Biomedical subjects

Ping Zou

Publications and source records attributed to Ping Zou.

99 records · Page 6Linked to original sources

PubMed2002

[A comparison between immunophenotypes of lymphoid cells from human umbilical cord blood and bone marrow and its significance].

To compare the expression of CD antigens on immune cells from umbilical cord blood (UCB) and bone marrow (BM) and analyze its clinical significance, the phenotypes of lymphoid cells and nucleated cells from 38 UCB and 10 BM samples were investigated by flow cytometry with double labeling monoclonal antibodies. The results showed that the immature lymphocytes (CD3(-) CD4(+)) were detected in UCB and higher than those in BM; cytotoxic T lymphocytes (CD3(+) CD16(+) CD56(+)) in UCB were significantly lower than those in BM. NK cells (CD3(-) CD16(+) CD56(+)) in UCB were higher than those in BM. The ratio of CD34(+) cells in nucleated cells of UCB was similar to that of BM, however, both the contents of myeloid (CD34(+) CD13(+) and CD34(+) HLA-DR(+)) and lymphoid (CD34(+) CD19(+)) progenitor cells in UCB were lower than those in BM. It is concluded that the immune cells in UCB possess immaturity, which might lead to mild GVHD after UCB transplantation. It is inferred from the higher ratio of NK cells in UCB, GVL will not decrease after UCB transplantation. The lower contents of myeloid and lymphoid progenitor cells in UCB probably accounted for the slow hematopoiesis and immune reconstitution following UCB transplantation.

Adult↗

PubMed2002

Expression of caspase-3 in CD34+ cord blood cells and its significance.

To evaluate expression of caspase-3 protein in CD34(+) cells from cord blood (CB) and its significance during culture in vitro with various growth factors, RT-PCR, Western blot and flow cytometry were used to determine cell proliferation, apoptosis and expression of caspase-3 in CD34(+) cells during culture in vitro. The results demonstrated that caspase-3 mRNA was constitutively expressed at a low level in freshly isolated CD34(+) cells. Expression of caspase-3 mRNA and protein was upregulated when these cells were expanded in suspension culture with growth factors for 3 days. However, only the 32 kD inactive caspase-3 proenzyme was detected in the freshly isolated CD34(+) cells and those cells after 3 days expansion with cytokines. Along with the culture time extension (7 days) in vitro, especially without early-effective cytokines SCF or FL existence, caspase-3 was activated and a cleavage 20 kD was detected. It is concluded that the caspase-3 is involved in apoptosis of primitive CD34(+) cells during expansion in vitro, and early-effective cytokines, SCF and FL, could conserve hematopoietic stem cells and suppress apoptosis.

Antigens, CD34↗

PubMed2002

[Functional expression of Flt3 and c-kit on cord blood CD34(+) stem/progenitor cells and its significance].

To investigate the expression and function of the receptors of early-acting cytokines on cord blood CD34(+) hematopoietic stem/progenitor cells, the studies of Flt3 and c-kit were undertaken at the gene and protein levels. Fresh and cultured cord blood CD34(+) stem/progenitor cells were analyzed by flow cytometric two-color direct immunofluorescence methods and RT-PCR, while function of receptors was studied in vitro. It was found that (68.8 +/- 15.4)% of CD34(+) cells expressed Flt3, (50.6 +/- 12.7)% of CD34(+) cells expressed c-kit, the proportion of CD34(+) cells expressing Flt3 and c-kit decreased as in vitro culture time extended. It was concluded that cord blood CD34(+) stem/progenitor cells are capable of expressing Flt3 and c-kit for as long as 2 - 3 weeks in liquid medium, during the first week of culture, SCF and FL enhanced the generation of cells and progenitors notably.

Antigens, CD34↗

PubMed2002

[Apoptosis of Fas(+) Yac-1 cells induced with Fas ligand-transfected COS-7 cells].

