组蛋白去乙酰化酶3通过抑制AICD维持T细胞自稳（英文）

为探讨组蛋白去乙酰化酶3(HDAC3)在T细胞自稳中的作用,采用Lox P-cd4cre酶系统在胸腺CD4~+CD8~+双阳性T细胞(DP)中敲除hdac3基因.hdac3基因敲除小鼠不影响T细胞在胸腺中的发育,但导致外周T细胞显著降低,而且,hdac3基因敲除的外周T细胞主要以活化/效应/记忆表型为主.机制分析表明,hdac3基因敲除的外周T细胞凋亡增加并伴随细胞增殖加速,同时,Fas和Fas配体阳性细胞比率以及Fas配体的表达显著增加.体外TCR活化不影响正常外周T细胞的凋亡,但导致hdac3基因敲除的外周T细胞凋亡显著增加.实验结果表明,HDAC3通过抑制活化诱导的细胞凋亡维持外周T细胞自稳.     

组蛋白去乙酰化酶3对外周CD4+ T细胞分化的影响

目的 探讨组蛋白去乙酰化酶3（HDAC3）对外周CD4⁺ T细胞分化及功能的调控作用。方法 采用CD4cre酶介导Hdac3杂合基因缺失小鼠（Hdac3^fl/flCD4^cre+/-）及其野生型正常对照小鼠（Hdac3^fl/fl，WT），流式细胞术检测HDAC3缺失对外周CD4⁺和CD8⁺ T细胞比例和数量的影响；在体外佛波酯（PMA）和离子霉素（Ionomycin）刺激条件下，流式细胞术检测HDAC3缺失对CD4⁺ T细胞中IFN-γ、IL-4和IL-17A的表达以及Tfh细胞产生的影响；采用ELISA检测HDAC3缺失对小鼠血清IFN-γ、IL-4和IL-17表达的影响；分选Hdac3^fl/flCD4^cre+/-和WT小鼠外周初始CD4⁺ T细胞，分别在Th1和Th2分化条件下培养，细胞内染色检测HDAC3缺失对Th1、Th2以及Th17相关细胞因子及其特异转录因子表达的影响；采用Microarray检测HDAC3缺失对CD4⁺ T细胞分化亚群相关基因表达的影响；采用链脲佐菌素（STZ）处理小鼠构建I型糖尿病（TIDM）疾病模型，检测HDAC3缺失对T1DM发病的影响。结果 与WT小鼠相比，Hdac3^fl/flCD4^cre+/-小鼠外周CD4⁺和CD8⁺ T细胞的比例和数量显著降低。Hdac3^fl/flCD4^cre+/-小鼠CD4⁺ T细胞及血清中IFN-γ的表达显著降低，而IL-4和IL-17A的表达显著增加，Tfh细胞比例也显著增加；HDAC3缺失抑制体外培养CD4⁺ T细胞向Th1分化但促进其向Th2分化；Microarray检测发现HDAC3缺失导致Th1型细胞谱系基因表达降低，而Th2、Th17以及Tfh细胞谱系基因表达增加；在STZ诱导条件下，HDAC3缺失抑制小鼠T1DM的发生和CD4⁺ T细胞向Th1分化。结论 HDAC3促进外周CD4⁺ T细胞向Th1细胞分化并加重T1DM的发生。     

胸腺树突状细胞对胸腺细胞凋亡的促进作用

小鼠胸腺细胞在体外培养一定时间后自发出现凋亡,在与小鼠胸腺树突状细胞(MTSC4)共育后,其凋亡过程可被明显加速;与此相反,小鼠胸腺上皮细胞(MTECI)有抑制凋亡的作用.与MTSC4共育后的胸腺细胞中不仅CD4⁺CD8⁺双阳性细胞明显减小,而且CD4⁺CD8⁺单阳性细胞也减少.提示胸腺基质细胞可通过其对细胞凋亡的促进作用参与胸腺内的阴性选择,并提示阴性选择可能在胸腺髓质区仍在进行.     

