bioluminescence imaging. Results showed that compared with GPC3-BBZ CAR-T, GPC3-BBZ-7×19 CAR-T cells had stronger proliferation, chemotactic ability, and higher composition of memory stem T cells (Tscm) (P values<0.05). However, there were no significant difference in cytotoxicity and cytokine secretion between them. In addition, GPC3-BBZ-7×19 CAR-T cells could significantly eliminate GPC3-positive HCC xenografts established in immunodeficient mice. Therefore, the fourth-generation GPC3-targeted CAR-T cells (secreting IL-7 and CCL19) are expected to be more durable and effective against HCC and produce tumor-specific memory, to provide a preclinical research basis for future clinical trials.

Construction of a novel lentiviral vector knocking down PD-1 via microRNA and its application in CAR-T cells / 生物工程学报

By inserting microRNAs into the intron of EF1α promoter, we constructed a novel lentiviral vector knocking down PD-1 gene via microRNA and applied it to CAR-T cells. Lentiviral transduction efficiency and PD-1-silencing efficiency were detected by flow cytometry. PD-1 expression was detected by Western blotting. Relative expression of microRNA was measured by Q-PCR. Cytotoxicity of CAR-T cells based on this vector was tested by luciferase bioluminescence and flow cytometry. Compared with lentiviral vector with microRNA transcribed by U6 promotor, the transduction efficiency of lentiviral vector with microRNA which was inserted into the intron of EF1α promoter was more significant, and the knockdown rate of PD-1 was more than 90%, which was validated by flow cytometry and Western blotting. And the relative expression level of microRNA in Jurkat cells transduced with this novel lentiviral vector was shown by Q-PCR. Compared with normal CAR-T cells, CAR-T cells based on this vector showed stronger cytotoxicity against PD-L1 positive Raji cells. We successfully constructed a novel lentiviral vector that knocked down PD-1 via microRNA and verified the superiority of its transduction efficiency and knockdown efficiency of PD-1. CAR-T cells based on this vector can exert a more powerful cytotoxicity, thus providing theoretical support for the subsequent treatment of PD-L1 positive tumors.

Metabolomic analysis of human cerebrospinal fluid in patients with tuberculous meningitis using ultra high performance liquid chromatography tandem mass spectrometry / 中华检验医学杂志

Objective:To study the non-target metabolomics analysis and to analyze the metabolomic changesof cerebrospinal fluid (CSF) in patients with tuberculous meningitis.Methods:Case-control study. From July 2018 to July 2019, 20 cerebrospinal fluid specimens of diagnosed patients with tuberculous meningitis were collectedin the department of neurology from the first medical center of the PLA general hospital and the eighth medical center of the PLA general hospital and 20 CSF without tuberculous meningitis as the control. Among them, there were 12 males and 8 femalesin the tuberculous meningitis group, aged (37.9±16.1) years; there were 13 males and 7 femalesin the control group, aged (34.7±14.8) years. Using ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS) technology with three different mode, namely reverse phase chromatography positive ion mode, reverse phase chromatography negative ion mode and hydrophilic chromatography positive ion mode,to detectthe metabolic fingerprints of patients′CSF and analyzed by SIMCA software for orthogonal partial least squares discriminant analysis (OPLS-DA). The variable importance projection value of OPLS-DA model (threshold value>1) plus the P value of t-test (P<0.05) was applied to find the differential metabolites in the cerebrospinal fluid of the two groups of patients.Results:Ten differential metabolites were found in CSF, including L-isoleucine, L-phenylalanine, L-kynurenine, L-methionine, L-tyrosine acid, dimethylglycine, L-alanine, L-threonine, L-histidine and L-lysine, and all of them were up-regulated in the tuberculous meningitis group.Conclusion:Changesof the amino acid metabolism found in the cerebrospinal fluid of tuberculous meningitis patients can provide basis for differential diagnosis and basic molecular research of tuberculous meningitis.

