AIM: To investigate the CdTe quantum dots coated with MPA and explore its biocompatibility with living cells. METHODS: CdTe quantum dots coated with MPA were prepared in aqueous phase and MPA CdTe QDs were Characterized with TEM, fluorospectrophotometer and ultraviolet spectrophotometer. QDs were Modified with with avidin, purified and prepared as flurescent probe. LSCM was used to observe the expression of MHC Ⅱ antigen on PMφ cells, which was labeled by QDs. Cell culture and MTT assays were used to determine the biocompatibility of MPA coated CdTe quantum dots with the B-16 cells as target cells. RESULTS: The particle diameter of CdTe quantum dots prepared in aqueous phase was well distributed. They had good photological performance and greater stability after coated with MPA. MHC Ⅱ antigen on PMφ was labeled with the QDs-Avidin fluorescent probe showed great fluorescence intensity, which was easy to be detected by fluorescence microscope and LSCM. MPA CdTe QDs showed cytotoxicity when its density was very high, but they showed little cytotoxicity during the normal use of influence label density limit. CONCLUSION: MPA CdTe QDs can be used as new fluorescent lable as they are of even size, not easy to bleach or quench, have good photological performance and stability and good biocompatibility.

AIM: To prepare a soluble hemangiopoietin(HAPO) protein and to construct pET22b(+) expression vector, to obtain pure recombinant HAPO protein and to measure its bioactivity. METHODS: HAPO cDNA was amplified using RT-PCR method from a commercial human fetal liver cDNA library. The resulting product was cloned into pET22b(+) vector and transformed into E.coli BL21(DE3). The recombinant protein was isolated and purified by Ni~(2+)-NTA chelating resin and the chromatographies of SP Sepharose FF. The adhesion of human umbilical vein endothelial cells (HUVEC) were measured by adhesion assay. RESULTS: HAPO gene with a reading frame of 897 bp was successfully cloned from human fetal liver cDNA library, the expressed pET22b(+)-HAPO fused protein existed in a soluble form, with the yield above 10% total bacterial protein and its purity achieved above 80%. The activity assay showed that the treatment of HAPO enhanced total adherence of HUVEC in a concentration-dependent manner. CONCLUSION: HAPO protein can be expressed in a soluble form. HAPO may facilitate the homing of hematopoietic stem/progenitor cells in vitro.

AIM: To clone EBV-LMP2A gene, construct and identify the recombinant retroviral vector and stable cell strains expressing EBV LMP2A. METHODS: The full-length EBV LMP2A gene was generated by RT-PCR amplification from B95.8 cells which contain complement nucleotide sequence of EBV LMP2A gene. The gene was ligated to T-vector and sequenced to construct retroviral vector consisting with LMP2A. To produce retroviral virus, packing cells, 293T cells were co-transfected with recombinant retroviral expression vector pGEZ-LMP2A and two auxiliary viral vectors pHIT456 and pHIT60 by lipofectAMINE2000. Viral titration was performed according to the instructions of the manufacturer. To establish L929 cell line stable expressing LMP2A, L929 cells were infected with recombinant retrovirus three times and selected by Zeocine. The Zeocine-resistant clones (L929/LMP2A) were screened for LMP2A expression by RT-PCR and Western blot. RESULTS: The recombinant retrovirus vector carrying LMP2A gene was constructed successfully. Transfection yield a titer of 5×10~8 infectious particles/L. The infected L929 cells were selected by Zeocine. Results of RT-PCR and Western blot indicated that L929 transgenetic cells could stably express EBV-LMP2A. CONCLUSION: The L929 cell line stably expressing LMP2A provides suitability for extraction of the LMP2A protein and preparations of the vaccine for the therapy of EBV-associated diseases.

