Yi Tian

The Third Military Medical University, Chongqing, Chongqing Shi, China

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Publications (13)32.4 Total impact

  • Article: Cross-immunizing potential of tumor MAGE-A epitopes recognized by HLA-A*02:01-restricted cytotoxic T lymphocytes.
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    ABSTRACT: Almost all melanoma cells express at least one member of the MAGE-A antigen family, making the cytotoxic T cells (CTLs) epitopes with cross-immunizing potential in this family attractive candidates for the broad spectrum of anti-melanoma immunotherapy. In this study, four highly homologous peptides (P264: FLWGPRALA, P264I9: FLWGPRALI, P264V9: FLWGPRALV, and P264H8: FLWGPRAHA) from the MAGE-A antigens were selected by homologous alignment. All four peptides showed high binding affinity and stability to HLA-A*02:01 molecules, and could prime CTL immune responses in human PBMCs and in HLA-A*02:01/K(b) transgenic mice. CTLs elicited by the four epitope peptides could cross-lyse tumor cells expressing the mutual target antigens, except MAGE-A11 which was not tested. However, CTLs induced by P264V9 and P264I9 showed the strongest target cell lysis capabilities, suggesting both peptides may represent the common CTL epitopes shared by the eight MAGE-A antigens, which could induce more potent and broad-spectrum antitumor responses in immunotherapy.
    BMB reports 07/2012; 45(7):408-13. · 1.72 Impact Factor
  • Article: A novel splice variant of folate receptor 4 predominantly expressed in regulatory T cells.
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    ABSTRACT: Regulatory T cells (Tregs) are required for proper maintenance of immunological self-tolerance and immune homeostasis. Folate receptor 4 (FR4) is expressed at high levels in transforming growth factor-beta (TGF-β)-induced Tregs and natural Tregs. Moreover, antibody-mediated targeting of FR4 is sufficient to mediate Treg depletion. In this study, we describe a novel FR4 transcript variant, FR4D3, in which exon 3 is deleted. The mRNA of FR4D3 encodes a FR4 variant truncated by 189 bp. FR4D3 was found to be predominantly expressed in CD4(+)CD25(+) Treg cells. Overexpression of FR4D3 in CD4(+)CD25(+) Treg cells in vitro stimulated proliferation, which may modulate the ability of these cells to bind and incorporate folic acid. Our results suggested that high levels of FR4D3 may be critical to support the substantial proliferative capacity of Treg cells.
    BMC Immunology 06/2012; 13:30. · 2.53 Impact Factor
  • Article: Identification of interacting proteins of retinoid-related orphan nuclear receptor gamma in HepG2 cells.
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    ABSTRACT: The retinoid-related orphan nuclear receptor gamma (ROR γ) plays critical roles in regulation of development, immunity and metabolism. As transcription factor usually forms a protein complex to function, thus capturing and dissecting of the ROR γ protein complex will be helpful for exploring the mechanisms underlying those functions. After construction of the recombinant tandem affinity purification (TAP) plasmid, pMSCVpuro ROR γ-CTAP(SG), the nuclear localization of ROR γ-CTAP(SG) fusion protein was verified. Following isolation of ROR γ protein complex by TAP strategy, seven candidate interacting proteins were identified. Finally, the heat shock protein 90 (HSP90) and receptor-interacting protein 140 (RIP140) were confirmed to interplay with ROR γ by co-immunoprecipitation. Interference of HSP90 or/and RIP140 genes resulted in dramatically decreased expression of CYP2C8 gene, the ROR γ target gene. Data from this study demonstrate that HSP90 and RIP140 proteins interact with ROR γ protein in a complex format and function as co-activators in the ROR γ-mediated regulatory processes of HepG2 cells.
    BMB reports 06/2012; 45(6):331-6. · 1.72 Impact Factor
  • Article: Effect of thymosin alpha-1 on subpopulations of Th1, Th2, Th17, and regulatory T cells (Tregs) in vitro.
