Biomedical subjects

Bo-Quan Jin

Publications and source records attributed to Bo-Quan Jin.

At least 19 recordsLinked to original sources

PubMed2006

CD molecules 2006--human cell differentiation molecules.

The Human Leucocyte Differentiation Antigens Workshops (HLDA) have since 1984 provided a forum for the characterization and study of leucocyte surface molecules and antibodies against them. HLDA devised the CD nomenclature, which is sanctioned by IUIS. The HLDA Council reviewed and modified the objectives of HLDA in 2004, and changed the name of the organization to Human Cell Differentiation Molecules (HCDM) to reflect the broader objectives. Workshop studies under the HCDM banner proceeded during 2005 and early 2006, culminating in a meeting in May 2006. At that meeting the Council, acting as Nomenclature Committee, approved a number of new CD designations and changes to some pre-existing CD designations, which are summarized in this report.

Antigens, CD↗

PubMed2006

Identification and characterization of the CD226 gene promoter.

CD226 is one of the main activating receptors on natural killer cells, and it can induce cytotoxicity to target cells through interaction with its ligands CD155 or CD112. CD226 is also involved in T cell differentiation, activation, and cytotoxicity. The expression of CD226 on natural killer cells and T cells can be regulated by cytokines and chemical stimuli; however, the mechanism of the regulation of the CD226 gene is still unknown. In this study, we have identified two promoters in the human CD226 gene named P1 and P2, which are located at -810 to -287 bp and +33 to +213 bp, respectively, and a negative regulation element between P1 and P2. Both P1 and P2 can be regulated by phorbol ester (12-O-tetradecanoylphorbol-13-acetate) and calcium ionophore (A23187). Bioinformatics analysis shows that, within this CD226 gene region, there are putative binding sites for transcription factors AP-1, Sp1, PEA3, and Ets-1. We have found that transcription factor activating protein-1 (AP-1) can up-regulate CD226 promoters P1 and P2 in human hepatocarcinoma cells, a hepatocarcinoma cell line with low expression of endogenous AP-1 and Ets-1. Interestingly, the transcription factor Ets-1 promotes AP-1-induced P2 activity but inhibits AP-1-induced P1 activity for which a 10-bp AP-1/Ets-1 composite site (CCTTCCTTCC) in P1 may be responsible.

Antigens, Differentiation, T-Lymphocyte↗

PubMed2006

Dynamic changes of apoptosis-inducing ligands and Th1/Th2 like subpopulations in Hantaan virus-induced hemorrhagic fever with renal syndrome.

The expression of the apoptosis-inducing ligands, TNF-alpha, FasL and TRAIL on peripheral blood mononuclear cells (PBMC) and the levels of their soluble form (TNF-alpha, sFasL and sTRAIL) in plasma from 40 hemorrhagic fever with renal syndrome (HFRS) patients as well as 26 healthy blood donors were determined by flow cytometry (FCM) analysis and sandwich ELISA, respectively. The status of Th1, Th2, Tc1 and Tc2 subsets in PBMC was evaluated by intracellular cytokine staining and FCM. Compared to controls, the expression of membrane bound FasL and TRAIL was up-regulated on surface of PBMC isolated from the HFRS patients, particularly on CD8+ T lymphocytes. The levels of TNF-alpha, sFasL and sTRAIL in plasma from the HFRS patients in the acute phase increase 4.7-fold, 6.0-fold and 1.8-fold, respectively, over those from the healthy donors. The percentage of Th1, Tc1 and Tc2 subsets in PBMC from the patients also increased significantly compared with those from healthy donors. These results indicate that dynamic changes occurred in both the membrane bound and soluble forms of apoptosis-inducing ligands (FasL, TRAIL and TNF-alpha) and proportions of Th1 and CTL in HFRS patients increased. Both factors may play an important role in the etiology of Hantaan virus infection in humans.