Construction and characterization of the fourth-generation CAR-T cells targeting fibroblast activation protein (FAP) / 中华微生物学和免疫学杂志

Objective:To construct the second and fourth generations of CAR-T cells targeting fibroblast activation protein (FAP) on the surface of stromal carcinoma-associated fibroblasts and compare their characteristics in vitro and in vivo. Methods:ELISA was used to detect the cytokines secreted by CAR-T cells. Cell proliferation and viability were analyzed by counting. Chemotactic ability was tested by Transwell migration assay. Distribution of T cell subsets was analyzed by flow cytometry. Cytotoxicity was assessed by luciferase bioluminescence. The safety and therapeutic effects were evaluated in a NOG mouse model of metastatic human lung cancer.Results:The expression rates of the second and fourth generations of CAR-T cells (h4BBz CAR-T and h4BBz-7.19 CAR-T) were (74.280±4.384)% and (67.220±4.013)%, respectively. The h4BBz-7.19 CAR-T cells had better in vitro proliferation and chemotactic activity than h4BBz CAR-T cells as they were able to secrete IL-7 and CCL19, while the viability of h4BBz-7.19 CAR-T cells was comparable to that of h4BBz CAR-T cells. There was no significant difference in the expression rate of h4BBz CAR or h4BBz-7.19 CAR between CD4 + T and CD8 + T cells. The proportions of both Naive cells and T memory stem cells (TSCM) in CD4 + and CD8 + T cells were higher in h4BBz-7.19 CAR-T cells than in h4BBz CAR-T cells. Moreover, h4BBz-7.19 CAR-T cells possessed stronger specific cytotoxicity on the target cancer cells than h4BBz CAR-T cells when the ratio of effectors/targets was low ( P1∶1=0.004, P2∶1=0.000 6, P5∶1<0.000 1, P10∶1=0.022, P20∶1=0.116), while the expression of PD-1 on the surface of h4BBz-7.19 CAR-T cells was lower than that on h4BBz CAR-T cells. In the NOG mouse model of metastatic human lung cancer, h4BBz-7.19 CAR-T cells could slow the tumor growth and prolong the survival time of mice without causing weight loss or pathological changes in the organs. Conclusions:The fourth-generation CAR-T cells targeting FAP were shown to have stronger proliferation, better penetration and more potent specific cytotoxicity by secreting IL-7 and CCL19 and could slow the tumor growth and prolong survival by improving tumor immunosuppressive microenvironment. This study provided reference for the clinical application of the fourth generation of CAR-T cells.

Eukaryotic expression, protein purification and biological effects research of human CS1-Fc fusion protein / 生物工程学报

Signaling lymphocyte activation family 7 (SLAMF7/CS1) is a cell surface glycoprotein that is highly expressed in multiple myeloma cells. CS1 is a sensitive and specific biomarker for multiple myeloma. CAR-T cell immunotherapy is a new method for the treatment of multiple myeloma. CS1 CAR-T cell immunotherapy has good effect on relapsed refractory multiple myeloma. To detect the expression efficiency of CS1 CAR on CS1 CAR-T cells and to find an auxiliary means to CAR-T cell immunotherapy, we prepared a CS1-Fc fusion protein. First, the extracellular domain of CS1 was amplified from the existing plasmid by PCR and ligated with human IgG1-Fc fragment by overlap extension PCR. The recombinant fragment was ligated into pMH3 eukaryotic expression vector. After restriction enzyme digestion and DNA sequencing, the pMH3-CS1-Fc-his recombinant plasmid was successfully constructed. The recombinant plasmid was transfected into Chinese hamster ovary cell (CHO-S) by liposome. The expression of the CS1-Fc fusion protein in CHO-S cells was identified by flow cytometry after G418 pressure screening. Next, the CS1-Fc fusion protein was purified by nickel column. Western-blot analysis showed that molecular weight of the fusion protein was about 70 kDa was identified by Western blotting. The CS1-Fc fusion protein couldeffectively detect the expression rate of CS1 CAR and promote the activation, proliferation andcytokines secretion of the CS1 CAR-T cells. The results will lay the experimental foundation for the in vitro detection and potentiation of CAR-T cells in multiple myeloma treated with CS1 CAR-T cell.