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    ABSTRACT: Thymosin alpha 1 (Tα1) has been shown to have beneficial effects on numerous immune system parameters, but little is known about the effects of Tα1 on patients with gastric carcinoma. The objective of this study was to determine the effect of Tα1 on subpopulations of Th1, Th2, Th17, and regulatory T cells (Tregs) in vitro, and to evaluate its efficacy as an immunoregulatory factor in patients with gastric carcinoma. We compared the effect of Tα1 on the frequency of CD4+ and CD8+ T cells, especially the CD4+CD25+Foxp3+ Tregs in peripheral blood mononuclear cells (PBMCs) from gastric carcinoma patients (N = 35) and healthy donors (N = 22). We also analyzed the changes in the proliferation of PBMCs in response to treatment with Tα1, and examined the production of Th1, Th2, and Th17 cytokines by PBMCs and tumor-infiltrating lymphocytes. The treatment of PBMCs from gastric cancer patients, with Tα1 (50 µg/mL) alone increased the percentage of CD4+CD25+Foxp3+ (suppressive antitumor-specific Tregs) from 1.68 ± 0.697 to 2.19 ± 0.795% (P < 0.05). Our results indicate that Tα1 increases the percentage of Tregs and IL-1β, TNF-α, and IL-6 in vitro.
    Brazilian journal of medical and biological research = Revista brasileira de pesquisas medicas e biologicas / Sociedade Brasileira de Biofisica ... [et al.] 01/2012; 45(1):25-32. · 1.08 Impact Factor
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    Article: Effects of telbivudine treatment on the circulating CD4⁺ T-cell subpopulations in chronic hepatitis B patients.
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    ABSTRACT: CD4⁺ T cells serve as master regulators of the adaptive immune response to HBV. However, CD4⁺ T-cell subsets are heterogeneous, and it remains unknown how the antiviral agents affect the different CD4⁺ T cell subtypes. To this end, the expressions of signature transcription factors and cytokines of CD4⁺ T-cell subtypes were examined in hepatitis B patients before and after treatment with telbivudine. Results showed that, upon the rapid HBV copy decrease induced by telbivudine treatment, the frequencies and related cytokines of Th17 and Treg cells were dramatically decreased, while those for Th2 cells were dramatically increased. No obvious changes were observed in Th1 cell frequencies; although, IFN-γ expression was upregulated in response to telbivudine treatment, suggesting another cell source of IFN-γ in CHB patients. Statistical analyses indicated that Th17 and Tr1 (a Treg subtype) cells were the most sensitive subpopulations of the peripheral blood CD4⁺ T cells to telbivudine treatment over 52 weeks. Thus, Th17 and Tr1 cells may represent a suitable and effective predictor of responsiveness during telbivudine therapy. These findings not only improve our understanding of hepatitis pathogenesis but also can aid in future development of appropriate therapeutic strategies to control viral hepatitis.
    Mediators of Inflammation 01/2012; 2012:789859. · 3.26 Impact Factor
  • Article: A novel self-assembled nanoparticle vaccine with HIV-1 Tat₄₉₋₅₇/HPV16 E7₄₉₋₅₇ fusion peptide and GM-CSF DNA elicits potent and prolonged CD8⁺ T cell-dependent anti-tumor immunity in mice.
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    ABSTRACT: Peptide-based vaccines derived from the E7 protein of human papillomavirus (HPV) type 16 were developed to induce effective T cell responses against established cervical cancer, but have met with limited clinical success. It is necessary to develop novel peptide-based strategies to substantially improve the immune response against HPV16-related cancer. In this study, we aimed to design a novel peptide-based self-assembled nanoparticle HPV16 vaccine by combining the cell-penetrating peptide HIV-1 Tat(49-57) that was fused with the HPV16 E7(49-57) cytotoxic T lymphocyte (CTL) epitope and the granulocyte-macrophage colony stimulating factor (GM-CSF) gene, and to investigate how it improves the immune response and the therapeutic outcome ex vivo and in vivo. Nanoparticles were prepared and identified by transmission electron microscopy (TEM), gel retardation and DNase I protection assays. This type of vaccine formulation formed the 20-80 nm nanoparticles, and greatly improved epitope-specific immunity both ex vivo and in vivo. Importantly, this vaccine type was associated with decreased tumor growth and enhanced long-term survival in the prophylactic and therapeutic mouse models. The underlying mechanisms were determined to involve priming of enhanced frequency of CD8(+) memory T subtype cells. These results suggest that the nanoparticle Tat-E7/pGM-CSF represents a promising novel approach to enhance the potency of peptide-based cervical cancer vaccines, and this vaccine design strategy may act as a useful reference for research of virus-associated diseases and specific tumor immunotherapies.