Adolescent↗

PubMed2005

Characterisation of monoclonal antibodies to the TNF and TNF receptor families.

Tumour necrosis factor (TNF) family ligands and their corresponding receptors play important roles in the immune system and are involved in immune regulation such as lymphoid development, cell proliferation, differentiation, activation and death. Antibodies against these ligands and receptors together with Fc-fusion proteins, have been particularly useful as immunological tools in addressing the underlying involvement of these proteins in these contexts and furthermore, have given us hope in using them as potential therapeutic agents. Over last few years, there have been many additions to these ever-growing TNF family ligands and their receptors. Here, we have generated and characterised a set of monoclonal antibodies, together with mAbs from the HLDA workshop, against DcR1, DcR2, DR4, DR5, TRAIL, APRIL, BAFF, BAFF-R, BCMA, and TACI, which may be useful in phenotypic and functional studies of the role of TNF and TNF receptor family in immune function and regulation in relation to health and disease.

Animals↗

PubMed2005

Expression pattern of epithelial cell adhesion molecule on normal and malignant colon tissues.

AIM: To investigate the expression pattern of epithelial cell adhesion molecule (Ep-CAM) on normal and malignant colon tissues to evaluate its diagnostic and therapeutic significance. METHODS: cDNA encoding Ep-CAM extracellular domain was cloned by reverse transcription-polymerase chain reaction (RT-PCR) from excised malignant colon tissues and inserted into a glutathione S-transferase (GST)-tagged vector. Ep-CAM-GST fusion protein was induced by isopropyl-beta-D-thiogalactopyranoside (IPTG) and purified with glutathione-sepharose. The Ep-CAM-GST fusion protein was mixed with Freund's adjuvant and Balb/c mice were immunized with it. Sp2/0 myeloma cells were fused with the spleen cells of the immunized mice. After having selected by indirect ELISA, the anti-Ep-CAM monoclonal antibodies (MAbs) were generated and the corresponding ascites were obtained. Finally, the human colon carcinoma tissue array prepared from seventy individual patients was stained with the anti-Ep-CAM MAbs. RESULTS: The isolated Ep-CAM cDNA sequence was identical to the data in GenBank. The expressed fusion protein was almost soluble and had a molecular weight (MW) of 53 ku. Four MAbs against Ep-CAM were obtained and designated as FMU-Ep1, FMU-Ep2, FMU-Ep3 and FMU-Ep4 respectively. Among them, FMU-Ep4 could recognize the natural Ep-CAM on Colo205 and SW480 cells, and all of them could be used for immunohistochemical staining of tissue sections. It was found that Ep-CAM was distributed differently in normal and various malignant colon tissues, including squamous cell carcinoma, signet-ring cell carcinoma and adenocarcinoma. In normal colon gland epithelia, Ep-CAM antigen was mainly distributed on the basolateral membrane and in the region between the basolateral membrane and the cytoplastic part near the nuclei, whereas the expression pattern of colon malignancies was mainly on the whole surface of epithelia and the expression was much higher than the normal colon tissues. The staining pattern of tissue array showed in adenocarcinoma and papillary adenocarcinoma, and the expression of Ep-CAM was increased from grade I to grade III. CONCLUSION: MAbs against Ep-CAM might be useful for research on the structure and function of Ep-CAM and may have diagnostic and therapeutic value to various colon carcinomas.

Animals↗

PubMed2005

[Apoptosis-inducing ligand TRAIL can be recruited to lipid rafts].

