Xueling Chen

Huazhong University of Science and Technology, Wu-han-shih, Hubei, China

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Publications (5)15.27 Total impact

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    ABSTRACT: A fusion protein of single chain antibody (scFv) specific for transferrin receptor (TfR, CD71) and viral peptide/HLA-A2 complex was prepared in this study to redirect cytotoxic T cells (CTLs) of viral specificity to tumor cells by attaching the ligand of T cell receptor (TCR) to tumor cells via binding of TfR scFv to TfR. The results demonstrate that the fusion protein can attach the active virus-peptide/HLA-A2 complex to HLA class I-negative, TfR-expressing K562 cells through binding of TfR scFv to TfR, and mediate cytotoxicity of viral peptide-specific CTLs against K562 cells in vitro. In addition, the fusion protein can induce inhibition of solid tumor formation and improve survival time in tumor xenograft nude mouse with the injection of the sorted viral peptide-specific CTLs generated by co-culture of peripheral blood lymphocytes from HLA-A2 positive donors with inactivated T2 cells pulsed with the viral peptide.
    Cellular Immunology 01/2010; 263(2):154-60. · 1.74 Impact Factor
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    ABSTRACT: Human leukocyte antigen (HLA)-G, a nonclassical HLA class I molecule, induces a wide range of tolerogenic immunological effects by means of interaction with its inhibitory receptors. However, recent studies show that HLA-G dimer formation is essential to bind to its receptors and exhibit its effects. In this study, a soluble divalent HLA-G/IgG molecule (sHLA-G dimer) was constructed. Its inhibitory effect on T-cell alloresponse was studied with mixed lymphocyte reaction in vitro, which was set up by mixing inactivated T1 cells with HLA-mismatched peripheral blood lymphocytes in the presence or absence of the sHLA-G dimer. The results show that sHLA-G dimer inhibits T-cell alloresponse by reducing proliferation of both CD4+ and CD8+ T cells and suppressing generation of alloreactive cytotoxic T lymphocytes at nanomole concentration. The inhibition of the sHLA-G dimer is observed to be more effective than that of sHLA-G monomer. Our results also indicate that sHLA-G dimer up-regulates inhibitory receptor ILT2 on alloreactive CD8+ T cells, which contributes to the significant inhibition on T-cell alloresponse. The sHLA-G dimer formed by IgG-Fc fragment shows more inhibitory effects on alloreactive T cells, which may have implications for allotransplantation.
    Transplantation 02/2009; 87(1):8-15. · 3.78 Impact Factor
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    ABSTRACT: Generation and adoptive transfusion of alloreactive cytotoxic T lymphocytes (CTLs) specific for tumor are expected to circumvent tumor tolerance. Here we describe a novel protocol to raise allo-restricted, peptide-specific CTLs by co-culture of murine splenocytes and autologous macrophage bearing an allogeneic H-2K molecule associated with its restricted peptide (peptide/allo-MHC). The extracellular domains of H-2K(d) were fused with constant domains of murine IgG2a heavy chain to generate a fusion protein (peptide/H-2K(d)/IgG2aFc, the dimer) consisting of divalent TCR-ligands and an IgG Fc receptor type I (FcgammaRI)-reactive moiety. The dimer is able to bind to macrophage (Mvarphi) of H-2K(k) via the interaction of the Fc part with FcgammaRI, and cause the H-2K(k) Mvarphi to be coated with the peptide/H-2K(d) complex. The results show that proliferation of CD8+ cells is enhanced and that the specific-tetramer stained CD8+ cells appear more frequently by co-culture of H-2K(k) splenocytes with the autologous Mvarphi loaded with the dimer. Furthermore, the CD8+ T cells from the co-cultural bulk exhibit an elevated cytotoxicity against a specific target (H-2K(d)-restricted, peptide-specific cytotoxicity), compared with that against the irrelevant targets. This study provides a strategy for preparation of allo-restricted, peptide-specific CTLs, which may add to our arsenal for adoptive immunotherapy to eliminate chronic virally infected or tumor cells.