    Vaccine 12/2011; 30(6):1071-82. · 3.77 Impact Factor
  • Article: FSCB phosphorylation in mouse spermatozoa capacitation.
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    ABSTRACT: It is generally accepted that spermatozoa capacitation is associated with protein kinase A-mediated tyrosine phosphorylation. In our previous study, we identified the fibrous sheath CABYR binding protein (FSCB), which was phosphorylated by PKA. However, the phosphorylation status of FSCB protein during spermatozoa capacitation should be further investigated. To this aim, in this study, we found that phosphorylation of this 270-kDa protein occurred as early as 1 min after mouse spermatozoa capacitation, which increased over time and remained stable after 60 min. Immunoprecipitation assays demonstrated that the tyrosine and Ser/Thr phosphorylation of FSCB occurred during spermatozoa capacitation. The extent of phosphorylation and was closely associated with the PKA activity and spermatozoa motility characteristics. FSCB phosphorylation could be induced by PKA agonist DB-cAMP, but was blocked by PKA antagonist H-89.Therefore, FSCB contributes to spermatozoa capacitation in a tyrosine-phosphorylated format, which may help in further elucidating the molecular mechanism of spermatozoa capacitation.
    BMB reports 08/2011; 44(8):541-6. · 1.72 Impact Factor
  • Article: Identification of a new MAGE-A10 antigenic peptide presented by HLA-A*0201 on tumor cells.
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    ABSTRACT: MAGE-A antigens belong to cancer/testis (CT) antigens that are expressed in tumors but not in normal tissues with the exception of testis and placenta. Among MAGE-A antigens, MAGE-A10 is extensively expressed in various histological types of tumors, representing an attractive target for tumor immunotherapy. Cytotoxic T lymphocytes (CTLs) play a key role in anti-tumor immune responses, so the identification of CTL epitopes derived from MAGE-A10 would contribute a lot to the design of epitope-based vaccines for tumor patients. In this study, we predicted HLA-A*0201-restricted CTL epitope peptides of MAGE-A10, followed by peptide/HLA-A*0201 binding affinity and complex stability assays, and induced peptide-specific CTL immune responses. Of the selected three peptides (designated P1, P2 and P3), P1 (MAGE-A10310-318, SLLKFLAKV) could elicit peptide-specific CTLs both in vitro from HLA-A*0201-positive PBMCs and in HLA-A*0201/Kb transgenic mice. And, the induced CTLs could lyse MAGE-A10-expressing tumor cells in a HLA-A*0201-restricted fashion but not MAGE-A10-negative tumor cells. Our results demonstrate that the peptide MAGE-A10310-318 is a HLA-A*0201-restricted CTL epitope of MAGE-A10 and could serve as a target for therapeutic antitumoral vaccination.
    Cancer biology & therapy 02/2011; 11(4):395-400. · 2.64 Impact Factor
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    Article: Global mapping of H3K4me1 and H3K4me3 reveals the chromatin state-based cell type-specific gene regulation in human Treg cells.
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    ABSTRACT: Regulatory T cells (Treg) contribute to the crucial immunological processes of self-tolerance and immune homeostasis. Genomic mechanisms that regulate cell fate decisions leading to Treg or conventional T cells (Tconv) lineages and those underlying Treg function remain to be fully elucidated, especially at the histone modification level. We generated high-resolution genome-wide distribution maps of monomethylated histone H3 lysine 4 (H3K4me1) and trimethylated H3K4 (H3K4me3) in human CD4(+)CD25(+)FOXP3(+) Tregs and CD4(+)CD25(+)FOXP3(-) activated (a)Tconv cells by DNA sequencing-by-synthesis. 2115 H3K4me3 regions corresponded to proximal promoters; in Tregs, the genes associated with these regions included the master regulator FOXP3 and the chemokine (C-C motif) receptor 7 (CCR7). 41024 Treg-specific H3K4me1 regions were identified. The majority of the H3K4me1 regions differing between Treg and aTconv cells were located at promoter-distal sites, and in vitro reporter gene assays were used to evaluate and identify novel enhancer activity. We provide for the first time a comprehensive genome-wide dataset of lineage-specific H3K4me1 and H3K4me3 patterns in Treg and aTconv cells, which may control cell type-specific gene regulation. This basic principle is likely not restricted to the two closely-related T cell populations, but may apply generally to somatic cell lineages in adult organisms.