Pilot-scale preparation of clinical-grade third generation lentivirus / 生物工程学报

Gene therapy is a rapidly developing field. The most widely used technique for foreign gene transfer is lentiviral-mediated gene therapy. Lentiviral vector has been developed from the first generation to the third generation in terms of safety. The preparation of lentiviruses with high titer remains difficult. In this study, a Fibra-Cel sheet carrier was used as an HEK293T cell carrier matrix, and several sterile cell culture spinners were combined and cultured on a roller bottle machine to scale up the adherent cells. The virus titer was maximized by screening the factors to optimize the lentivirus titer in the third-generation lentivirus packaging process one by one. Fibra-Cel sheet vector was successfully used as the matrix of HEK293T cell adhesion to culture adherent cells at large scale. The optimal conditions for large-scale preparation of the third-generation lentivirus by bottle roller were screened and three batches of lentiviruses were produced on pilot scale. The production time of lentivirus was shortened from 120 hours to 54 hours from plasmid transfection to virus collection; in terms of cost, a rolling bottle machine was used instead of a bioreactor, leading to lower cost and no need for repeated sterilization during the whole process. The safe, effective and low-cost operation of successful production will provide a technical base for the large-scale preparation of lentivirus and thus lay a firm foundation for its clinical application.

Exploration of the serum differential biomarkers for osteoarticular tuberculosis based on matrix-assisted laser desorption/ionization time of flight mass spectrometry / 中华检验医学杂志

Objective Toinvestigatestatistically significant peptide peaks as biomarkersto diagnose osteoarticular tuberculosis, matrix-assisted laser desorption/ ionization time of flight mass spectrometry (MALDI-TOF MS) was applied to identify the characteristic fingerprint among the serum of patients with osteoarticular tuberculosis, rheumatoid arthritis and healthy adults.Methods Clinical Study. Serum samples of untreatedpatients with osteoarticular tuberculosis and rheumatoid arthritis were collected from August 2018 to December 2018, and serum samples of healthy adults from physical examination were collected as control. After analysis with MALDI-TOF MS, the serum peptide fingerprint datawas imported into software, and protein polypeptide peaks with obvious differences were screened to establish diagnostic models.Results Established the diagnostic model of osteoarticular tuberculosis and healthy adults with m/z 2943.9, 5929.6, 7615.4 and 9033.8 as differential protein polypeptides, the diagnostic model of osteoarticular tuberculosis and rheumatoid arthritis with m/z 4195.6, 5847.6, 5929.6 and 7748.6 as differential protein polypeptides. To these two models, the sensitivity were 95.00％ and 97.50％, respectively. The specificity were 85.71％ and 88.46％, respectively. The accuracy rates were 89.58％ and 92.39％, respectively. The AUC value of ROC curves were 0.8859 and 0.8709, respectively. Conclusions By mass spectrometry and software analysis, the serum protein polypeptides with statistical difference were found successfully. The related diagnostic modelsarealso established, which has certain reference value for auxiliary diagnosis of osteoarticular tuberculosis.

Function of four pairs of genes in toxin-antitoxin system of Mycobacterium tuberculosis / 中国人兽共患病学报

We discussed the function of four pairs of genes in the toxin-antitoxin system of Mycobacterium tuberculosis,providing theoretical foundation and scientific basis for studying the transmission mechanism of Mycobacterium tuberculosis.Four pairs of genes which belong to VapBC family,including four VapC genes (Rv1720c,Rv2103c,Rv2494,Rv3408) and four VapB genes (Rv1721c,Rv2104c,Rv2493,Rv3407) were chosen.We constructed a serial of arabinose-induced hybrid plasmid system in Escherichia coli and a serial of acetamide-induced hybrid plasmid system in Mycobacterium smegmatis respectively,in order to observe the potential inhibition effect of VapC and the release inhibition of homologous VapB.Results showed that only one toxin gene(Rv2103c) showed the function of bacteriostasis in both E.coli and M.smegmatis and the homologous antitoxin gene(Rv2104c) could release the inhibition of growth.We built the inducible systems of VapBC family in both E.coli and M.smegmatis respectively and found only a pair of toxin and antitoxin genes(Rv2103c,Rv2104c) had the function of inhibition and release for the growth of bacteria.And two pairs of toxin genes(Rv1720c,Rv2494) did not have the function of inhibition for the growth of both E.coli and M.smegmatis.Whereas,another toxin gene VapC47(Rv3408) also did not have the bacteriostastic activity,only this result was not consistent with the existing literature.We speculated that the reason for this kind of difference may be the different inducible systems we used.Cause the other three results were consistent with all existing literature and the doubtful result also appeared in other reports,so our protocol could be confirmed as reliable,and we would use it to build inducible systems and make further functional identification of certain toxin and antitoxin genes that we are interested in.