The possibility of immunotherapy for lymphoma by single FasL-Fas way was investigated. After pBillneo-mFasL was transformed into competent E. coli DH5alpha and amplified, the plasmid DNA was prepared and purified from the DH5alpha. To determine the primary structure and inserting direction of mFasL cDNA gene in pBillneo-mFasL, the plasmid DNA was cleaved by restriction enzyme, and the mFasL cDNA of pBillneo-mFasL was amplified by polymerase chain reaction (PCR), the DNA sequence of the PCR product was analysed by automatic DNA sequencing. After pBillneo-mFasL was transfected into COS-7 cells by liposome, the COS-7 cells were selected with G418 selective medium, and the expressing levels of mFasL cDNA on the COS-7 cell membrane was assayed by Western Blot. After the COS-7 cells higher expressing mFasL protein and mouse lymphoma cell line Yac-1 expressing Fas were cocultured for 5 hours, the suspending Yac-1 cells were collected and labeled by annexin V/PI kit. The apoptosis rate of the Yac-1 cells was tested by flow cytometry. The EcoRI cleaving products of pBillneo-mF asL included 920 bp and 7227 bp fragments. Its Hind III cleaving products included 1293 bp and 6807 bp fragments. These results showed: (1) the length of DNA sequence containing mFasL cDNA within pBillneo-mFasL is the same as theoretical length; (2) the inserting of mFasL cDNA in pBillneo-mFasL was in positive orientation. The expected 890 bp DNA fragments of mFasL cDNA (from ATG to +36 bp following TAA) emerged in PCR product with pBillneo-mFasL as a template. The sequencing result of the PCR product equaled the known mFasL cDNA sequence in the gene bank. The COS-7 cells transfected by pBillneo-mFasL and selected with G418 culture medium expressed more mFasL membrane protein assayed by Western Blot. After the COS-7 cells were cocultured with Fas(+) Yac-1 cells in different E:T ratios (1:1, 5:1 and 10:1) for 5 hours, the apoptosis rates of Yac-1 cells were (22 +/- 4.8)%, (32.18 +/- 7.8)%, and (51.8 +/- 5.4)%, respectively. These were obviously different from the control group (P < 0.01), in which the COS-7 cell was transfected by pBillneo (not carrying mFasL gene). It was concluded that lymphoma cells highly expressing Fas can be effectively killed through single Fas-FasL way in vitro.

Animals↗

PubMed2002

[Study on expression and function of fas ligand in human myeloid leukemia cells].

To determine whether the Fas receptor-Fas ligand (FasR-FasL) system, which triggers apoptosis in sensitive cells, is an important mechanism of cytotoxicity in myeloid leukemia. FasL expression was investigated in myeloid leukemia cells and its upregulation by a combination of IL-2 and INF-gamma, +/- as well as its function of inducing Jurkat cells to apoptosis mainly by flow cytometry (FCM). Results showed that leukemia cells expressed more FasL (3.59 +/- 1.05)% than that expressed in the healthy individuals (0.36% +/- 0.16)%, P < 0.001 and the FasL was upregulated (7.78 +/- 3.40)%, P < 0.01 when treated with IL-2 and IFN-gamma. Leukemia cells were co-cultivated with Jurkat cells for 24 hours. Then Jurkat cells were labeled with FITC-annexin V and PE-CD3 to assess apoptosis by FCM. The leukemia cells, which had been incubated with IL-2 and IFN-gamma, induced more Jurkat cells to apoptosis than the ones that freshly isolated from the peripheral blood mononuclear cells, which raised the figure from (8.28 +/- 1.61)% to (10.73 +/- 2.16%). And the supernatant derived from the former killed more Jurkat cells than the latter. It was concluded that human myeloid leukemia cells expressed high levels of functional FasL that can kill Jurkat T-cells by apoptosis. FasR-FasL sys tem could play a role in the "immune escape" and relapse of the leukemia. The induction of apoptosis through the Fas pathway might be a novel and effective approach for leukemia immunotherapy.

Adolescent↗

PubMed2002

[Retroviral vector-mediated in vitro expression of human soluble fas].

Leukemic cells from patients expressed high level FasL cause apoptosis of autologous activated T cells via the Fas/FasL pathway. To investigate the role of soluble Fas (sFas) in reversing this process, a retroviral-mediated expression vector pLXIN-sFas was established. A retroviral-mediated expression system of human sFas was established in vitro and the biological activity of the expression product sFas was observed. To obtain the soluble Fas cDNA, the specific part of the full-length Fas cDNA was deleted by multiple PCR. After pLXIN-sFas packaged by PA317 cells, it was transferred into the target cell COS-7. The quantity of the sFas was (2.2 +/- 0.7) micro g/ml in supernatant of cultured COS-7 cells, and it could greatly inhibit apoptosis of Jurket cells induced by anti-Fas antibody. Our results suggested that the recombinant is able to express the target proteins in vitro and it has the perfect biological activity.

3T3 Cells↗

PubMed2002

[Apoptosis of the allo-antigen specific T cells induced by CD34(+) cells transfected with exogenous gene FasL].

