摘要
目的：
通过对Vav1与肿瘤浸润T淋巴细胞(tumor infiltrating T lymphocytes，TIL-T)活性的研究，提出肿瘤诱导的T细胞失能的分子机制；初步探讨TIL-T中Vav1基因的表达情况及其与肿瘤局部微环境中吲哚胺2，3双加氧酶(indoleamine-2，3-dioxygenase，IDO)的表达的相关性，提出肿瘤诱导的T细胞失能的一个可能的分子机制；分析IDO对T细胞活性、Vav1基因和蛋白表达水平，Vav1蛋白磷酸化及其下游信号分子[Ca2+]流、MAPK、NF-κB等的影响，同时测定IL-2基因的表达水平。提出TIL-T中Vav1信号异常的可能机制；提出调控TIL-T活性的方法，为纠正肿瘤诱导的免疫抑制提供新的解决方法。
内容：
1)检测TIL-T中Vav1 mRNA的表达水平，分析其与T细胞活性、肿瘤局部IDO表达水平的相关性。
2)体外以稳定表达IDO的CHO细胞与T细胞共孵育，观察IDO对T细胞增殖、凋亡的影响，以及对Vav1基因、蛋白表达及Vav1蛋白活化的作用；观察IDO对T细胞中Vav1下游信号主要传导途径[Ca2+]流、MAPK及NF-κB的变化。探讨IDO在调控Vav1表达和活化中的作用，以及Vav1进一步调节T细胞活性的机制。
3)将IDO抑制剂1-甲基色氨酸(1-MT)加入共孵育体系，观察T细胞增殖、凋亡以及Vav1信号途径的变化。
方法：
1)无菌条件下分离肺癌原位TIL-T及恶性胸腹水中的T淋巴细胞，在体外加入刺激活化因子，观察T淋巴细胞对刺激的反应性，同时检测T细胞中Vav1基因的表达水平；再用免疫组化的方法观察肺癌原位肿瘤组织中IDO蛋白的表达情况。
2)体外以稳定表达IDO的CHO细胞株与外周血正常T细胞共同培养，MTT法检测T淋巴细胞的增殖率，流式细胞仪检测T细胞凋亡，Real-time PCR法检测Vav1和IL-2 mRNA水平，Western blot免疫印迹和免疫沉淀的方法检测Vav1蛋白表达及磷酸化水平，及其下游分子ERK1／2、p38和IκBα的活化；应用细胞钙离子成像系统检测单细胞内[Ca~(2+)]i的动态变化。
3)以IDO抑制剂1-MT加入共孵育体系，观察T细胞增殖、凋亡以及Vav1基因蛋白表达水平和下游信号途径的变化。
结果：
1)在11例肺癌患者肿瘤原位手术标本中，3例TIL-T对活化刺激信号的反应性低下，只表现为极微的增殖反应；其余8例TIL-T对刺激信号的反应正常，可正常增殖。同样用刺激活化信号在体外对10例癌症患者癌性胸腹水中T淋巴细胞进行激活，我们观察到，所有病例所采集的T细胞均能正常增殖。
2)利用Real-time PCR的方法对肺癌原位TIL-T和癌性胸腹水中分离得到的T淋巴细胞中Vav1的mRNA含量进行了检测，结果显示可分为两组：对刺激信号反应正常的8例肺癌原位TIL-T和癌性胸腹水中的T细胞中，Vav1 mRNA含量与正常对照差异无统计学意义(P＞0.05)。而3例表现为“失能”状态的T细胞中Vav1的mRNA水平却非常低(P＜0.05)。
3)免疫组化检测显示所观察的肺癌患者标本中IDO阳性表达率为27.3％，肺癌原位组织及转移性淋巴结中IDO表达呈一致性。3例IDO表达阳性的肺癌组织，其中浸润T淋巴细胞中Vav1基因表达水平较对照组下降；8例IDO表达阴性的肺癌组织Vav1基因表达水平与对照组的差异无统计学意义(P＞0.05)。IDO表达阳性的3例标本中TIL-T对活化刺激信号的反应性低下。
4)稳定表达IDO的CHO细胞株经检测稳定表达IDO mRNA和蛋白，表达的IDO经氨基酸检测分析可分泌至细胞外并且发挥活性；将此细胞与T细胞共孵育后，T细胞增殖下降，凋亡增加；Vav1 mRNA及蛋白水平下降，磷酸化水平降低，而且Vav1下游分子的活化水平均降低；同时IL-2基因的表达下降。
5) 1-MT加入共孵育体系后，T细胞增殖及凋亡均可部分恢复，Vav1 mRNA及蛋白水平也可部分恢复。
结论：
1) Vav1基因的表达与肿瘤局部浸润的T淋巴细胞的活性具有相关性，与肿瘤局部微环境中IDO的表达水平具有相关性。部分肺癌原位肿瘤局部浸润的T淋巴细胞呈现为功能抑制状态，在这些“失能”细胞中信号传导蛋白Vav1的表达下降。免疫组化结果提示IDO可能是肿瘤局部微环境中影响T细胞中Vav1蛋白表达和活化的重要因素之一。
2) IDO抑制T细胞增殖，诱导T细胞凋亡。IDO对TCR信号传导通路具有调节作用。IDO及其代谢产物可能通过抑制T细胞中信号传导蛋白Vav1及其下游分子的表达和活化而抑制T细胞功能。
3) Vav1的低表达和活化障碍，导致其下游分子的活化障碍，以致IL-2因子的合成和分泌减少，使T细胞增殖抑制。Vav1的下调与T细胞的凋亡是否有关仍需进一步探索。