Role of ICOS on in-vitro cultured human PBMC Treg / 中国免疫学杂志

Objective:To investigate the role of mTOR in regulation of ICOS expression in human blood regulatory T cells. Methods:Isolation of Treg cells from human PBMC using MACS beads. We detected the ICOS expression on purified Treg cells and Treg cells viability using flow cytometry in anti-CD3 plus anti-CD28 ( antibody or beads) or anti-CD3 plus ICOSL-Fc for 3 days and 7 days. CFSE labeling human PBMC cells and in vitro cultured Treg mixed, Treg contact inhibition activity was detected by flow analysis. Results:After in vitro stimulation of Treg cells in the presence of anti-CD3+anti-CD28 for 3 days, there was no significant statistic difference in viability between ICOS+(92. 00±2. 69)% and ICOS-(90. 30±3. 53)% Treg-cells. After cultured for 7 days,the decreased ICOS+ Treg cells percentage within total Treg cells from ( 40. 20 ± 1. 83 )% to ( 11. 60 ± 1. 10 )% compared with that of 3 days. Further more,the ICOS expression level between stimulated with anti-CD28 or ICOSL-Fc condition group,compared with the ICOS MFI in the condition of anti-CD3 plus anti-CD28 treatment for 3 days was (2410. 0±746. 4) obviously higher than (403. 30±74. 42), that of the group treated with anti-CD3 plus ICOSL-FC. Rapamycin could partially suppress Treg cells ICOS expression,but unaffected the Treg suppression ability. Conclusion:ICOS expression level may not important for in vitro cultured human PBMC Treg cells survival although mTOR signling is important for regulation ICOS expression on in-vitro cultured Treg cells,but the ICOS expression on Treg regulated by multiply signaling pathways. CD28 signaling is the key stimulation factor for ICOS upregulation on in-vitro cultured Treg cells compared to ICOSL signaling.

Influence of EGFR in B[a]P-induced SIRT1 activation in human bronchial epithelial cells / 吉林大学学报(医学版)

Objective:To investigate the role of epidermal growth factor receptor (EGFR)in the regulation of B[a]P-induced silent information regulator 1 (SIRT1 ) activation in the human bronchial epithelial cells (BEAS-2B),and to clarify the relationship between EGFR/SIRT1 signal transduction pathway and the occurrence and development lung cancer.Methods:The prediction analysis of transcriptional factor binding sites of SIRT1 was performed by MOTIF SearchTM software.The primary cultivated BEAS-2B cells were divided into control group (without B[a]P exposure)and B[a]P groups (the cells were exposed to B[a]P for 6,12,24,48 h).RT-PCR and Western blotting method were carried out to detect the EGFR mRNA and protein expression levels.The BEAS-2B cells transfected with SIRT1 promotor luciferase reporter gene plasmid were treated with human epidermal growth factor (hEGF)and Genistein (tyrosine protein kinase inhibitor)for 24 h,the morphology of BEAS-2B cells was observed by inverted microscope, and luciferase reporter assay was used to test the SIRT1 transcriptional activity.The human lung tissue biopsies were acquired and the immunohistochemical analysis was used to determine the EGFR protein expression level.Results:The transcriptional factor binding sites of SIRT1 contained EGF, 2Fe-2S and vWF.Compared with control group,the expression levels of EGFR mRNA in B [a]P groups were increased in a time-dependent manner,and reached the peak at 12 h (P < 0.05);the EGFR protein expression levels were also increased (P <0.05).The SIRT1 luciferase activity in hEGF group was increased compared with control group (P <0.05);when hEGF and B[a]P worked together,the SIRT1 luciferase activity was increased even further (P <0.001). The cells showed arrangement and morphologic changes gradually when the B[a]P concentration was above 30 μmol · L-1. Genistein (30 μmol · L-1 )inhibited the increase of SIRT1 luciferase activity induced by B [a]P ,and there was significant difference compared with control group (P <0.05).The immunohistochemistry results showed that EGFR expression level in lung cancer tissue was higher than that in normal lung tissue (P < 0.001).Conclusion:EGFR can regulate the B [a]P-induced SIRT1 expression in BEAS-2B cells,and to cause lung chronic inflammation;EGFR/SIRT1 signal transduction pathway may play a role in the occurrence and development of lung cancer.

