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Publications (2)3.49 Total impact

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    ABSTRACT: CD28 is expressed abnormally on human multiple myeloma (MM) cells but the significance had not been identified until now. In this paper, we are suggesting that abnormal expression of CD28 might be a marker of tumour progression. We therefore took the approach of generating a hybridoma cell line capable of secreting agonist monoclonal antibody directed against human CD28 (agonist anti-CD28 mAb) and then determined the expression of CD28 molecules on the MM cell lines U266 and XG1. The biological effects of agonist anti-CD28 mAb on cell growth and proliferation of U266 and XG1 cell lines were then analysed. Our results showed that the expression of CD28 on U266 and XG1 was significantly higher than that of PBTC or Jurkat cells. We found that by adding the agonist anti-CD28 mAb to cultures of U266 and XG1 cells their rate of growth and proliferation was obviously inhibited. Further morphological and molecular analyses found that U266 and XG1 incubated with agonist anti-CD28 mAb showed signs of nuclear condensation, chromatin marginal changes, cells membrane breaking, and cytoplasmic shrinkage. Vacuoles and apoptotic bodies were also observed using a transmission electron microscope and the development of typical DNA laddering patterns were found by the use of electrophoresis assays, suggesting that U266 and XG1 cells were undergoing apoptosis induced by agonist anti-CD28 mAb in vitro.
    Cellular Immunology 01/2005; 236(1-2):154-60. · 1.74 Impact Factor
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    ABSTRACT: B7 family molecules are mainly expressed on the outer membrane of antigen-presenting cells. Here, our results demonstrate that CD80, CD86, and PD-L1 molecules are also expressed on T-cells that have been activated by simultaneous exposure to anti-CD3 and anti-CD28 mAbs, but PD-L2 and GL50 molecules were not detectable during the first six days of culture that follow such stimulation. We have analysed the time course of B7 family molecule expression on activated T-cells. CD28 and its ligands, CD80/CD86, have a high degree of co-localization and exhibit compartmental distribution on the membrane of activated T-cells, which is visualized by confocal microscopy. Interestingly, the co-localization of PD-1 and its ligand also exhibit similar phenomenon. Additionally, we provide evidence indicating that the CD80, CD86, and PD-L1 molecules are functional, since T-cells expressing B7 family molecules are able to stimulate the proliferation of highly purified allogeneic or autologous T-cells. Anti-CD80, anti-CD86, and soluble CD28-Ig protein could significantly attenuate the proliferation of T-cells, whereas anti-PD-L1 mAb may lead to the expansion of activated T-cells. We can conclude that activated T-cells expressing B7 family molecules could act as "APC" to trigger purified T-cells, and B7 family molecules play important roles during the activation of T-cells. These results indicate a need for further work, exploring the regulatory roles these molecules may play in immune responses.
    Cellular Immunology 01/2005; 236(1-2):146-53. · 1.74 Impact Factor