4) Vav1信号通路在IDO诱导的T细胞凋亡中的作用尚需进一步探索。本研究为进一步探讨IDO在病理或生理情况下对T细胞的抑制作用提供了另一个研究方向，初步探索了调控肿瘤局部T淋巴细胞功能的方法，同时为抗肿瘤免疫治疗方法的发展提供了新的治疗方法。
Purpose:
This study intendes to investigate the relationship between the signal transducerVavl and the activity of tumor infiltrating T lymphocytes (TIL-T).Indoleamine-2,3-dioxygenase (IDO), a tryptophan catabolic enzyme, plays animportant role in immune escape through suppressing T-cell function. Since Vavlsignaling pathway regulates T cell homeostasis, this study was designed to test thehypothesis that IDO induces T-cell immunosuppression through inhibiting Vavlsignaling.
Materials and Methods:
Firstly, we investigate the expression of Vavl gene in TIL-T. Then theexpression of IDO in the tumors is detected by immunohistochemistry (IHC).
Chinese hamster ovary (CHO) cells were stably transfected with human IDO(CHO/IDO). The transcription and expression of IDO gene were detected by RT-PCRand Western blot analysis, respectively. The enzyme activity of IDO was measuredusing Hitachi amino acid automatic analyzer. CD3~+ T cells were isolated from humanperipheral blood monouclear cells and sorted by CD3~+ microbeads in MACS. Afterco-culture of CHO/IDO cells with T cells in the presence or absence of an anti-CD3antibody which can activate T cell receptor (TCR) and/or 1-methyl-L-tryptophan(1-MT) which can inhibit IDO activity, T cell proliferation and apoptosis weredetermined. T cell total RNA and cellular protein samples were isolated for detectingVavl gene and protein expression and activate state as well as the activation of thedownstream signal transducers of Vavl by realtime-PCR and immunoprecipitation orimmunoblotting.
Results:
T cells isolated from some patients have low response to the stimuli, and can notproliferate normally. Moreover, the level of Vavl expression in these TIL-T is lowerthan the T cells isolated from PBMC.
The positive rate of IDO expression is 27.3% in our experiment. The IDOexpression in tumor tissues is consistent with that in metastatic lymph nodes. In the IDO positive tissues, the levels of Vavl in TIL-T are lower than normal(P＜0.05).