AIM: To investigate the alteration and its significance of T help 17 cells(Th17) in patients with chronic lymphocytic thyroiditis(CLT). METHODS: Patients were divided into 3 groups: CLT patients with euthyroidism (n = 15), CLT patients with hypothyroidism (n = 30) and healthy control group(n = 20). The ratio of Th17 lymphocytes subpopulations in the preipheral blood were evaluated by technique of flow cytometry. Production of thyroid autoantibody (TPO-Ab, TG-Ab) were measured by electro-chemiluminescence immunoassay (ECLIA). RESULTS: Compared with the healthy control group, in CLT group: The frequencies of Th17 in peripheral blood were found to be significantly higher in patients with CLT than healthy control group (P < 0.01); Production of TPO-Ab and TG-Ab markedly increased in CLT patients than healthy control group (P < 0.01). There was significant correlation between the positive expression of thyroid autoantibody and the changes of Th17 subpopulations (r=0.50, r=0.43 respectively; P < 0.01). CONCLUSION: The frequencies of Th17 cell increased in patients with CLT which may suggest a potential role for Th17 in the progression and happen of CLT.

Aim To explore the ethanol-induced apoptosis effect on hepatocellular carcinoma(HCC) cells and its relationship to the expression of apoptosis associated genes, bax and bcl-2. Methods The cytotoxic effect of 20～ 100 mL/ L ethanol on HCC cell line HCC-9204 was tested by thiazolyl-blue (MTT) assay. Then apoptosis of HCC-9204 cells was induced with 60 mL/ L of ethanol for 6 h. The morphological change, DNA breakage and the change of DNA content of different cell cycles of the apoptotic cells were detected by May-Grunwald Giemsa(MGG) staining, and terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) assay and flow cytometer respectively. The changes of expression level of Bax and Bcl-2 proteins were detected by immunocytochemical staining and image analysis. Results The higher the concentration of ethanol was, the stronger the cytotoxic effect on HCC-9204 cells was. 60 mL/ L of ethanol could lead to obviously morphological apoptotic changes of HCC-9204 cells, and majority of the cells were TUNEL positive by TUNEL labeling assay. Typical apoptotic sub G1 peak was observed by flow cytometer. The level of Bax protein expression increased significantly after induced with 60 mL/ L of ethanol for 6 h, no expression of Bcl 2 were found before and after induced with ethanol. Conclusion Low dose of ethanol can induce apoptosis of HCC-9204 cells obviously, and occurance of the apoptosis is related to the increase of the level of Bax protein expression.

AIM: To study the effect and mechanism of BCG on human nature killer cells. METHODS: PBMC or purified NK cells were isolated from normal human peripheral blood with negative anti-Mycobacterium tuberculosis antibody and cultured with BCG, IL-12, BCG plus IL-12 and BCG plus anti-IL-12Rβ1 mAb (2B10), respectively. The levels of IFN-γ and IL-12p40 in the culture supernatants were measured by ELISA. The frequency of IFN-γ and granzyme B producing cells were analyzed by ELISpot. The cytolytic activity was detected by MTT reduction assay. The surface expression of IL-12Rβ1 on NK cells was detected by flow cytometry. RESULTS: BCG significantly induced IFN-γ production by PBMC in a dose-dependent manner. When PBMC was stimulated with BCG, the frequency of granzyme B producing cells was higher than that in unstimulated PBMC (P<0.05). BCG enhanced the cytotoxic activity of PBMC. BCG alone didn' t induce IFN-γ production by purified NK cells, but it can augment IL-12-induced IFN-γ production by purified NK cells. The cytotoxic activities of BCG-stimulated and unstimulated purified NK cells were not significantly different (P>0.05). BCG induced IL-12 production by PBMC in a dose-dependent manner and enhanced IL-12Rβ1 expression on different subsets of NK cells. Blocking the effect of IL-12 by anti-IL-12Rβ1 mAb (2B10) inhibited BCG-induced IFN-γ production and granzyme B releasing by PBMC. CONCLUSION: BCG can indirectly promote biologic activity of NK cells and the production of endogenous IL-12 combined with up-regulation IL-12Rβ1 expression on the surface of NK cells is a part of the mechanisms of IL-12 on human NK cells.

AIM: To analyze the capability of cytomegaIovirus (CMV)-infected human embryonic lung fibroblasts (HELFs) to induce immune response. METHODS: HELFs were infected with cytomegalovirus and stained with antibody against HLA-A2 molecular, the expression of HLA-A2 was detected by FCM. The infected HELFs were incubated with individual pp65 peptide NLVPMVATV. While the uninfected and unloaded infected HELFs served as control respectively. After PBMC was added to the differently treated HELFs and incubated, the immune response was measured with IFN-γ release as readout. RESULTS: The expression of HLA-A molecular on infected fibroblasts diminished markedly compared with that on the uninfected. The peptides expressed on the infected HELFs together with those pulsed externally induced a stronger response than the infected HELFs alone. CONCLUSION: Although CMV can downregulate the expression of MHC Ⅰ on the infected cells, it can not decrease the capacity of cells to present peptides loaded externally, and therefore still induce immune response to some extent.

