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ABSTRACT: To analyze the drift of T cell receptor (TCR) Vα and Vβ gene family CDR3 spectratype in response to ovarian carcinoma cells mediated by an anti-human ovarian carcinoma/CD3 bispecific single-chain antibody (BHL-1), and explore the mechanism of the bispecific single-chain antibody-mediated T cell immune response.
Immunoscopic spectratyping technique was used to analyze the TCR repertoire diversity (CDR3 spectratype distribution) of the T cells from 6 healthy donors before and after stimulation of the cells with human ovarian carcinoma in the presence of BHL-1. The predominant usage of TCR α and Vβ chain CDR3 was analyzed after the stimulation, and sequence analysis was performed for the CDR3 region of the monoclonal T cells.
The spectratypes of Vα and Vβ gene family TCR CDR3 region showed a Gaussian distribution before stimulation of the T cells from the 6 donors. After stimulation of the T cells, CDR3 spectratype drift occurred in the T cells, and some TCR Vα and Vβ families showed an anomalous and oligoclonal expansion. Different CDR3 sequences of the Vα and Vβ gene family TCR were found in the monoclonal T cells stimulated with BHL-1.
CDR3 spectratype drift occurs in TCR α and Vβ chains of T cells after stimulation with human ovarian carcinoma cells and BHL-1, indicating that the predominant usage of TCR Vα and Vβ families is associated with the specific T cell immune response mediated by BHL-1.
Nan fang yi ke da xue xue bao = Journal of Southern Medical University 07/2012; 32(7):919-23.
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ABSTRACT: Secondary rearrangements of the T cell receptor (TCR) represent a genetic correction mechanism which changes T cell specificity by re-activating V(D)J recombination in peripheral T cells. Murine T-cell hybridoma A1.1 was employed to investigate whether antigenic stimulation induced re-expression of recombinase genes and altered TCR Vβ expression. Following repeated antigenic stimulation, A1.1 cells were induced to re-express recombination activating gene (RAG)1 and terminal deoxynucleotidyl transferase (TdT) which are generally considered prerequisite to TCR gene rearrangement. Accompanied with the significant changes in TCR mRNA levels over time, it is suggested that secondary rearrangements may be induced in A1.1 cells, which represent a mature T cell clone capable of re-expressing RAG genes and possesses the prerequisite for secondary V(D)J rearrangement.
Cellular Immunology 03/2012; 274(1-2):19-25. · 1.97 Impact Factor
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ABSTRACT: Mesenchymal stem cells (MSCs) play a crucial role in tissue repair by secretion of tissue nutrient factors such as hepatocyte growth factor (HGF). However, studies examining the effects of HGF on the proliferation and differentiation of MSCs used different concentrations of HGF and reported conflicting conclusions. This study aimed to determine the mechanisms by which different concentrations of HGF regulate MSC proliferation and osteogenic differentiation, and validate the mechanism in an animal model of early stage avascular necrosis of femoral head (ANFH). Our results demonstrate that a low concentration of HGF (20 ng/ml) preferentially promotes MSC osteogenic differentiation through increased c-Met expression and phosphorylation, Akt pathway activation, and increased expression of p27, Runx2 and Osterix. In contrast, a high concentration of HGF (100 ng/ml) strongly induced proliferation by inducing strong activation of the ERK1/2 signalling pathway. As validated by animal experiments, high localized expression of HGF achieved by transplantation of HGF transgenic MSCs into ANFH rabbits increased the number of MSCs. Subsequently, 2 weeks after transplantation, HGF levels decreased and MSCs differentiated into osteoblasts and resulted in efficient tissue repair. Our results demonstrate that sequential concentration changes in HGF control the proliferation and osteogenic differentiation of MSCs in vivo. This phenomenon can be exploited therapeutically to induce bone regeneration and, in turn, improve the efficacy of pharmacological intervention for ANFH treatment.
Journal of Cellular and Molecular Medicine 08/2011; 16(6):1260-73. · 4.13 Impact Factor
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Shan Wang,
Zhen Guo,
Peng Xia,
Tingting Liu,
Jufang Wang,
Shan Li,
Lihua Sun,
Jianxin Lu,
Qian Wen, Mingqian Zhou,
Li Ma,
Xia Ding,
Xiaoning Wang,
Xuebiao Yao
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ABSTRACT: Cytotoxic lymphocytes are key players in the orchestration of immune response and elimination of defective cells. We have previously reported that natural killer (NK) cells enter target tumor cells, leading to either target cell death or self-destruction within tumor cells. However, it has remained elusive as to the fate of NK cells after internalization and whether the heterotypic cell-in-cell process is different from that of the homotypic cell-in-cell event recently named entosis. Here, we show that NK cells undergo a cell-in-cell process with the ultimate fate of apoptosis within tumor cells and reveal that the internalization process requires the actin cytoskeletal regulator, ezrin. To visualize how NK cells enter into tumor cells, we carried out real-time dual color imaging analyses of NK cell internalization into tumor cells. Surprisingly, most NK cells commit to programmed cell death after their entry into tumor cells, which is distinctively different from entosis observed in the homotypic cell-in-cell process. The apoptotic cell death of the internalized NK cells was evident by activation of caspase 3 and DNA fragmentation. Furthermore, NK cell death after internalization is attenuated by the caspase inhibitor, Z-VAD-FMK, confirming apoptosis as the mode of NK cell death within tumor cells. To determine protein factors essential for the entry of NK cells into tumor cells, we carried out siRNA-based knockdown analysis and discovered a critical role of ezrin in NK cell internalization. Importantly, PKA-mediated phosphorylation of ezrin promotes the NK cell internalization process. Our findings suggest a novel regulatory mechanism by which ezrin governs NK cell internalization into tumor cells.
Cell Research 09/2009; 19(12):1350-62. · 8.19 Impact Factor
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ABSTRACT: Many viral epitope specific T cell receptors (TCRs) in MHC-matched individuals have been demonstrated to involve conserved amino acid motifs in beta chain complementarity-determining region 3 (CDR3). However, it is not sure whether the conserved motifs can also be found in TCR beta chain. In previous studies, we developed a modified method to enlarge the percentage of cytomegalovirus (CMV) pp65 peptide-specific CD8(+) T cells in PBMC by continuous peptide stimulation in vitro, which provides sufficient number of specific T cells for detection. In this study, we further analyzed the restrictive usage of TCR V alpha and V beta gene families and investigated the CDR3 gene sequence of pp65 peptide-specific CD8(+) T cells. Analysis of CDR3 spectratypes suggested a restricted usage of TCR alpha chain AV8, AV12, AV21, AV31 families and TCR beta chain BV3, BV14, BV21, BV23, BV11 families in donor CD8(+) T cells stimulated by pp65 peptide. The sequences of these T cells involved similar sequence (TX) G (X) A in CDR3 region of TCR alpha chain and L (XT) G (X) A in TCR beta chain.
Cellular & molecular immunology 05/2009; 6(2):105-10. · 2.99 Impact Factor