The expression of IDO in transfected CHO cells was identified by RT-PCR andWestern blotting. And the IDO transgenic CHO cells yielded a high enzyme activityand resulted in complete depletion of tryptophan from the culture medium. We foundthat IDO produced by these IDO-expressing CHO cells significantly inhibitedinterleukin (IL)-2 expression and proliferative response in T cells and increased theapoptosis of T cells. IDO suppressed Vavl mRNA and protein production in T cells.Furthermore, IDO inhibited TCR activation-induced Vavl phosphorylation, whichrepresents Vavl's activation state and the activation of the downstream signaltransducers of Vavl in T cells. These effects on T-cells induced by co-culture ofCHO/IDO can be were attenuated by 1-MT.
Conclusions:
The activities of TIL-T correlate with the expression of Vavl. Vavl expressionis defective in T cells in the microinviroment of some tumors.
The low expression and activity of Vavl lead to the deficiency of IL-2 synthesis,and then T cells cannot proliferation normally in respond to stimuli.
The inhibitory effects of IDO on T cell immune responses may be throughdown-regulating of Vavl protein expression and activation. These studies provideinsights into the mechanisms of immune escape induced by IDO and the therapeuticapplication of IDO inhibitors for cancer treatments.
引文
[1]Rosenberg SA. Progress in human ttlmonr immunology and immunotherapy[J]. Nature, 2001, 411 (6835): 380-384.
[2]Elke J, Dirk J, Alexander K. Clinical cancer vaccine trials[J]. Current Opinion in Immunology, 2002, 14 (2): 178-182.
[3]Olivera IF. Cancer vaccines: between the idea and the reality[J]. Nature Reviews Immunology, 2003.3: 630-641.
[4]Jay A, Berzofsky, Jeffrey D, et al. Strategies for designing and optimizing new generation vaccines[J]. Nature Reviews Immunology, 2001, 1: 209-219.
[5]Prendergast GC, Jaffee EM. Cancer immunologists and cancer biologists: why didn't talk then but need to now[J]. Cancer Res, 2007, 67: 3500-3504.
[6]Berzofsky JA, Jeffrey D, et al. Strategies for designing and optimizing new generation vaccines[J]. Nature Reviews Immunology, 2001; 1: 209-219.
[7]Nomum T, Sakaguchi S. Naturally arising CD25~+CD4~+ regulatory T cells in tumor immunity. Curr Top Microbiol Immunol, 2005, 293: 287-302.
[8]Yang zz, Novak AJ, Stenson MJ, et al. Intratumoral CD4~+CD25~+ regulatory T-cell-mediated suppression of infiltrating CD4~+ T-cell in B-cell non-Hodgkin lymphoma[J]. Blood, 2006, 107: 3639-3646.
[9]Nicholl M, Lodge A, Brown I, et al. Restored immune response to an MHC-Ⅱ-Restricted antigen in tumor-bearing hosts after elimination of regulatory T cells[J]. J Pediatr Surg, 2004, 39: 941-946.
[10]Shevach EM. CD4~+CD25~+ suppressor T cells: more questions than answers[J]. Nat Rev Immunol. 2002, 2 (6): 389-400.
[11]Zea AH, Rodriguez PC, Atkins MB, et al. Arginase-producing myeloid suppressor cells in renal cell carcinoma patients: a mechanism of tumor evasion[J]. Cancer Res, 2005, 65: 3044-3048.
[12]Janeway CA, Travers P, Walport M, Capra JD. Immunobiology[M]. Fourth Edition, Elsevier Science, London, Taylor & Francis Group, New York, 1999. 550-560.
[13] Ochoa AC. Mechanisms of tumor escape from the immune response[M]. Taylor and Francis, London, 2003: 282.
[14] Chen Q, Daniel V, Maher DW, et al. Production of IL-10 by melanoma cells: examination of its role in immunosuppression mediated by melanoma[J]. Int J Cancer, 1994, 56 (5): 755.