AIM: To explore the different effect and mechanism of arsenic sulfide on telemorase activity and hTERT-mRNA expression in CML cell lines-KS62 and APL cell lines-NB4. METHODS: Telomerase activity was determined by polymerase chain reaction enzyme-linked immunoassay (PCR-ELISA). The expression of hTERT-mRNA was analyzed by semi-quantitative RT-PCR. Flow cytometry was used to analyze the cell cycle and apoptosis. RESULTS: 0.15-0.6 mg/L arsenic sulfide (72 h)can induce apoptosis and inhibit telomerase activity and hTERT-mRNA expression in NB4 cell. The concentration of arsenic sulfide with the same effect on K562 cell was 0.3-3 mg/U 0.3 mg/L arsenic sulfide (72 h) can cause the proportion of the NB4 cell in G2/M phase increased, but for K562 cell, The concentration of arsenic sulfide was 1.5 mg/L. CONCLUSION: Telomerase system may be one.of the pathway for arsenic sulfide inducing apoptosis of NB4 and K562 cell; G2/M phrase arrest may have correlation with decrease of telomerase activity; The sensitivity of NB4 and K562 call for arsenic sulfide is different, the mechanism of it need to study more.

im To study the structure-function relationship of hTNFα . Methods We compared the cytotoxicity, receptor binding ability and toxicity in animal body of wild type(wt)hTNFα with its mutants including R2K-, N30S-, R32W-, L157F-hTNFα , and two multi-site mutants(R32W-L157F-hTNFα and R2K-N30S-R32W-L157F-hTNFα ). Results We found that the two multi-site mutants remained similar cytotoxicity to several human tumor cell lines as wild type hTNFα . However, their cytotoxicity to L929 cells were decreased sharply as compared with those of wt hTNFα . The two multi-site hTNFα mutants had lower binding activity with hTR75 than hTR55. We also found that compared with the wild type, the LD50 of the mutant R32W-L157F-hTNFα was decreased about 300 fold and the dose of mutant R2K-N30S-R32W-L157F-hTNFα resulted in 30％ death was 700 folds lower than LD50 of wt hTNFα . To certify the systematic toxicity of the mutant R2K-N30S-R32W-L157F-hTNFα , we assayed its toxicity to monkeys and found that its systematic toxicity was lower than that of wt hTNFα. Conclusion A 4-site mutants(R2k-N30S-R32W-L157F-hTNFα )of hTNFα is obtained, which the mutant may possess potential application value in clinical therapy.

AIM: DNA vaccines expressing protective domain of surface protective antigen A（spaA）of Erysipelothrix rhusiopathiae have been relatively ineffective at generating high-titer, long-lasting, neutralizing antibodies in murine models. METHODS: This paper report using a DNA vaccine expressing a fusion of the spaA protein and various elements, such as a secretion leader sequence from the highly expressed human gene encoding α1-antitrypsin (AAT), a highly soluble and stably folded domain from the rat cartilage oligomerization matrix protein (COMP), and three copies of the complement component, C3d3, to enhance the titers of neutralizing spaＡ-specific antibody. RESULTS: Analysis of titers of the antibody raised in vaccinated mice at different time points indicated that immunizations with the DNA expressing pcDNA3-AAT-COMP-spaAN-3C3d((pcD-ACSC)) had higher titers than pcDNA3-spaA_N(pcD-S) at weeks 4. Furthermore, the immune protective efficacy of the spaA-chimeras was demonstrated by lethal challenge with a virulent homologous strain 1249 against immunized mice. CONCLUSION: These results suggest that using a plasmid vector containing a strong heterologous signal sequence that mediate efficient antigen secretion in vivo and a fused piece of sequence improving antigens solubility, as well as C3d3, genetic adjuvant, could enhance the antibody responses level. This approach might be an efficient way to improve the antibody level of spaA_N DNA vaccination.