Integrating immunomagnetic bead enrichment with immunochromatography for the detection of in-fluenza A virus / 中华微生物学和免疫学杂志

Objective To establish a novel method by integrating immunomagnetic bead enrich-ment with immunochromatography for the detection of influenza A virus. Methods The immunomagnetic beads were prepared by using EDC/NHS method and then coupled with monoclonal antibodies against influ-enza A virus. A direct immunomagnetic beads-based immunochromatography for the detection of influenza A virus was developed by using double-antibody sandwich method and immunochromatography, which was fur-ther combined with immunomagnetic separation to establish the novel integrated method of immunomagnectic bead enrichment and immunochromatography. Clinical throat swab samples collected from patients with influ-enza A virus infection and healthy subjects were analyzed by the novel method and the results were compared with those by using the conventional colloidal gold immunochromatography to evaluate the specificity, sensi-tivity and positive coincidence rate of this established method. Results The direct immunomagnetic beads-based immunochromatography and the colloidal gold immunochromatography showed no significant differences in specificity and sensitivity and could be used to identify influenza A virus-positive samples with cycle threshold ( Ct) values less than or equal to 22 obtained by real-time PCR assay. The integrated method could identify positive samples with Ct values less than or equal to 28, indicating that the novel method was more sensitive. Conclusion The novel method by integrating immunomagnetic bead enrichment with immunochroma-tography was successfully established and suitable for the rapid and on-site detection of influenza A virus.

Study on the population-genetics of Mycobacterium tuberculosis from Sichuan Basin in China / 中华流行病学杂志

Objective To explore the population-genetics characteristics of Mycobacterium tuberculosis (MTB) prevailing at the Sichuan basin of China.Methods A total of 413 MTB strains collected from Sichuan basin were genotyped by large sequence polymorphism (LSP) and 15 loci variable number tandem repeat (VNTR).Difference between the distribution of lineage population was analyzed by x 2-test and the discriminatory ability of each VNTR locus was evaluated under the Hunter-Gaston Discriminatory Index (HGI).Both phylogeny on population level and genetic structure were demonstrated through N-J tree and the Minimal Spanning Tree (MST).Genetic differentiation of different lineage strains was analyzed by Analysis of Molecular Variance (AMOVA).Time of the Most Recent Common Ancestor (TMRCA) was calculated based on the Bayesian model.Results Four hundred and thirteen MTBs were divided into two major lineages,in which the Beijing lineage accounted for 56.2％ (232/413) and the Euro-American lineage for 43.8％ (181/413).There was no significant difference of population distribution between the two lineages (P＞0.05).The N-J tree of Beijing lineage MTB presented distinctly "star-like" and 72.4％ strains were grouped to one clonal complex in MST.The Euro-American lineages MTB presented "branch-like" in N-J tree and were grouped into multiple clonal complexes in MST.There was significant genetic differentiation in Beijing lineage MTBs between Chongqing and Sichuan (FST=0.018 91,P＜0.05),but not in the Euro-American lineage MTB (FST=0.005 19,P＞0.05).TMRCA of the largest clonal complex in Euro-American lineage MTB appeared to be 723 (95％ CI:517-946) years.Conclusion Both Beijing lineage and Euro-American lineage MTBs were competitively prevalent in the Sichuan basin.There was some difference noticed between the two lineages referring to genetic differentiation.The invasion of Euro-American lineages MTB to the basin area might be associated with a war occurred in this area about 720 years ago.