[15] Kudoh S, Wang Q, Hidalgo OF, et al. Responses to T cell receptor/CD3 and interleukin-2 receptor stimulation are altered in T cells from B cell non-Hodgkin's lymphomas[J]. Cancer Immunol Immunother, 1995,41: 175-184.
[16] Wang Q, Stanley Jill, Kudoh S, et al. T cells infiltrating non-Hodgkin's B cell lymphomas show altered tyrosine phosphorylation pattern even though T receptor/CD3-associated kinases are present[J]. J Immunol, 1995: 1382-1392.
[17] Morford LA, Elliott LH, Carlson SL, Brooks WH, and Roszman TL. T cell receptor-mediated signaling is defective in T cells obtained from patients with primary intracranial tumors[J]. J Immunol, 1997: 4415-4425.
[18] Thornton MV, Kudo D, Rayman P, et al. Degradation of NF-kappa B in T cells by gangliosides expressed on renal cell carcinomas [J]. J Immunol, 2004,172 (6): 3480- 3490.
[19] Romero F, Fischer S. Structure and function of Vav [J]. Cell Signal, 1996, 8(8):545-553.
[20] Katzav S, Martin-Zanca D, Barbacid M. Vav, a novel human oncogene derived from a locus ubiquitously expressed in hematopoietic cells[J]. Embo J, 1989, 8 (8): 2283-2290.
[21] Lápez-Lago M, Lee H, Cruz C, et al. Tyrosine phosphorylation mediates both activation and downmodulation of the biological activity of Vav[J]. Mol Cell Biol, 2000,20:1678-1691.
[22] Tybulewicz VL, Ardouin L, Prisco A, et al. Vavl: a key signal transducer downstream of the TCR[J]. Immunol Rev, 2003, 192: 42-52.
[23] Gomez TS, Hamann MJ, McCarney S, et al. Dynamin 2 regulates T cell activation by controlling actin polymerization at the immunological synapse[J]. Nat Immunol, 2005, 6 (3): 261-270.
[24] Houlard M, Romero-Portillo F, Germani A, et al. Characterization of VIK-1: a new Vav-interacting Kruppel-like protein[J]. Oncogene, 2005,24 (1): 28-38.
[25] Katzav S. Flesh and blood: the story of Vavl, a gene that signals in hematopoietic cells but can be transforming in human malignancies[J]. Cancer Lett, 2007, 255 (2): 241-254.
[26] Turner M, Mee PJ, Walters AE, et al. A requirement for the Rho-family GTP exchange factor Vav in positive and negative selection of thymocytes[J]. Immunity, 1997, 7(4): 451-460.
[27] Kong YY, Fischer KD, Bachmann MF, et al. Vav regulates peptide-specific apoptosis in thymocytes[J]. J Exp Med, 1998, 188 (11): 2099-2111.
[28] Costello PS, Walters AE, Mee PJ, Turner M, Reynolds LF, Prisco A, et al. The Rho-family GTP exchange factor Vav is a critical transducer of T cell receptor signals to the calcium, ERK, and NF-kappaB pathways[J]. Proc Natl Acad Sci USA 1999;96(6):3035-3040.
[29] Fischer KD, Kong YY, Nishina H, et al. Vav is a regulator of cytoskeletal reorganization mediated by the T-cell receptor[J]. Curr Biol, 1998, 8(10): 554-562.
[30] Holsinger LJ, Graef IA, Swat W, et al. Defects in actin-cap formation in Vav-deficient mice implicate an actin requirement for lymphocyte signal transduction[J]. Curr Biol, 1998, 8 (10): 563-572.
[31] Koneru M, Schaer D, Monu N, et al. Defective proximal TCR signaling inhibits CD8~+ tumor-infiltrating lymphocyte lytic function[J]. J Immunol, 2005,174 (4): 1830-1840.
[32] Thomas F, Gajewski, Meng Yuru, et al. Immune Suppression in the tumor microenvironment[J]. J Immunother, 2006,29 (3): 233-240.