AIM: To investigate the relationship between tumor necrosis factor-related apoptosis-inducing ligand(TRAIL) and cell membrane microdomain lipid rafts. METHODS: The expression of TRAIL on K562 cells was detected by indirect immunofluorescence staining and flow cytometry. The lipid rafts on K562 cells were detected with FITC-labeled cholera toxin B subunit (CTx-FITC) which bound to the GM1 glycosphingolipid in lipid rafts. The lipid rafts were then cross-linked with an anti-FITC mAb after binding with CTx-FITC. The localization of TRAIL on K562 cells was analyzed with rabbit anti-TRAIL antibody, Cy3-labeled goat-anti-rabbit IgG (Cy3-labeled GAR) and laser scanning confocal microscope. RESULTS: The cross-linking of lipid rafts appeared at 20 minutes, reached peak at 30 minutes, and weakened around 40 minutes. After the cells were labeled with CTx-FITC and anti-FITC mAb TRAIL was aggregated in the cross-linked lipid rafts. CONCLUSION: The anti-FITC mAb could be used for cross-linking of lipid rafts. TRAIL can be recruited to lipid rafts.

Animals↗

PubMed2004

A caspase-6 and anti-human epidermal growth factor receptor-2 (HER2) antibody chimeric molecule suppresses the growth of HER2-overexpressing tumors.

Clinical studies have suggested that human epidermal growth factor receptor-2 (HER2) provide a useful target for antitumor therapy. We previously described the generation of a chimeric HER2-targeted immunocasp-3 protein. In this study, we extend the repertoire of chimeric proapoptotic proteins with immunocasp-6, a construct that comprises a HER2-specific single-chain Ab, a single-chain Pseudomonas exotoxin A, and an active caspase-6, which can directly cleave lamin A leading to nucleus damage and inducing programmed cell death. We demonstrate that the secreted immunocasp-6 molecule selectively recognizes and induces apoptosis in HER2-overexpressing tumor cells in vitro, but not in cells with undetectable HER2. The immunocasp-6 gene was next transferred into BALB/c athymic mice bearing human breast SK-BR-3 tumors by i.m. injection of liposome-encapsulated vectors, by intratumor injection of adenoviral vectors, or by i.v. injection of PBMC modified by retroviral infection. Regardless of the method used, expression of immunocasp-6 suppressed tumor growth and prolonged animal survival significantly. Our data show that the chimeric immunocasp-6 molecule can recognize HER2-positive tumor cells, promptly attack their nucleus, and induce their apoptotic death, suggesting the potential of this strategy for the treatment of human cancers that overexpress HER2.

ADP Ribose Transferases↗

PubMed2003

[CD226 monoclonal antibody induces variation of intracytosolic free calcium level in human umbilical vein endothelial cells].

In order to study the possible mechanism of CD226 monoclonal antibody (mAb)-mediated intracellular message transduction in human umbilical vein endothelial cells (HUVECs), the influence of CD226 mAb and its cross-linking by secondary antibody (II Ab) on the concentration changes in [Ca(2+)](i) in the HUVECs under different conditions were determined by confocal laser scanning microscopy. The main results are as follows. (1) When the culture medium was balanced by Hanks Buffer, [Ca(2+)](i) in HUVECs increased slowly after stimulation by CD226 mAb, whereas [Ca(2+)](i) increase was accompanied by [Ca(2+)](o) decrease after the mAb was cross-linked by goat anti-mouse IgG. Then [Ca(2+)](i) and [Ca(2+)](o) all returned to the normal level. (2) When the culture medium was balanced by D-Hanks buffer, [Ca(2+)](i) in HUVECs showed little variation when the cells were stimulated by CD226 mAb, but [Ca(2+)](i) decreased markedly after cross-linking. (3) When HUVECs were pretreated with EGTA, there was no variation in [Ca(2+)](i) of HUVECs after CD226 mAb stimulation alone or cross-linking of the mAb. Our results suggest that stimulation by CD226 mAb and cross-linking by goat anti-mouse IgG induce the variation of [Ca(2+)](i) in HUVECs under different conditions and the variation of [Ca(2+)](i) in HUVECs may play an important role in many physiological and pathological processes.

Antibodies, Monoclonal↗

PubMed2003

Preparation and characterization of a set of monoclonal antibodies to TRAIL and TRAIL receptors DR4, DR5, DcR1, and DcR2.