胸腺T细胞由双阳到单阳分化发育的非线性模型

根据指令与随机相结合模型的理论,建立非线性数学模型,从理论上描述了胸腺内T细胞从双阳到单阳细胞的分化发育过程.发现随着胸腺基质细胞（TSCs）上MHCⅠ位点的增加,CD4⁺8⁺双阳胸腺细胞数量减少,CD4^-8⁺单阳胸腺细胞数增加;随着CD4⁺8⁺细胞与TSCs亲和力的增加,更多的双阳细胞进一步分化为单阳细胞,描述了胸腺基质细胞如何介导胸腺细胞从双阳向单阳分化发育的过程.     

研究报告: 实验性自身免疫性葡萄膜炎模型中肝脏免疫系统紊乱的研究

葡萄膜炎是一种反复发作的炎症性疾病,可导致免疫系统功能障碍和多器官损伤．然而,葡萄膜炎是否导致肝功能损害尚不十分清楚．本文通过运用流式分析技术和激光共聚焦成像技术,研究了实验性自身免疫葡萄膜炎模型的肝脏病理和功能变化．结果显示肝损伤可出现在葡萄膜炎的炎症后期并与眼损伤程度相关．并且CD3⁺ CD4⁺ T细胞、CD3^- NK1.1⁺ DX5^- NK细胞、和CD11b⁺ F4/80^- ly6c⁺ 细胞在感染的眼睛和肝脏中增加．将CD3⁺ CD4⁺ T细胞回输给炎症的小鼠后,眼睛和肝脏的病理损伤加重．此外,在炎症的小鼠中可见血管扩张,大量淋巴细胞浸润到炎症的眼和肝脏的血管周围．总之,我们的研究结果提示,肝损伤可以发生在小鼠葡萄膜炎模型中,这种损伤可能与通过外周循环浸润到肝脏的CD3⁺ CD4⁺ T细胞有关．     

外周血Treg细胞、T淋巴细胞及其亚群与早期宫颈癌的关系及对淋巴结转移的预测价值研究

摘要 目的：分析外周血Treg细胞、T淋巴细胞及其亚群与早期宫颈癌的关系及对淋巴结转移的预测价值。方法：选择我院自2017年1月至2020年12月接诊的60例接受子宫颈癌根治术及盆腔淋巴清扫术的早期宫颈癌患者作为观察组,另选同期的60例健康体检者作为对照组。比较两组外周血Treg细胞、T淋巴细胞及其亚群水平,使用受试者工作特征曲线（ROC）下面积（AUC）评价外周血Treg细胞、T淋巴细胞及其亚群对淋巴结转移的预测效能。结果：观察组外周血Treg细胞、CD8⁺T细胞水平高于对照组,CD3⁺T细胞、CD4⁺T细胞、CD4⁺/CD8⁺比值均低于对照组（P＜0.05）;观察组术后外周血Treg细胞、CD8⁺T细胞水平较术前降低,CD3⁺T细胞、CD4⁺T细胞、CD4⁺/CD8⁺比值均较术前升高（P＜0.05）;在60例早期宫颈癌患者中,发生淋巴结转移12例;淋巴结转移组术前外周血Treg细胞水平、CD8⁺T细胞高于非淋巴结转移组,CD3⁺T细胞、CD4⁺T细胞、CD4⁺/CD8⁺比值均低于非淋巴结转移组（P＜0.05）;经多因素Logistic回归分析,外周血Treg细胞、CD3⁺T细胞、CD4⁺/CD8⁺比值均是早期宫颈癌患者发生淋巴结转移的独立预测因素（P＜0.05）;经ROC曲线分析,外周血Treg细胞、CD3⁺T细胞联合CD4⁺/CD8⁺比值预测早期宫颈癌患者发生淋巴结转移的AUC为0.910。结论：外周血Treg细胞、T淋巴细胞及其亚群水平与早期宫颈癌的病情演变有关,其中外周血Treg细胞、CD3⁺T细胞联合CD4⁺/CD8⁺比值预测淋巴结转移的效能较好,值得进一步研究应用。     