[33] Prado-Garcia H, Avila-Moreno F, and Lopez-Gonzalez JS. Cytotoxic T lymphocytes in cancer and autoimmunity[J]. Rev Invest Clin, 2004, 56 (5): 629-639.
[34] Andrew M. Indoleamine 2,3 dioxygenase and regulation of T cell immunity[J]. Biochem Biophys Res Comman, 2005, 338 (1): 20-24.
[35] Munn DH, Sharma MD, Lee JR, et al. Potential regulatory function of human dendritic cells expressing indoleamine 2,3-dioxygenase[J]. Science, 2002,297 (5588): 1867-1870.
[36] Yoshida R, Nukiwa T, Watanabe Y, et al. Regulation of indoleamine 2,3-dioxygenase activity in the small intestine and the epididymis of mice[J]. Arch Biochem Biophys, 1980, 203 (1): 343-351.
[37] Mellor AL, Munn DH. Tryptophan catabolism and T cell tolerance: immunosuppression by starvation[J]. Immunol Today, 1999, 20 (10): 469-473.
[38] Muun DH, Zhou M, Attwood JT, et al. Prevention of allogeneic fetal rejection by tryptophan catabolism[J]. Science 1998, 281 (5380): 1191-1193.
[39] Mellor AL, Munn DH. IDO expression by dendritic cells: tolerance and tryptophan catabolism[J]. Nat Rev Immunol, 2004,4 (10): 162-11 A.
[40] Taylor MW, Feng GS. Relationship between interferon-gamma, indoleamine 2,3-dioxygenase and tryptophan catabolism[J]. FASEB J, 1991, 501: 2516-2522.
[41] Mellor AL, Munn DH. Tryptophan Catabolism and Regulation of Adaptive Immunity[J]. J Immunol, 2003, 170: 5809-5813.
[42] Fallarino F, Grohmann U, Vacca C, Bianchi R, Orabona C, Spreca A, Fioretti MC, and Puccetti P. T cell apoptosis by tryptophan catabolism[J]. Cell Death Differ, 2002,9: 1069-1077.
[43] Lee GK, Park HJ, Macleod M, Chandler P, Munn DH, and Mellor AL. Tryptophan deprivation sensitizes activated T cells to apoptosis prior to cell division[J]. Immunology, 2002, 107: 452-460.
[44] Terness P, Bauer TM, R(o|¨)se Lars, et al. Inhibition of Allogeneic T Cell Proliferation by Indoleamine 2,3-Dioxygenase-expressing dendritic cells: Mediation of Suppression by Tryptophan Metabolites[J]. J Exp Med, 2002, 196: 447-457
[45] Frumento G, Rita Rotondo, Michela Tonetti, Gianluca Damonte, Umberto Benatti, and Giovanni Battista Ferrara. Tryptophan-derived Catabolites Are Responsible for Inhibition of T and Natural Killer Cell Proliferation Induced by Indoleamine 2,3-Dioxygenase[J]. J Exp Med, 2002, 196: 459-468.
[46] Mellor AL, Baban B, Chandler P, et al. Cutting edge: induced indoleamine 2,3 dioxygenase expression in dendritic cell subsets suppresses T cell clonal expansion[J]. J Immunol, 2003, 171(4): 1652-1655.
[47] Curti A, Pandolfi S, Valzasina B, et al. Modulation of tryptophan catabolism by human leukemic cells results in the conversion of CD25~- into CD25~+ T regulatory cells[J]. Blood, 2007,109: 2871-2877.
[48] Uyttenhove C, Pilotte L, Theme I, et al. Evidence for a tumoral immune resistance mechanism based on tryptophan degradmion by indoleamine 2,3-dioxygenase[J]. Nat Med, 2003, 9 (10): 1269-1274.
[49] Teieher BA: Molecular cancer therapeutics: will the promise be fulfilled? In: Molecular cancer therapeutics: strategies for drug discovery and development. GC Prendergast (Ed.): John Wiley&Sons, Inc., Hoboken NJ, 2004: 7-40.