The tumor necrosis factor-related apoptosis-inducing ligand (TRAIL/Apo 2L) is a novel cytotoxic ligand belonging to TNF superfamily. Among TRAIL receptors, death receptor 4 (DR4) and DR5 containing death domain (DD) in their cytoplasmic region mediate apoptosis-signaling upon TRAIL binding, while decoy receptor 1 (DcR1) and DcR2 with a truncated or non-functional DD play "decoy" role. The interaction of TRAIL and TRAIL receptors plays important roles both in immunoregulation and immune pathogenesis of some diseases. In this study, we raised hybridomas secreting monoclonal antibodies against TRAIL (FMU1.1, 1.2, 1.3), DR4 (FMU1.4), DR5 (FMU1.5, 1.6), DcR1 (FMU1.7) and DcR2 (FMU1.8, 1.9). These MAbs could be used for fluorescent staining and flow cytometry (FCM) analysis as well as immunohistochemistry (IHC). Moreover, FMU1.1, 1.3, 1.4 and 1.5 could be used as coating antibodies paring corresponding polyclonal antibodies to develop sandwich ELISAs to quantitate the soluble TRAIL (sTRAIL), sDR4 or sDR5 in serum samples respectively. In addition, cross-linking of DR4/DR5 by FMU1.4 or FMU1.5 MAbs could induce apoptosis of some DR4/DR5-expressing tumor cells. Thus, this set of monoclonal antibodies against TRAIL or TRAIL receptors may be useful in expression phenotypic and functional study of TRAIL and TRAIL receptors.

Animals↗

PubMed2003

Localization of TRAIL/TRAILR in fetal pancreas.

AIM: To observe the localization of TRAIL/TRAIR (DR4, DR5, DcR1, DcR2) in the fetal pancreas. METHODS: Fetal pancreas of 32 weeks of pregnancy were obtained from induced abortions, embedded in paraffin, and 4-microm sections were prepared. The localization of TRAIL/TRAILR in fetal pancreas was investigated by fluorescence immunohistochemical method combined with laser scanning confocal microscopy. RESULTS: TRAIL immunoreactive cells were mainly located on the periphery of the pancreas islets. There were a few DcR1 and DcR2 positive cells whereas there were no immunoreactive cells of DR4 and DR5 in the pancreas islets. In the acini and the ducts of the exocrine pancreas there were no TRAIL/TRAILR immunoreactive cells. CONCLUSION: This study not only describes the distribution of TRAIL/TRAILR in the fetal pancreas, but also provides a morphological basis for deducing the function of TRAIL/TRAILR in pancreas, suggesting that in normal pancreatic islets, the pancreatic cells are resistant towards apoptosis too.

Apoptosis Regulatory Proteins↗

PubMed2003

Selection and identification of mimic epitopes for gastric cancer-associated antigen MG7 Ag.

Phage display technology is now well established as an important experimental approach in designing new reagents for diagnosis of diseases and development of novel vaccines. Aiming at identifying possible immunogenic mimotopes of gastric cancer-associated antigen, we used a monoclonal antibody against gastric cancer, named monoclonal antibody MG7, to screen two phage-displayed nanopeptide libraries. All selected phages were used to immunize BALB/c mice separately. By immunohistochemical staining the tissue sections with the immunized mice sera, we identified one phage that induced gastric cancer-specific antibody response. Consistent with our reported results before, we demonstrate that specific immunogenic epitopes can be isolated by screening phage-displayed library even when natural antigens are not readily available.

Animals↗

PubMed2003

[Expression and regulation of a novel soluble adhesive molecule sCD226 on human endothelial cells].