    Human immunology 01/2009; 70(2):79-84. · 2.55 Impact Factor
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    ABSTRACT: Induction of peripheral tolerance in an antigen-specific manner is a critical goal of transplant biology. The specificity and avidity of multimerized peptide/major histocompatibilty complexes suggest their potential ability to modulate antigen-specific T-cell sensitization and effector functions. A soluble divalent HLA-A2/IgG molecule (HLA-A2 dimer) was constructed and loaded with a self-protein origin peptide (Tyr(368-376)) to form a divalent Tyr/HLA-A2 molecule (Tyr/HLA-A2 dimer), which allowed for specific targeting to the epitope-specific cytotoxic T lymphocytes in bulk alloreactive T cells. Alloreactive T-cell response was induced by coculture of Tyr(368-376) -pulsed T2 cells (T2/Tyr) with peripheral blood lymphocytes of HLA-A2-negative (HLA-A2-ve) sample; five samples of HLA-A2-ve individuals were included in this study. After the coculture in the presence of Tyr/HLA-A2 dimer, the suppression of the dimer on alloresponse was characterized by analyzing allogeneic T-cell proliferation, specific cytolytic activity against the T2/Tyr, and specific Tyr/HLA-A2 tetramer staining. The Tyr/HLA-A2 dimer suppresses alloreactive T-cell response by inhibiting its proliferation and cytotoxicity against specific target T2/Tyr in vitro, and it is interesting that the suppression is peptide-specific. The Tyr/HLA-A2 tetramer staining suggests the reduced function of CD8+ T cell is caused by inhibiting the generation of the epitope-specific alloreactive T cells by the Tyr/HLA-A2 dimer in three samples. Moreover, the existence of epitope-specific but function-negative T cells in the other two samples suggests that another mechanism might exist that is involved in silencing alloreactive responses by the dimer. Peptide-loaded dimers offer a novel approach to induce peptide-specific immunosuppression and may be useful in promoting graft survival.
    Transplantation 12/2007; 84(10):1298-306. · 3.78 Impact Factor
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    ABSTRACT: Peptide-MHC class I complex (pMHC) is a specific ligand for TCR recognition, and important for CD8+ T cell activation. Here we described a genetically engineered divalent class I major histocompatibility complex (MHC) molecule, H-2Kd/IgG2aFc, a fusion protein consisting of the extracellular domains of H-2Kd, a murine MHC class I molecule, and the Fc region of IgG2a. This fusion protein is expected to attach the H-2Kd molecule to the surface of murine macrophage (Mphi) through its Fc portion binding to Fc receptor (FcR) of Mphi. cDNAs coding for the extracellular domains of H-2Kd and the Fc region of IgG2a were cloned respectively, and then recombined into plasmid pcDNA3.1(+). The H-2Kd/IgG2aFc protein was expressed by the plasmid-transfected cell line J558L, and purified from its supernatant with a Staphylococcal Protein A (SPA) column. The fusion protein showed a 58.4 kDa band as revealed by SDS-PAGE and Western blotting with murine IgG-specific antibody, which consists with that expected for extracellular domains of H-2Kd heavy chain plus the Fc region of IgG2a. The sandwich ELISA assay with antibodies specific for Fc portion and for H-2Kd indicated the fusion protein consists of both Fc portion and H-2Kd. Peritoneal Mphi of C57BL/6 (H-2Kb) can be stained with H-2Kd specific monoclonal antibody (mAb) after incubated with the H-2Kd/IgG2aFc fusion protein. These results demonstrate the fusion protein can be used to attach the H-2Kd molecule to the surface of murine Mphi, and provides a novel means to manipulate the T cell recognized epitope on the surface of murine Mphi, which can be applied to activate antigen-specific cytotoxic T lymphocyte (CTL).
    Cellular & molecular immunology 05/2007; 4(2):147-51. · 3.42 Impact Factor