[50] MellorAL, Munn DH. Tryptophan catabolism and T_2 cell tolerance: immunosuppression by starvation[J]. Immunol Today, 1999, 20 (10): 469-473.
[51] Muller V, Witzel I, Luck HJ, Kohler G, et al. Prognostic and predictive impact of the HER-2/neu extracellular domain (ECD) in the serum of patients treated with chemotherapy for metastatic breast cancer[JJ. Breast Cancer Res Treat, 2004, 86 (1):9-18.
[52] Whiteside TL. Immune responses to malignancies[J]. J Allergy Clin Immunol, 2003, 111 (2 Suppl): S677-S686.
[53] Whiteside TL. Tumor-innltrating lymphocytes as antitumor effector cells[J]. Biotherapy, 1992, 5: 47-61.
[54] Sogn JA. Tumor immunology: the glass is half full[J]. Immunity, 1998, 9: 757-763.
[55] Lopez CB, Rao TD,Feiner H, Shapiro R, Marks JR and Frey AB. Repression of interleukin-2 mRNA translation in primary human breast carcinoma tumor-infiltrating lymphocytes[J]. Cell Immunol, 1998, 190: 141-155.
[56] Rabinowich H, Suminami Y, Reichert TE, Crowley-Nowich P, Bell M and Whiteside TL. Expression of cytokine genes or proteins and signaling molecules in lymphocytes associated with human ovarian Carcinoma[J]. Int J Cancer, 1996, 68: 276-284.
[57] Morford LA, Elliott LH, Carlson SL, Brooks WH, and Roszman TL. T Cell receptor-mediated signaling is defective in T Cells obtained from patients with primary intracranial tumors[J]. J Immunol, 1997:4415-4425.
[58]邹征云，刘宝瑞，杜娟等。一种分离自体肿瘤细胞与TIL细胞新方法的建立[J]。肿瘤防治杂志，2004，11(2)：153-156。
[59]Inoue Y, Shijubo N, Uede T, et al. Induction of killer cells from lymphocytes in pleural effusion of advanced lung cancer patients[J]. Jpn J Cancer Res, 1990, 81: 1012-1020.
[60]Koneru M, Schaer D, Monu N, Ayala A, and Frey AB. Defective proximal TCR signaling inhibits CD8~+ tumor-infiltrating lymphocyte lytic function[J]. J Immunol, 2005, 1830-1840.
[61]Hiroaki Y, Katsuji T, Rytaro Y, et al. Interferon enhances tryptophan metabolism by inducing pulmonary indoleamine 2,3-dioxygenase:Its possible occurrence in cancer patients[J]. Proc Nad Acad Sci. USA, 1986, 83 (4): 6622-6626.
[62]Brandacher G, Perathoner A, Ladurner R, et al. Prognostic value of indoleamine 2,3-dioxygenase expression in colorectal cancer: effect on tumor-infiltrating T cells[J]. Clin Cancer Res, 2006, 12 (4): 1144-1151.
[63]Ino K, Yoshida N, Kajiyama H, et al. Indoleamine 2,3-dioxygenase is a novel prognostic indicator for endometrial cancer[J]. Br J Cancer, 2006, 95 (11): 1555-1561.
[64]Nakamura T, Shima T, Saeki A, et al. Expression of indoleamine 2, 3-dioxygenase and the recruitment of Foxp3-expressing regulatory T cells in the development and progression of uterine cervical cancer[J]. Cancer Sci, 2007, 98 (6): 874-881.
[65]Uyttenhove C, Pilotte L, Theate I, et al. Evidence for a tumoral immune resistance mechanism based on tryptophan degradation by indoleamine 2,3-dioxygenase[J]. Nature Med, 2003, 9 (7): 1269.
[66]Katharina S, Christiana W, Lothar CF, et al. Tryptophan degradation in patients with gynecological cancer correlates with immune activation[J]. Cancer Lett, 2005, 223: 323.