IL-7和胸腺基质细胞系(MTEC5)诱导胸腺CD3- CD4- CD8- 细胞分化

胸腺细胞发育是细胞因子及胸腺细胞与胸腺基质细胞相互作用的结果.观察了IL-7及小鼠胸腺基质上皮细胞系MTEC5对成年小鼠CD3^- CD4^- CD8^- 胸腺细胞发育的影响.IL-7能促进TN细胞增殖.TN细胞经在IL-7条件下培养后表达CD3-TCR分子,其中20％～40％为TCRγδ⁺,60％～80％为TCRαβ⁺,但保持CD4^- CD8^- .该细胞获得对 Con A、抗CD3mAb及抗TCRmAb进行增殖应答的能力,抗CD28mAb能促进这种增殖应答,证明表达的CD3-TCR分子功能成熟.当在该系统中加入MTEC5,部分TN细胞转变为CD3⁺TCRβ⁺CD4⁺CD8^- 和CD3⁺TCRβ⁺CD4^- CD8⁺SP细胞,表明MTEC5可诱导TN细胞分化为表现型成熟的胸腺细胞.     

小细胞肺癌患者外周血淋巴细胞亚群分析

目的探究化疗对小细胞肺癌(small cell lung cancer,SCLC)患者免疫功能的影响。方法选择2013年1月到2018年12月我院收治的95例小细胞肺癌患者为研究对象。患者第一周期、第二周期化疗前采用流式细胞术检测患者外周血淋巴细胞亚群水平,分别按照不同疗效及不同化疗方案对患者外周血淋巴细胞亚群进行比较。结果(1)化疗后,95例患者CD3⁺、CD4⁺、CD8⁺细胞平均值增加,CD19⁺、γδT细胞平均值减少,差异均有统计学意义(均P<0.05)。(2)化疗后,部分缓解组患者CD3⁺、CD8⁺细胞平均值增加,CD19⁺细胞减少,差异有统计学意义(均P<0.05);病情稳定组和病情进展组患者各细胞水平无显著变化(均P>0.05)。(3)依托泊苷联合顺铂(EP)方案组化疗后患者CD3⁺、CD8⁺细胞平均值增多,CD19⁺细胞减少,差异均有统计学意义(均P<0.05);伊立替康联合顺铂(IP)方案和依托泊苷联合卡铂(EC)方案组化疗后患者各细胞水平无显著变化(均P>0.05)。结论化疗可以调节小细胞肺癌患者的免疫功能,增强细胞免疫,降低体液免疫,其中EC方案对患者细胞免疫的增强作用较为显著。     

外周血T细胞CD38和HLA-DR的表达水平在儿童传染性单核细胞增多症中的临床意义

摘要 目的：探讨传染性单核细胞增多症（IM）患儿外周血T细胞活化分子CD38和人类白细胞抗原DR（HLA-DR）表达水平的临床意义。方法：采用流式细胞术分别检测45例IM患儿急性期和恢复期的活化分子CD38和HLA-DR在T细胞的表达水平,并与30例健康体检儿童进行对比。分析IM患儿急性期CD38和HLA-DR在T细胞的表达水平与EB病毒载量、肝功能指标、外周血异型淋巴细胞比例、淋巴细胞计数的相关性,并采用ROC曲线分析CD8⁺CD38⁺T和CD8⁺HLA-DR+T细胞百分比的诊断效能。结果：与对照组比较,IM急性期患儿的CD38和HLA-DR在T细胞的表达水平显著升高（P＜0.05）。CD8⁺CD38⁺T、CD8⁺HLA-DR+T细胞百分比分别与EBV-DNA、ALT、AST、LDH、异型淋巴细胞百分比、淋巴细胞计数呈正相关（P＜0.05）,与白蛋白（ALB）呈负相关（P＜0.05）;CD4⁺CD38⁺T、CD4⁺HLA-DR+T细胞百分比与上述指标无显著相关性（P均＞0.05）。IM恢复期CD38和HLA-DR在T细胞的表达水平较急性期明显降低（P＜0.05）。ROC曲线分析CD8⁺CD38⁺T、CD8⁺HLA-DR+T细胞百分比显示诊断儿童IM的AUC值分别为0.931和0.993,特异度均为100%,灵敏度分别为88.89 %和93.33 %。结论：流式法检测CD38和HLA-DR在T细胞的变化有助于判断病情变化。外周血CD8⁺CD38⁺T、CD8⁺HLA-DR+T细胞百分比不仅能反映出IM急性期肝功能损伤严重程度,还可作为儿童IM的流式诊断指标。     

