Effect of Treg Cells on CD4+Th Immune Responses During Acute FIV Infection

急性 FIV 感染期间 Treg 细胞对 CD4 Th 免疫反应的影响

• 批准号: 7860415
• 负责人: ANGELA M MEXAS
• 金额: $ 12.66万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-07-15 至 2012-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7860415
• 关键词: AIDS/HIV problem; Acute; Antibodies; Antigens; Biological Assay; Biopsy; Blood; CD4 Positive T Lymphocytes; CD80 gene; CD8B1 gene; CTLA4 gene; Cell Count; Cell Proliferation; Cell Separation; Cell physiology; Cell surface; Cells; Chronic; Coculture Techniques; Color; Cytokine Suppression; Data; Enzyme-Linked Immunosorbent Assay; Family Felidae; Feline Immunodeficiency Virus; Felis catus; Flow Cytometry; Future; Gagging; HIV; HIV Infections; Helper-Inducer T-Lymphocyte; IL2RA gene; Immune System Diseases; Immune response; Immune system; Immunosuppression; Immunosuppressive Agents; In Vitro; Infection; Interleukin-2; Measures; Mediator of activation protein; Messenger RNA; Modeling; PTPRC gene; Peripheral Blood Mononuclear Cell; Phase; Phenotype; Plasma; Play; Population; Production; Property; Regulatory T-Lymphocyte; Research Personnel; Resistance; Reverse Transcriptase Polymerase Chain Reaction; Role; SELL gene; Sorting - Cell Movement; Speed; Staging; Staining method; Stains; Surface; T-Lymphocyte; T-Lymphocyte Subsets; TGFB1 gene; Testing; Therapeutic; Thymidine; Time; Viral; Viremia; Virus; Virus Diseases; anergy; cytokine; design; enzyme linked immunospot assay; in vivo; lymph nodes; research study; response; time interval

DESCRIPTION (provided by applicant): Evidence suggests that HIV persistence may result from its ability to irreversibly damage the acquired immune system shortly after infection is established. CD4+CD25+ T regulatory (Treg) cells with T cell immunosuppressive properties are possible mediators of this early T cell immune dysfunction. CD4+CD25+ Treg cells harbor a productive virus infection in HIV infected people and FIV infected cats, and are activated for potent immunosuppressor function in vivo. While CD4+CD25+ Treg cells have been shown to play a role in regulating CD4+ and CD8+ immune responses against HIV and FIV antigens in vitro, it is not known at what time following infection these cells become infected and activated or what effect they might have on the early protective T cell immune response. To determine the role of Treg cells in the immunopathogenesis of HIV infection we propose to utilize the FIV model to test our hypothesis that CD4+CD25+ Treg cells become infected and activated during the acute stage of FIV infection leading to the immunosuppression of CD4+ T helper (Th) cell anti-FIV responses. Cats will be experimentally infected with the NCSU-1 isolate of FIV and blood and lymph node biopsies will be collected at 1 week intervals following inoculation. Real-Time PCR and anti-FIV-gag intracellular staining will be used to determine the time of infection, number of copies of the virus and absolute numbers of CD4+CD25+ and CD4+CD25- infected T cells. These data will be correlated with plasma viremia levels as detected by RT-PCR. Flow cytometry and cell sorting will assess the expression of phenotypic activation markers (CD80, CD86 and CTLA4) and markers for regulatory function (FoxP3, TGF?1) in infected and non-infected CD4+CD25+ and CD4+CD25- T cell subsets at different time points during the acute phase of infection. In addition, experiments will be designed to assess changes in the suppressive function of CD4+CD25+ Treg cells on target CD4+ Th cell immune responses, such as IL-2 and IFN-y production and cell proliferation. In vitro infection of CD4+CD25- and CD4+CD25+ T cell populations will be used to corroborate the results obtained from in vivo studies. HIV is currently estimated to infect more than 37 million people worldwide. FIV is a well established model of HIV/AIDS. The results of these experiments will have implications in future therapeutic strategies against HIV and FIV, and contribute to our current understanding of Treg cell function.

描述（由申请人提供）：证据表明，艾滋病毒持久性可能是由于其在感染后不久不可逆地损害获得性免疫系统的能力。具有T细胞免疫抑制特性的CD 4 + CD 25 + T调节（Treg）细胞是这种早期T细胞免疫功能障碍的可能介质。CD 4 + CD 25 + Treg细胞在HIV感染的人和FIV感染的猫中具有生产性病毒感染，并且被激活以在体内发挥有效的免疫抑制功能。虽然CD 4 + CD 25 + Treg细胞已被证明在体外调节针对HIV和FIV抗原的CD 4+和CD 8+免疫应答中起作用，但尚不清楚这些细胞在感染后的什么时间被感染和激活，或者它们可能对早期保护性T细胞免疫应答有什么影响。为了确定调节性T细胞在HIV感染的免疫发病机制中的作用，我们建议利用FIV模型来检验我们的假设，即在FIV感染的急性阶段，CD 4 + CD 25+调节性T细胞被感染并被激活，导致CD 4+辅助性T（Th）细胞抗FIV应答的免疫抑制。将用FIV的NCSU-1分离株对猫进行实验性感染，并在接种后每隔1周采集一次血液和淋巴结活检。将使用实时PCR和抗FIV-gag细胞内染色来确定感染时间、病毒拷贝数以及CD 4 + CD 25+和CD 4 + CD 25-感染T细胞的绝对数。这些数据将与通过RT-PCR检测的血浆病毒血症水平相关。流式细胞术和细胞分选将评估表型活化标志物（CD 80、CD 86和CTLA 4）和调节功能标志物（FoxP 3、TGF？1)在感染和未感染的CD 4 + CD 25+和CD 4 + CD 25- T细胞亚群在感染的急性期的不同时间点。此外，将设计实验以评估CD 4 + CD 25 + Treg细胞对靶CD 4 + Th细胞免疫应答（如IL-2和IFN-γ产生和细胞增殖）的抑制功能的变化。将使用CD 4 + CD 25-和CD 4 + CD 25 + T细胞群的体外感染来证实从体内研究中获得的结果。据估计，目前全世界有3700多万人感染艾滋病毒。FIV是一种公认的艾滋病毒/艾滋病模型。这些实验的结果将对未来针对HIV和FIV的治疗策略产生影响，并有助于我们目前对Treg细胞功能的理解。