[67]Munn DH. Expression of indoleamine 2,3-dioxygenase by plasmacytoid dendritic cells in tumor draining lymph nodes[J]. J Clin Invest, 2004, 114: 280.
[68]Fallarino F. Functional expression of indoleamine 2,3-dioxygenase by murine CD8α~+ dendritic cells[J]. Int Immunol, 2002, 14: 65.
[69] Munn DH. Potential regulatory function of human dendritic cells expressing indoleamine 2, 3-dioxygenase[J]. Science, 2002, 297: 867.
[70] Wang CC, Huang YJ, Chen LG, Lee LT, Yang LL. Inducible nitric oxide synthase inhibitors of Chinese herbs III. Rheum palmatum. Planta Med, 2002, 68(10): 869- 874.
[71] Mellor AL, Keskin DB, Johnson T, Chandler P, Munn DH. Cells expressing indoleamine 2,3-dioxygenase inhibit T cell responses[J]. J Immunol, 2002, 168 (8): 3771-3776.
[72] Huang Yanping and Wange RL. T Cell Receptor Signaling: Beyond Complex Complexes[J]. J. Biol. Chem., 2004,279 (28):28827-30.
[73] Perkins ND. Integrating cell-signalling pathways with NF-kB and IKK function[J]. Nat Rev Mol Cell Biol, 2007, 8(1): 49-62.
[74] Whiteside ST and Alain Isra¨el. IkB proteins: structure, function and regulation[J]. seminars in Cancer Biology, 1997, 8: 75-82.
[75] Martin FA. Regulation of dendritic cell migration to the draining lymphnode: impact on T lymphocyte traffic priming[J]. J Exp Med, 2003,198: 615-621.
[76] Reynolds LF, Smyth LA, Norton T, et al. Vavl transduces T cell receptor signals to the activation of phospholipase C-gammal via phosphoinositide 3-kinase- dependent and -independent pathways[J]. J Exp Med, 2002,195 (9): 1103-1114.
[77] Lewis CM, Broussard C, Czar MJ, et al. Tec kinases: modulators of lymphocyte signaling and development[J]. Curr Opin Immunol, 2001, 13 (3): 317-325.
[78] Bauer TM, Jiga LP, Chuang JJ, et al. Studying the immunosuppressive role of indoleamine 2,3-dioxygenase: tryptophan metabolites suppress rat allogeneic T- cell responses in vitro and in vivo[J]. Transpl Int, 2005, 18 (1): 95-100.
[79] Gogishvili T, Elias F, Emery JL, McPherson K, Okkenhaug K, Hünig T, et al. Proliferative signals mediated by CD28 superagonists require the exchange factor Vavl but not phosphoinositide 3-kinase in primary peripheral T cells[J]. Eur J Immunol, 2008, 38 (9): 2528-2533.
[80] Tuosto L, Marinari B, Piccolella E. CD4-Lck through TCR and in the absence of Vav exchange factor induces Bax increase and mitochondrial damage[J]. J Immunol, 2002,168 (12): 6106-6112.
1. Romero F, Fischer S. Structure and function of Vav. Cell Signal, 1996,8(8): 545-553.
2. López-Lago M, Lee H, Cruz C, et al. Tyrosine phosphorylation mediates both activation and downmodulation of the biological activity of Vav. Mol Cell Biol, 2000,20(5):1678-1691.
3. Tybulewicz VL, Ardouin L, Prisco A, et al. Vav1: a key signal transducer downstream of the TCR. Immunol Rev, 2003, 192: 42-52.
4. Chrencik JE, Brooun A, Zhang H. Structural basis of guanine nucleotide exchange mediated by the T-cell essential Vavl. J Mol Biol, 2008, 380(5): 828-843.
5. Rapley J, Tybulewicz VL, Rittinger K. Crucial structural role for the PH and C1 domains of the Vavl exchange factor. EMBO Rep, 2008,9(7):655-661.