口服维生素D对实验性脑疟小鼠树突状细胞的影响

维生素D（VD）为固醇类衍生物,除发挥抗佝偻病作用,还具有一定的免疫调节功能。主要研究VD对实验性脑疟小鼠树突状细胞的影响。结果显示,与对照组相比,在伯氏疟原虫（P.bANKA）感染前给予VD,可降低C57BL/6小鼠发生脑型疟疾的风险,存活时间明显延长。VD预处理后,脾脏中髓样树突状细胞（CD11c⁺CD11b⁺）和浆样树突状细胞（CD11c⁺B220⁺）百分率明显降低,CD11c⁺MHCII⁺细胞、CD11c⁺TLR4⁺细胞和CD11c⁺TLR9⁺细胞的百分含量也显著减少。由此提示,预防性口服VD可抑制感染小鼠树突状细胞的数量和功能,对脑型疟疾的发生具有一定预防作用,为新型抗疟药物的研发提供参考。     

HDAC1 Controls CD8+ T Cell Homeostasis and Antiviral Response

Reversible lysine acetylation plays an important role in the regulation of T cell responses. HDAC1 has been shown to control peripheral T helper cells, however the role of HDAC1 in CD8⁺ T cell function remains elusive. By using conditional gene targeting approaches, we show that LckCre-mediated deletion of HDAC1 led to reduced numbers of thymocytes as well as peripheral T cells, and to an increased fraction of CD8⁺CD4^– cells within the CD3/TCRβ^lo population, indicating that HDAC1 is essential for the efficient progression of immature CD8⁺CD4^– cells to the DP stage. Moreover, CD44^hi effector CD8⁺ T cells were enhanced in mice with a T cell-specific deletion of HDAC1 under homeostatic conditions and HDAC1-deficient CD44^hi CD8⁺ T cells produced more IFNγ upon ex vivo PMA/ionomycin stimulation in comparison to wild-type cells. Naïve (CD44^l°CD62L⁺) HDAC1-null CD8⁺ T cells displayed a normal proliferative response, produced similar amounts of IL-2 and TNFα, slightly enhanced amounts of IFNγ, and their in vivo cytotoxicity was normal in the absence of HDAC1. However, T cell-specific loss of HDAC1 led to a reduced anti-viral CD8⁺ T cell response upon LCMV infection and impaired expansion of virus-specific CD8⁺ T cells. Taken together, our data indicate that HDAC1 is required for the efficient generation of thymocytes and peripheral T cells, for proper CD8⁺ T cell homeostasis and for an efficient in vivo expansion and activation of CD8⁺ T cells in response to LCMV infection.     

Tumor-derived Fas ligand induces toxicity in lymphoid organs and plays an important role in successful chemotherapy

 Recent studies have suggested that Fas ligand (FasL⁺) tumor cells can induce apoptosis in Fas⁺ T cells. However, the effect of growth of FasL⁺ tumors in vivo, on lymphoid tissues of the host is not clear and therefore was the subject of this investigation. Injection of FasL⁺ LSA tumor caused a significant decrease in cellularity of the thymus and spleen, resulting from marked apoptosis, in syngeneic C57BL/6+/+ (wild-type) but not C57BL/6-lpr/lpr (Fas-deficient) mice. The tumor-induced toxicity resulted from tumor-derived rather than host-derived FasL, inasmuch as LSA tumor growth in C57BL/6-gld/gld (FasL-defective) mice, induced marked apoptosis and toxicity in the thymus and spleen. The LSA tumor growth induced a significant decrease in the percentage of CD4⁺CD8⁺ T cells in the thymus of C57BL/6+/+ mice and an increase in the percentage of CD4⁺, CD8⁺ and CD4⁻CD8⁻ T cells. Of the four subpopulations tested, the CD4⁺CD8⁺ T cells showed maximum apoptosis. The LSA (FasL⁺) but not P815(FasL⁻) tumor cell lysates and culture supernatants induced marked apoptosis in Fas⁺ thymocytes, when tested both in vitro and in vivo. The LSA-tumor-induced apoptosis in vitro was inhibited by antibodies against FasL or by caspase and other inhibitors of apoptosis. Chemotherapy of LSA-tumor-bearing C57BL/6+/+ mice at advanced stages of tumor growth failed to cure the mice, whereas, more than 80% of LSA-tumor-bearing C57BL/6-lpr/lpr mice, similarly treated, survived. Together, the current study demonstrates that FasL produced by LSA tumor cells is functional in vivo and can cause severe toxicity in lymphoid organs of the host. Also, Fas/FasL interactions may play an important role in the successful chemotherapy of FasL-bearing tumor. Received: 31 August 1999 / Accepted: 12 November 1999     