Preparation and bioactivity evaluation of streptavidin-tagged human interferon- inducible T cell alpha chemoattractant bifunctional fusion protein / 南方医科大学学报

<p><b>OBJECTIVE</b>To prepare streptavidin-tagged human interferon-inducible T cell alpha chemoattractant bifunctional fusion proteins (SA/hI-TAC) and evaluate its biological activity.</p><p><b>METHODS</b>pET24a-SA-hI-TAC/pET21a-hI-TAC-SA plasmids were constructed and expressed in BL21. SA-hI-TAC and hI-TAC-SA fusion proteins were purified by Ni-NTA affinity chromatography, refolded by dialysis and identified by Western blotting. The bifunctionality of the fusion proteins (biotin-binding function and hI-TAC activity) was analyzed by flow cytometry and lymphocyte chemotaxis experiment, respectively.</p><p><b>RESULTS</b>SA-hI-TAC/hI-TAC-SA fusion proteins were expressed at about 12% and 25% of the total bacterial protein, respectively. The two fusion proteins had a purity of about 85% and 90% after purification, and their purity reached 98% after purification with S-100 gel filtration chromatography. Both of the fusion proteins were efficiently immobilized on the surface of biotinylated mouse bladder cancer MB49 cells (91.3% for SA-hI-TAC and 98.8% for hI-TAC-SA). SA/hI-TAC induced lymphocyte chemotaxis in a dose-dependent manner, and hI-TAC-SA showed a stronger chemotactic effect than SA-hI-TAC.</p><p><b>CONCLUSIONS</b>We successfully obtained SA/hI-TAC bifunctional fusion proteins, which may potentially be used in local treatment of tumor and as a tumor vaccine.</p>

Characterizaiton of virus-like particles prepared by Bac-to-Bac system co-expressing HA and M1 ;protein of highly pathogenic avian influenza H5N1 / 中华微生物学和免疫学杂志

Objective To express and characterize the virus-like particles( VLPs) of H5 subtype containing of hemagglutinin ( HA ) and matrix 1 ( M1 ) protein by using Baculovirus-insect cells .Methods Full length genes encoding HA protein from the A/Indonesia/05/2005(H5N1) strain and the M1 protein from the A/Anhui/01/2005 ( H5N1 ) strain were cloned into a baculovirus expression vector to construct pFBD-M1-HA.The expression of HA and M1 proteins were detected by Western blot and indirect immunoflu-orescence after the transfection of Spodoptra frugiperda (Sf9) insect cells with recombinant baculovirus.Pu-rified VLPs were analyzed by SDS-PAGE and visualized with transmission electron microscope.The biologi-cal activity of purified VLPs was detected by hemagglutination test.Results The HA and M1 proteins of H5 subtype expressed by baculovirus-insect cells could be self-assembled into the functional mature VLPs.The hemagglutination titer of VLPs was as high as 1024 HAU/50μl.Conclusion The H5 subtype VLPs as pre-pared in this study would pave a way for the development of a candidate recombinant A ( H5) vaccine.

Development of a time-resolved fluorescence immunoassay for rapid determinat-ion of levels of cardiac troponin Ⅰantigen in human serum / 中国免疫学杂志

To establish a method to detect cardiac troponin I by using time-resolved fluoroimmunoassay ( TRFIA) and apply to the clinic.Methods:The assay were measured by TRIFA and double antibody sandwich method .Standard protocols were evaluated with the standard curve , the limit of detection , stability, precision and cross reaction .Healthy reference populations and clinical serum specimens were measured to established the reference interval and evaluated the perspective of the clinical application . Results:The standard curve was Y=7485 .878+1400.924 X with a correlation coefficient of 0.999.The limit of detection was 0.052 ng/ml.The intra-and inter-assay coefficients of variation ( CV) were all 0.05 ).There was significant difference in statistics compared before and after treatment with AMI ( P<0.001 ) .Conclusion: The TRFIA method for detecting cTnI achieves clinical application standards and may be used for the diagnosis and serosurveillance of acute myocardial infarction patients.