6. Tarakhovsky A, Turner M, Schaal S, et al. Defective antigen receptor-mediated proliferation of B and T cells in the absence of Vav. Nature, 1995, 374 (6521): 467-470.
7. Katzav S. Flesh and blood: the story of Vav1, a gene that signals in hematopoietic cells but can be transforming in human malignancies. Cancer Lett, 2007,255(2):241-254.
8. Turner M, Mee PJ, Walters AE, et al. A requirement for the Rho-family GTP exchange factor Vav in positive and negative selection of thymocytes. Immunity, 1997,7 (4): 451-460.
9. Kong YY, Fischer KD, Bachmann MF, et al. Vav regulates peptide-specific apoptosis in thymocytes. J Exp Med, 1998, 188(11): 2099-2111.
10. Gulbranson-Judge A, Tybulewicz VL, Walters AE, et al. Defective immunoglobulin class switching in Vav-deficient mice is attributable to compromised T cell help. Eur J Immunol, 1999,29(2): 477-487.
11. Penninger JM, Fischer KD, Sasaki T, et al. The oncogene product Vav is a crucial regulator of primary cytotoxic T cell responses but has no apparent role in CD28-mediated co-stimulation. Eur J Immunol, 1999, 29(5): 1709-1718.
12. Fischer KD, Kong YY, Nishina H, et al. Vav is a regulator of cytoskeletal reorganization mediated by the T-cell receptor. Curr Biol, 1998, 8(10): 554-562.
13. Costello PS, Walters AE, Mee PJ, et al. The Rho-family GTP exchange factor Vav is a critical transducer of T cell receptor signals to the calcium, ERK, and NF-kappaB pathways. Proc Natl Acad Sci USA, 1999,96(6): 3035-3040.
14. Holsinger LJ, Graef IA, Swat W, et al. Defects in actin-cap formation in Vav-deficient mice implicate an actin requirement for lymphocyte signal transduction. Curr Biol, 1998, 8 (10): 563-572.
15. Reynolds LF, Smyth LA, Norton T, et al. Vavl transduces T cell receptor signals to the activation of phospholipase C-gammal via phosphoinositide 3-kinase-dependent and -independent pathways. J Exp Med, 2002, 195(9):1103-1114.
16. Lewis CM, Broussard C, Czar MJ, et al. Tec kinases: modulators of lymhocyte signaling and development. Curr Opin Immunol, 2001,13(3): 317-325.
17. Reynolds LF, de Bettignies C, Norton T, et al. Vavl transduces T cell receptor signals to the activation of the Ras/ERK pathway via LAT, Sos and RasGRP1. J Biol Chem, 2004, 279(18): 18239-18246.
18. Altaian A, Villalba M. Protein kinase C-theta (PKCtheta): it's all about location, location, location. Immunol Rev, 2003, 192: 53-63.
19. Sánchez-Martín Lorena, Sánchez-Sánchez Noelia, Gutiérrez-Lopez MD, et al. Signaling through the leukocyte integrin LFA-1 in T cells induces a transient activation of Rac-1 that is regulated by Vav and PI3K/Akt-1. J Biol Chem, 2004, 279(16): 16194-16205.
20. Etienne-Manneville S, Hall A. Rho GTPases in cell biology. Nature, 2002, 420 (6916): 629-635.
21. Fischer KD, Tedford K, Penninger JM. Vav links antigen-receptor signaling to the actin cytoskeleton. Semin Immunol, 1998,10 (4): 317-327.
22. Ardouin L, Bracke M, Mathiot A, et al. Vavl transduces TCR signals required for LFA-1 function and cell polarization at the immunological synapse. Eur J Immunol, 2003, 33 (3): 790-797.
23. Houlard M, Arudchandran R, Regnier-Ricard F, et al. Vavl is a component of transcriptionally active complexes. J Exp Med, 2002, 195(9):1115-1127.
24. Baldari CT, Koretzky G, Telford JL, et al. Antigen receptor signalling: the Tuscan chronicles. Nat Immunol, 2005, 6(1):3-5.