Defective CD4<Superscript>+</Superscript>CD25<Superscript>+</Superscript>regulatory T cell functioning in collagen-induced arthritis: an important factor in pathogenesis,counter-regulated by endogenous IFN-γ

Mice with a deficiency in IFN-γ or IFN-γ receptor (IFN-γR) are more susceptible to collagen-induced arthritis (CIA), an experimental autoimmune disease that relies on the use of complete Freund's adjuvant (CFA). Here we report that the heightened susceptibility of IFN-γR knock-out (KO) mice is associated with a functional impairment of CD4⁺CD25⁺ T_reg cells. Treatment of wild-type mice with depleting anti-CD25 antibody after CFA-assisted immunisation with collagen type II (CII) significantly accelerated the onset of arthritis and increased the severity of CIA. This is an indication of a role of T_reg cells in the effector phase of CIA. IFN-γR deficiency did not affect the number of CD4⁺CD25⁺ T cells in the central and peripheral lymphoid tissues. In addition, CD4⁺CD25⁺ T cells isolated from naive IFN-γR KO mice had a normal potential to suppress T cell proliferation in vitro. However, after immunisation with CII in CFA, the suppressive activity of CD4⁺CD25⁺ T cells became significantly more impaired in IFN-γR-deficient mice. Moreover, expression of the mRNA for Foxp3, a highly specific marker for T_reg cells, was lower. We further demonstrated that the effect of endogenous IFN-γ, which accounts for more suppressive activity in wild-type mice, concerns both T_reg cells and accessory cells. Our results demonstrate that the decrease in T_reg cell activity in CIA is counter-regulated by endogenous IFN-γ.     

Effector and naturally occurring regulatory T cells display no abnormalities in activation induced cell death in NOD mice

Background

Disturbed peripheral negative regulation might contribute to evolution of autoimmune insulitis in type 1 diabetes. This study evaluates the sensitivity of naïve/effector (Teff) and regulatory T cells (Treg) to activation-induced cell death mediated by Fas cross-linking in NOD and wild-type mice.

Principal Findings

Both effector (CD25⁻, FoxP3⁻) and suppressor (CD25⁺, FoxP3⁺) CD4⁺ T cells are negatively regulated by Fas cross-linking in mixed splenocyte populations of NOD, wild type mice and FoxP3-GFP tranegenes. Proliferation rates and sensitivity to Fas cross-linking are dissociated in Treg cells: fast cycling induced by IL-2 and CD3/CD28 stimulation improve Treg resistance to Fas-ligand (FasL) in both strains. The effector and suppressor CD4⁺ subsets display balanced sensitivity to negative regulation under baseline conditions, IL-2 and CD3/CD28 stimulation, indicating that stimulation does not perturb immune homeostasis in NOD mice. Effective autocrine apoptosis of diabetogenic cells was evident from delayed onset and reduced incidence of adoptive disease transfer into NOD.SCID by CD4⁺CD25⁻ T cells decorated with FasL protein. Treg resistant to Fas-mediated apoptosis retain suppressive activity in vitro. The only detectable differential response was reduced Teff proliferation and upregulation of CD25 following CD3-activation in NOD mice.

Conclusion

These data document negative regulation of effector and suppressor cells by Fas cross-linking and dissociation between sensitivity to apoptosis and proliferation in stimulated Treg. There is no evidence that perturbed AICD in NOD mice initiates or promotes autoimmune insulitis.     