To investigate the value of apoptosis of the allo-antigen specific T cells induced by Fas/FasL pathway in order to prevent GVHD in allo-transplant, the CD34(+) cells were transfected with FasL or not, used as effector cells, mixed with allo-antigen specific T lymphocytes with presence or absence of IFN-gamma or IL-2. After 5 days, apoptosis of T cells was detected by TdT nick end mediated dUTP labeling (TUNEL) and flow cytometry. The effects of IFN-gamma or IL-2 on apoptosis of CD34(+) cells of graft induced by Fas/FasL pathway observed as controls. The apoptosis incidence of T cells was (12.1 +/- 1.5)% when CD34(+) cells transfected with FasL were used as effector cells, that was much higher than that T cells with CD34(+) cells non-transfected (p < 0.01). In the presence of IFN-gamma or IL-2, apoptosis incidence reached to (20.1 +/- 2.3)% or (17.6 +/- 1.3)% respectively (p < 0.01). When sFasL was added to CD34(+) cells freshly isolated or induced with IFN-gamma or IL-2, the incidence or apoptosis of CD34(+) cells was (7.8 +/- 0.8)%, (18.7 +/- 1.6)% (p < 0.01) or (7.9 +/- 1.0)% (P > 0.05) respectively. The results suggest that it is possible to induce apoptosis of the allo-antigen specific T cells in grafts activated by allo-antigen by exogenous Fas ligand expressed on receptor cells and that may hopefully provide a new method to prevent GVHD

Animals↗

PubMed2002

[The expression and functional characteristics of AC133 antigen in cord blood hematopoietic cells].

OBJECTIVE: To explore the significance of AC(133) antigen expression on cord blood (CB) hematopoietic cells. METHODS: The immunophenotype of CB hematopoietic cells was analyzed by flow cytometric two-color direct immunofluorescence method. Hematopoietic activity of AC(133)(+), CD(34)(+) and AC(133)(-) CD(34)(+) cells in CB was examined by analyzing clonogenic capacity, number of LTC-IC and ex vivo expansion ability. RESULTS: AC(133)(+) cells consisted of 0.67% of the total CB MNCs. Of the AC(133)(+) cells, 93.4% expressed CD(34) antigen and 94.2% was PKH(26)(+). Although the total number of CFC was the same in the AC(133)(-) CD(34)(+) fraction as in the CD(34)(+) and AC(133)(-) fractions, the number of LTC-IC was much higher in the AC(133)(+) fraction. In addition, the features of the colonies grown from these three fractions were quite different. Approximately 50% of the colonies derived from the AC(133)(+) fraction were CFU-GM, whereas more than 60% of the colonies derived from the CD(34)(+) fraction and 80% of the colonies derived from the AC(133)(-) CD(34)(+) fraction were BFU-E. After 7 d ex vivo expansion, the total number of cells and CFC increased 28.2-fold and 7.1-fold respectively in AC(133)(+) cell populations, 6.8% of the cells was PKH(26)(+). CONCLUSIONS: These findings suggest that the early stem/progenitor cells of CB are enriched in AC(133)(+) fraction, AC(133)(+) cells contain higher proliferative efficiency during ex vivo culture. It can generate either committed progenitors or early stem/progenitors. AC(133) antigen would be a useful marker for clinical selection of hematopoietic stem/progenitors.

AC133 Antigen↗

PubMed2001

[Antisense Oligodeoxynucleotide Directed to NF-kappaB-RelA Down-Regulates bcl-x(L) mRNA in Drug-Resistant Leukemia Cell Line HL-60/E6]

In order to explore the effect of nuclear factor-kappa B (NF-kappaB) on bcl-x gene transcrtiption in drug-resistant leukemia cell line HL-60/E6, first of all, drug-resistant subline HL-60/E6 was derived by intermittently exposing HL-60 cells to 6 ng/ml epirubicin, and then bcl-x(L) mRNA levels were detected by RT-PCR after exposing HL-60/E6 cells to 5 micro mol/L AS-PS-ODN-RelA at different times. Morever, indirect immuno-fluorescence and FCM were used to demonstrate the location of NF-kappaB-RelA in HL-60/E6 cells and the efficiency of liposome-mediated ODN transfection. The results showed that RelA kept active and located at the nuclei of HL-60/E6 cells, and the efficiency of liposome-mediated ODN transfection was significantly higher than that of null ODN (P < 0.01 in 4, 6 and 12 h). Exposure of HL-60/E6 cells to 5 micro mol/L AS-PS-ODN-RelA led to a maximal 40% decline of bcl-x(L) mRNA levels. No significant change of bcl-x(L) mRNA level occurred in control group. It was concluded that NF-kappaB was involved in regulating bcl-x transcription. Suppressing NF-kappaB-RelA by antisense technology may down-regulate level of bcl-x(L) mRNA.

Journal Article↗