Comparison of two types of cell cultures for preparation of sTNFRII-gAD fusion protein / 生物工程学报

In this study we used two types of cell cultures, i.e., anchorage-dependent basket and full suspension batch cultures of sTNFRII-gAD-expressing CHO cells in the CelliGen 310 bioreactor (7.5 L) to compare their yields in order to optimize the culturing conditions for efficient expression of sTNFRII-gAD fusion protein consisting of soluble tumor necrosis factor receptor II and globular domain of adiponectin. The anchorage-dependent basket culture was performed in 4L 10% serum-containing medium with the final inoculating concentration of 3 x 10(5) to 4 x 10(5) cells/mL of sTNFRII-gAD-expressing CHO cells for 3 days, and then switched to 4 L serum-free LK021 medium to continue the culture for 4 days. The full suspension batch culture was carried out in the 4 L serum-free LK021 medium with the final inoculating concentration of 3 x 10(5) to 4 x 10(5) cells/mL of sTNFRII-gAD-expressing CHO cells for 7 days. The culturing conditions were monitored in real-time to maintain pH and dissolved oxygen stability through the whole process. The supernatants were collected by centrifuge, and the protein was concentrated through Pellicon flow ultrafiltration system and then purified by DEAE anion exchange. The results showed that the yields of sTNFRII-gAD fusion protein were 8.0 mg/L with 95% purity and 7.5 mg/L with 98% purity in the anchorage-dependent basket and the full suspension batch cultures, respectively. The study provided the framework for the pilot production of sTNFRII-gAD fusion protein.

Generation of streptavidin-tagged human-granulocyte macrophage colony-stimulating factor fusion proteins / 南方医科大学学报

<p><b>OBJECTIVE</b>To obtain streptavidin-tagged human granulocyte-macrophage colony-stimulating factor (SA/hGM-CSF) fusion protein and evaluate its bioactivity .</p><p><b>METHODS</b>PET24a-6His-SA-L-hGM-CSF and PET24a-hGM-CSF-L-SA-6His plasmids were constructed and expressed in Rosetta (DE3) host bacteria to generate the fusion proteins. The two fusion proteins were refolded by gradient dialysis after Ni-NTA affinity chromatography and finally purified using DEAE-sepharose FF anion exchange chromatography. MTT method was used to evaluate the effect of SA/hGM-CSF fusion proteins in inducing the proliferation of human erythroleukemia cells (TF-1). The efficiency of the fusion proteins for surface modification of biotinylated MB49 tumor cells was evaluated by flow cytometry.</p><p><b>RESULTS</b>The recombinant fusion proteins SA-hGM-CSF and hGM-CSF-SA were highly expressed in Rosetta (DE3) at about 20% of the total bacterial proteins, with a purity of about 96% after purification. The two fusion proteins exhibited bifunctional activities, namely the pro-proliferation effect on human erythroleukemia cells (TF-1) and SA-mediated high-affinity binding to biotinylated cell surfaces (with an anchoring modified rate of about 99%).</p><p><b>CONCLUSION</b>SA/hGM-CSF bi-fusion proteins obtained in this study lays the groundwork for the development of cancer cell vaccines with surface modification by hGM-CSF.</p>

Prokaryotic expression, purification, and identification of recombinant human IL-11 protein / 生物医学工程学杂志

A DNA fragment encoding recombinant human interleukin 11 (hrIL-11) was obtained by PCR from previously constructed pET24a-hrIL-11 plasmid. Then pET21a-hrIL-11 expression vector was constructed routinely and transformed into BL-21(DE3). By the induction of Isopropyl-1-thio-beta-D-galactoside (IPTG), hrIL-11 protein was highly expressed at about 20% of the total bacterial proteins and was identified by Western blot. After purification with Ni-NTA affinity chromatography and refolding with renaturation buffer, the purity of the target hrIL-11 protein reached 95% and its biology activity was 1 x 10(6) IU/mg, determined by stimulating the proliferation of T1165, which facilitates further researches into effects of IL-11 on platelet proliferation and other function.