AIM: To explore the expression and regulation of a novel soluble adhesive molecule sCD226 on HUVECs. METHODS: The contents of sCD226 and NO in culture supernatant of LPS activated human umbilical vein endothelial cells (HUVECs) were detected by ELISA and Greiss method respectively, and linear correlativity of contents between sCD226 and NO was analysed. The influence of anti-TNF-alpha mAb and iNOS inhibitor on LPS-induced sCD226 production was observed by ELISA. RESULTS: (1)LPS might markedly stimulate sCD226 production from HUVECs in a dose- and time-dependent manner. The amount of sCD226 came to 188.5 microg/L when endothelial cells were stimulated by 100 mg/L LPS for 3 days. (2)The production of NO and sCD226 showed linear correlation when HUVECs were stimulated by 100 mg/L LPS.(3)LPS-induced sCD226 production in HUVECs was inhibited significantly by anti-TNF-alpha mAb and iNOS inhibitor. CONCLUSION: LPS-activated-HUVECs can secret sCD226 and the generation of sCD226 is closely correlated with the production of NO and TNF-alpha.

Adhesives↗

PubMed2003

[Cloning, prokaryotic expression of LAIR and identification of their immunological reactivities].

AIM: To clone and express the leukocyte-associated immunoglobulin-like receptor (LAIR) and to identify the immune reactivity of LAIR-2 to anti-LAIR-1 specific monoclonal antibodies(mAb). METHODS: Genes encoding LAIR-1 and LAIR-2 were cloned by RT-PCR from human peripheral blood mononuclear cells(PBMC) and two leukemia cell lines Jurkat and HL-60. The extracellular region gene of LAIR1 and LAIR-2 were inserted into vector pGEX-4T-3 expressing GST fusion protein, expressed on IPTG induction and purified through glutathione-sepharose 4B column. The immunological reactivity of expressed LAIR-2 to anti-LAIR-1 mAb was identified by indirect ELISA. RESULTS: LAIR-1 and LAIR-2 cDNAs had been cloned and expressed. Five new LAIR-1 cDNA isoforms were cloned. Among them, two isoforms from HL-60 included LAIR-1 open reading frames (ORF) and three isoforms from Jurkat were LAIR-1 cDNA segments. The LAIR-1 and LAIR-2 showed different immunological reactivities. CONCLUSION: The transcription, processing after transcription and expression of LAIRs may be related to disparities in individuals and disease status. The difference in immunological reactivity may be involved in their structure.

Cloning, Molecular↗

PubMed2003

[Preparation and characterization of monoclonal antibodies against human transmembrane activator and calcium modulator and cyclophilin ligand interactor].

AIM: To prepare monoclonal antibodies against human TACI and study the distribution of TACI on peripheral blood nuclear cells(PBMCs). METHODS: Murine mAbs were prepared by hybridoma technique. The distribution of TACI on PBMCs were identified by immunofluorescence staining, FCM analysis as well as immunohistochemical staining. RESULTS: Two hybridoma cell lines secreting mAbs against TACI were obtained. The titers of ascitic mAbs was 10(-7) and their Ig subclasses were IgG1. Both could recognize natural TACI on T cells. In the PHA activated models, TACI was expressed mainly on activated CD4(+) T cells. CONCLUSION: Two mAbs can recognize natural TACI, which will be of greater value in research on the structure and functions of TACI.

Animals↗

PubMed2003

[Preparation, characterization and application of monoclonal antibodies to Fc fragment of Ig fusion protein].

AIM: To prepare and characterize mAb to Fc fragment of Ig fusion protein, and to establish sandwich ELISA for detecting Ig fusion proteins and affinity chromatography method for Ig fusion protein purification. METHODS: hBCMA-Ig was used as antigen to immune BALB/c mice. The lymphocyte hybridoma technique was used to establish hybridoma cell lines stably secreting anti-Fc mAb. ELISA was employed to detect the isotype, epitopes, and species specificity of mAbs. Western blot was used to assess the reactivity between anti-Fc mAbs and denatured Ig fusion protein. LAIR1-Ig fusion protein was purified through affinity column anti-Fc mAb cross-linked to Sepharose 4B. RESULTS: Seven hybridoma cell lines(FMUFc1-FMUFc7) were acquired. A sandwich ELISA was successfully established using FMUFc4 as coating mAb and FMUFc5 as enzyme-labeled mAb. FMUFc6 could be used for Western blot. LAIR1-Ig fusion protein was effectively purified through FMUFc5-Sepharose affinity chromatography column. CONCLUSION: mAb against Fc fragment of Ig fusion protein has been prepared successfully, and methods to detect and purify Ig fusion protein are established. These mAbs provide useful tool for further application of Ig fusion protein.