肝癌小鼠外周血及脾脏T淋巴细胞亚群的变化及其意义

目的:观察小鼠原位肝癌模型外周血以及脾脏T淋巴细胞亚群与正常小鼠之间的差异变化,探讨其差异变化的意义。方法:在正常KM小鼠肝脏种植H22细胞,建立小鼠原位模型。采用流式细胞术,以健康正常小鼠为对照,检测肝癌小鼠外周血以及脾脏T淋巴细胞亚群的变化。结果:与健康正常小鼠相比,肝癌小鼠外周血CD4~+T淋巴细胞、CD4~+/CD8~+比例有显著性降低,CD8~+T淋巴细胞显著性升高;脾脏CD3~+、CD4~+T淋巴细胞有显著性降低。结论:小鼠原位肝癌模型外周血以及脾脏T淋巴细胞亚群发生异常,免疫系统紊乱,可以反映小鼠肝癌的发生、发展。     

Effect of Dietary Selenium and Cancer Cell Xenograft on Peripheral T and B Lymphocytes in Adult Nude Mice

Selenium (Se) is known to regulate tumorigenesis and immunity at the nutritional and supranutritional levels. Because the immune system provides critical defenses against cancer and the athymic, immune-deficient NU/J nude mice are known to gradually develop CD8⁺ and CD4⁺ T cells, we investigated whether B and T cell maturation could be modulated by dietary Se and by tumorigenesis in nude mice. Fifteen homozygous nude mice were fed a Se-deficient, Torula yeast basal diet alone (Se−) or supplemented with 0.15 (Se+) or 1.0 (Se++) mg Se/kg (as Na₂SeO₄) for 6 months, followed by a 7-week time course of PC-3 prostate cancer cell xenograft (2 × 10⁶ cells/site, 2 sites/mouse). Here, we show that peripheral B cell levels decreased in nude mice fed the Se −  or Se++ diet and the CD4⁺ T cell levels increased in mice fed the Se++ diet. During the PC-3 cell tumorigenesis, dietary Se status did not affect peripheral CD4⁺ or CD8⁺ T cells in nude mice whereas mice fed with the Se++ diet appeared to exhibit greater peripheral CD25⁺CD4⁺ T cells on day 9. Dietary Se status did not affect spleen weight in nude mice 7 weeks after the xenograft. Spleen weight was associated with frequency of peripheral CD4⁺, but not CD8⁺ T cells. Taken together, dietary Se at the nutritional and supranutritional levels regulates peripheral B and T cells in adult nude mice before and after xenograft with PC-3 prostate cancer cells.     

Activation of natural killer T cells inhibits the development of induced regulatory T cells via IFNγ

Recent reports have provided evidence for cross-talk between regulatory T (Treg) cells and natural killer T (NKT) cells. However, it is unclear whether NKT cells play a role in the differentiation of Treg cells. By employing NKT cell-abundant Vα14 TCR transgenic (Tg) and NKT cell-deficient CD1d knock-out (KO) mice, we examined the effects of NKT cells on the in vitro differentiation of induced Treg (iTreg) cells with IL2 and TGFβ. We found that iTreg induction from CD1d KO mice was significantly increased compared to the control. Also, the addition of isolated NKT cells from Vα14 TCR Tg mice to naïve CD4⁺ T cells from CD1d KO mice during iTreg differentiation caused a remarkable reduction of iTreg cells. Through IFNγ neutralization, we showed that this reduction was mediated by IFNγ. Furthermore, the main source of IFNγ during iTreg differentiation was NK1.1⁻CD4⁺Foxp3⁻ T cells. This finding implied that early-activated NKT cells induced Th1-type cells and subsequently underwent apoptosis. Taken together, our results suggest that NKT cells inhibit the in vitro development of iTreg cells by increasing IFNγ.     

Alternatively Activated Mononuclear Phagocytes from the Skin Site of Infection and the Impact of IL-4Rα Signalling on CD4+T Cell Survival in Draining Lymph Nodes after Repeated Exposure to Schistosoma mansoni Cercariae