    PLoS ONE 01/2011; 6(11):e27770. · 4.09 Impact Factor
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    Article: Activated IL-23/IL-17 pathway closely correlates with increased Foxp3 expression in livers of chronic hepatitis B patients.
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    ABSTRACT: Foxp3 protein plays a critical role in mediating the inflammatory response and can inhibit the proinflammatory IL-23/IL-17 pathway. However, the molecular interplay of Foxp3 and the IL-23/IL-17 pathway in patients with chronic hepatitis B (CHB) remains unclear. To this end, we analyzed the expression patterns of Foxp3- and IL-23/IL-17 pathway-related proinflammatory cytokines in 39 patients with acute-on-chronic liver failure, 71 patients with CHB and 32 healthy controls. Foxp3 expression was found to be elevated in and mainly expressed by the CD4+ T cell sub-population of peripheral blood mononuclear cells and liver tissues of patients with hepatitis B. The intrahepatic expression of Foxp3 strongly correlated with the copies of HBV DNA and the concentration of surface antigen, HBsAg. IL-23/IL-17 pathway-related proinflammatory cytokines were also found to be significantly increased in patients' liver tissues, as compared to healthy controls. Moreover, Foxp3 expression was strikingly correlated with the production of these cytokines in liver tissues of CHB patients. The closely-correlated increase of Foxp3 and IL-23/IL-17 pathway activity in HBV-infected livers suggests that the proinflammatory IL-23/IL-17 pathway had not been effectively suppressed by the host immune machinery, such as Treg (Foxp3) cells. Constitutive activation of the IL-23/17 pathway, thus, may support the chronic hepatitis B state.
    BMC Immunology 01/2011; 12:25. · 2.53 Impact Factor
  • Article: Reduced FOXP3 expression causes IPEX syndrome onset: An implication from an IPEX patient and his disease-free twin brother.
    Clinical Immunology 10/2010; 137(1):178-80. · 4.05 Impact Factor
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    Article: Identification of two novel HLA-A*0201-restricted CTL epitopes derived from MAGE-A4.
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    ABSTRACT: MAGE-A antigens belong to cancer/testis (CT) antigens that are expressed in tumors but not in normal tissues except testis and placenta. MAGE-A antigens and their epitope peptides have been used in tumor immunotherapy trials. MAGE-A4 antigen is extensively expressed in various histological types of tumors, so it represents an attractive target for tumor immunotherapy. In this study, we predicted HLA-A*0201-restricted cytotoxic T lymphocyte (CTL) epitopes of MAGE-A4, followed by peptide/HLA-A*0201 affinity and complex stability assays. Of selected four peptides (designated P1, P2, P3, and P4), P1 (MAGE-A4(286-294), KVLEHVVRV) and P3 (MAGE-A4(272-280), FLWGPRALA) could elicit peptide-specific CTLs both in vitro from HLA-A*0201-positive PBMCs and in HLA-A*0201/K(b) transgenic mice. And the induced CTLs could lyse target cells in an HLA-A*0201-restricted fashion, demonstrating that the two peptides are HLA-A*0201-restricted CTL epitopes and could serve as targets for therapeutic antitumoral vaccination.
    Clinical and Developmental Immunology 01/2010; 2010:567594. · 1.84 Impact Factor
  • Article: A novel splice variant of FR4 predominantly expressed in CD4+CD25+ regulatory T cells.
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    ABSTRACT: Folate receptor 4 (FR4) is recently found as a lymphoid tissue specific protein. In this study, we have identified an alternative splicing variant of the FR4 gene from murine splenocytes, termed FR4v, which is almost identical to FR4 cDNA sequence except with the retained 108 bp intron 3 between exon 3 and 4 of FR4 gene. FR4v mRNA encodes a larger protein than FR4 and is constitutively expressed on CD4(+)CD25(+) regulatory T cell (Treg) membrane via a GPI anchor mechanism. Whether FR4v plays a redundant or unique functional role in Tregs should be investigated further in the future.
    Immunological Investigations 01/2009; 38(8):718-29. · 1.47 Impact Factor