Animals↗

PubMed2003

[Establishment of a sandwich ELISA for detecting serum sTRAIL and its application].

AIM: To establish quantitative ELISA for detecting souble TRAIL and to evaluate its clinical application. METHODS: The mAb FMU1.1 against TRAIL was used as coating antibody, and the rabbit polyclonal antibody to TRAIL as a sandwich antibody. The serum sTRAIL levels of nine patients with hemorrhagic fever with renal syndrome and forty psoriasis patients were measured by this method. RESUITS: Sandwich ELISA was established by combination of mAb and pAb. The sensitivity of the ELISA was 0.08 microg/L. The increased levels of serum sTRAIL were found in three cases out of nine HFRS patients and eight cases out of forty psoriasis patients. CONCLUSION: A sandwich ELISA is developed, which provide an useful tool judging the patients condition, curable effect and prognosis of some related diseases.

Animals↗

PubMed2003

[Development and preliminary application of a double mAb sandwich ELISA for detecting soluble CD226].

AIM: To develop a double mAb sandwich ELISA for detecting sCD226 and apply it to clinical specimens. METHODS: The optimal concentrations of coating mAb and HRP-mAb, and the optimal diluents were determined. A double mAb sandwich ELISA then was established. The specificity, sentivity and stability of the method were identified. And clinical specimens were detected by this method. RESULTS: The optimal concentrations of coating mAb LeoA1 and HRP-mAb FMU3 were 2.5 mg/L and 1:400, respectively, and the optimal diluents for standard antigen and HRP-mAb were 1 g/L BSA 1 mL/L Tween20-PBS and 30 g/L PEG-PBS.The ELISA achieved satisfactory results in respect to specificity (no cross-reaction to human IgG, in block test blocking effect was does-dependent), sensitivity (the detected threshold was 110 ng/L) and stability (CV<10.2%). Statistical analysis showed that the serum sCD226 level in patients with rheumatoid arthritis (RA) was significantly higher than that in healthy adults. CONCLUSION: A double mAb sandwich ELISA with high specifity, and relative sensitivity for detection of sCD226 has been developed. It is shown to be an applicable method of detecting sCD226 in clinical specimens.

Antibodies, Monoclonal↗

PubMed2003

[Eukaryotic expression and application of human CD226 Ig fusion protein containing 3C protease-restricted site].

AIM: To construct, express and characterize the eukaryotic expression vector of encoding human CD226 (PTA1) extracellular region Ig fusion protein gene containing 3C protease-restricted site. METHODS: The gene fragment encoding extracellular region of human CD226 was cloned into the eukaryotic expression vector p-3C-Ig containing 3C protease-restricted site and human Ig Fc fragment gene. After sequencing, the vector was transfected into COS7 cells, and the expressed molecule was purified by affinity chromatography. Finally, the product was characterized by immunofluorescent staining and 3C protease digestion. RESULTS: After expression and purification, the Ig fusion protein could bind effectively to the CD226 ligand expressed on ECV304 cells. The Fc fragment could also be cut off by 3C protease, so that the CD226 extracellular fragment was obtained. CONCLUSION: The extracellular region of human CD226 Ig fusion protein with 3C protease-restricted site is expressed successfully in COS-7 cells, which lays the foundation for the structural and functional study of this molecule.

Animals↗