In a murine model of repeated exposure of the skin to infective Schistosoma mansoni cercariae, events leading to the priming of CD4 cells in the skin draining lymph nodes were examined. The dermal exudate cell (DEC) population recovered from repeatedly (4x) exposed skin contained an influx of mononuclear phagocytes comprising three distinct populations according to their differential expression of F4/80 and MHC-II. As determined by gene expression analysis, all three DEC populations (F4/80^-MHC-II^high, F4/80⁺MHC-II^high, F4/80⁺MHC-II^int) exhibited major up-regulation of genes associated with alternative activation. The gene encoding RELMα (hallmark of alternatively activated cells) was highly up-regulated in all three DEC populations. However, in 4x infected mice deficient in RELMα, there was no change in the extent of inflammation at the skin infection site compared to 4x infected wild-type cohorts, nor was there a difference in the abundance of different mononuclear phagocyte DEC populations. The absence of RELMα resulted in greater numbers of CD4⁺ cells in the skin draining lymph nodes (sdLN) of 4x infected mice, although they remained hypo-responsive. Using mice deficient for IL-4Rα, in which alternative activation is compromised, we show that after repeated schistosome infection, levels of regulatory IL-10 in the skin were reduced, accompanied by increased numbers of MHC-II^high cells and CD4⁺ T cells in the skin. There were also increased numbers of CD4⁺ T cells in the sdLN in the absence of IL-4Rα compared to cells from singly infected mice. Although their ability to proliferate was still compromised, increased cellularity of sdLN from 4x IL-4RαKO mice correlated with reduced expression of Fas/FasL, resulting in decreased apoptosis and cell death but increased numbers of viable CD4⁺ T cells. This study highlights a mechanism through which IL-4Rα may regulate the immune system through the induction of IL-10 and regulation of Fas/FasL mediated cell death.     

Decrease in pool of T lymphocytes with surface phenotypes of effector and central memory cells under Influence of TCR transgenic β-chain expression

Peripheral T lymphocytes can be subdivided into naive and antigen-experienced T cells. The latter, in turn, are represented by effector and central memory cells that are identified by different profiles of activation markers expression, such as CD44 and CD62L in mice. These markers determine different traffic of T lymphocytes in the organism, but hardly reproduce real antigenic experience of a T lymphocyte. Mechanisms of homeostasis maintenance of T lymphocytes with different activation phenotypes remain largely unknown. To investigate impact of T cell receptor (TCR) transgenic chains on formation of T lymphocytes, their peripheral survival and activation surface phenotypes, we have generated the transgenic mouse strain expressing transgenic β-chain of TCR 1D1 (belonging to the Vβ6 family) on the genetic background B10.D2(R101). Intrathymic development of T cells in these transgenic mice is not impaired. The repertoire of peripheral T lymphocytes in these mice contains 70–80% of T cells expressing transgenic β-chain and 20–30% of T cells expressing endogenous β-chains. The ratio of peripheral CD4⁺CD8^? and CD4^?CD8⁺ T lymphocytes remained unchanged in the transgenic animals, but the percent of T lymphocytes with the “naive” phenotype CD44^?CD62L⁺ was significantly increased, whereas the levels of effector memory CD44⁺CD62L^? and central memory CD44⁺CD62L⁺ T lymphocytes were markedly decreased in both subpopulations. On the contrary, T lymphocytes expressing endogenous β-chains had surface phenotype of activated T cells CD44⁺. Thus, for the first time we have shown that the pool of T lymphocytes with different activation phenotypes depends on the structure of T cell receptors.     

Indirubin modulates CD4+ T‐cell homeostasis via PD1/PTEN/AKT signalling pathway in immune thrombocytopenia

Immune thrombocytopenia (ITP) is an acquired autoimmune disease characterized by an immune mediated decrease in platelet number. Disturbance of CD4⁺ T‐cell homeostasis with simultaneous decrease of CD4⁺CD25⁺Foxp3⁺ regulatory T cells (Tregs) as well as unrestricted proliferation and activation of peripheral CD4⁺ effector T cells underpin the pathophysiology of ITP. Indirubin is an active ingredient of a traditional Chinese herb called Indigofera tinctoria L. which is clinically used for the treatment of ITP patients. Whether indirubin targets the Tregs/effector T cell‐axis to restore platelet number is unknown. In our in vitro studies, Indirubin could significantly enhance the number and function of Tregs and meanwhile dampen the activation of effector T cells in a dose‐dependent manner. Indirubin was observed to restore the expression of programmed cell‐death 1 (PD1) and phosphatase and tensin homolog (PTEN) on the CD4⁺ T cells of ITP patients, leading to the subsequent attenuation of the AKT/mTOR pathway. Furthermore, these observations were recapitulated in an active murine model of ITP with a prominent platelet response. Thus, our results identified a potentially novel mechanism of the therapeutic action of indirubin in the treatment of ITP through regulating the homeostasis of CD4⁺ T cells in a PD1/PTEN/AKT signalling pathway.