Two subsets of naive T helper cells with distinct T cell receptor excision circle content in human adult peripheral blood

During ageing thymic function declines and is unable to meet the demand for peripheral T helper (Th) cell replenishment. Therefore, population maintenance of naive Th cells must be at least partly peripherally based. Such peripheral postthymic expansion of recent thymic emigrants (RTEs) during ageing consequently should lead to loss or dilution of T cell receptor excision circles (TRECs) from a subset of naive T cells. We have identified two subsets of naive Th cells in human adult peripheral blood characterized by a striking unequal content of TRECs, indicating different peripheral proliferative histories. TRECs are highly enriched in peripheral naive CD45RA(+) Th cells coexpressing CD31 compared with peripheral naive CD45RA(+) Th cells lacking CD31 expression, in which TRECs can hardly be detected. Furthermore we show that CD31(-)CD45RA(+) Th cells account for increasing percentages of the naive peripheral Th cell pool during ageing but retain phenotypic and functional features of naive Th cells. As CD31 is lost upon T cell receptor (TCR) engagement in vitro, we hypothesize that TCR triggering is a prerequisite for homeostatically driven peripheral postthymic expansion of human naive RTEs. We describe here the identification of peripherally expanded naive Th cells in human adult blood characterized by the loss of CD31 expression and a highly reduced TREC content.     

Functional Th1-oriented T follicular helper cells that infiltrate human breast cancer promote effective adaptive immunity

We previously demonstrated that tumor-infiltrating lymphocytes (TIL) in human breast cancer sometimes form organized tertiary lymphoid structures (TLS) characterized by CXCL13-producing T follicular helper (Tfh) cells. The present study found that CD4⁺ Tfh TIL, CD8⁺ TIL, and TIL-B, colocalizing in TLS, all express the CXCL13 receptor CXCR5. An ex vivo functional assay determined that only activated, functional Th1-oriented Tfh TIL (PD-1^hiICOS^int phenotype) provide help for immunoglobulin and IFN-γ production. A functional Tfh TIL presence signals an active TLS, characterized by humoral (immunoglobulins, Ki-67⁺ TIL-B in active germinal centers) and cytotoxic (GZMB⁺CD8⁺ and GZMB⁺CD68⁺ TIL plus Th1 gene expression) immune responses. Analysis of active versus inactive TLS in untreated patients revealed that the former are associated with positive clinical outcomes. TLS also contain functional T follicular regulatory (Tfr) TIL, which are characterized by a CD25⁺CXCR5⁺GARP⁺FOXP3⁺ phenotype and a demethylated FOXP3 gene. Functional Tfr inhibited functional Tfh activities via a glycoprotein A repetitions predominant (GARP)-associated TGF-β–dependent mechanism. The activity of tumor-associated TLS was dictated by the relative balance between functional Tfh TIL and functional Tfr TIL. These data provide mechanistic insight into TLS processes orchestrated by functional Th1-oriented Tfh TIL, including TIL-B and CD8⁺ TIL activation and immunological memory generation. Tfh TIL, regulated by functional Tfr TIL, are an expected key target of PD-1/PD-L1 blockade.     

Peanut allergy: Beyond the oral immunotherapy plateau

BackgroundThere are a lack of disease‐modifying treatments for peanut allergy, which is lifelong in most instances. Oral immunotherapy has remained at the forefront of prospective treatments, though its efficacy is consistently undermined by the risk of adverse reactions and meager sustained effects.AimThis review discusses the current state of oral immunotherapy, its strengths and limitations, and the future of therapeutics for the treatment of peanut allergy.ConclusionThe persistence of peanut allergy is currently attributed to reservoirs of peanut‐specific memory B cells and Th2 cells, though the cellular and molecular interplay that facilitates the replenishment of peanut‐specific IgE remains elusive. Uncovering these events will prove critical for identification of novel targets as we forge ahead to a new age of peanut allergy treatment with biotherapeutics.     

舌下含服粉尘螨滴剂脱敏治疗对特应性皮炎患者中辅助性T细胞作用的研究

目的 探讨舌下含服粉尘螨滴剂脱敏治疗对特应性皮炎(atopic dermatitis,AD)患者辅助性T细胞(T helper cells,Th)的作用.方法 用酶联免疫吸附测定(enzyme-linked immuno sorbent assay,ELISA)方法检测AD患者舌下含服粉尘螨滴剂组(sublingual immunotherapy,SLIT组)和对照组治疗前后的外周血Th1(IFN-γ)、Th2(IL-4)、Th17(IL-17)的水平,用流式细胞技术检测两组治疗前后的调节性T细胞(regulatoryT cells,Treg)数量.然后用两独立样本t或校正t(t')检验对两组患者治疗前和治疗后的组内以及治疗后组间的IFN-γ、IL-4、IL-17和Treg水平分别进行对比研究.结果 SLIT组治疗后IL-4、IL-17较治疗前明显下降,IFN-γ和Treg较治疗前明显升高,差异有统计学意义(P＜0.05).且SLIT组治疗后较对照组治疗后IL-4、IL-17下降更明显,IFN-γ升高更明显,差异有统计学意义(P＜0.05).SLIT组治疗后Treg细胞数量较对照组治疗后升高更多,但差异无统计学意义(P＞0.05).结论 在AD患者中,舌下含服粉尘螨滴剂治疗能降低其外周血IL-4、IL-17,升高IFN-γ和Treg水平而达到治疗的目的.     

Early T follicular helper cell activity accelerates hepatitis C virus-specific B cell expansion

Early appearance of neutralizing antibodies during acute hepatitis C virus (HCV) infection is associated with spontaneous viral clearance. However, the longitudinal changes in antigen-specific memory B cell (MBCs) associated with divergent HCV infection outcomes remain undefined. We characterized longitudinal changes in E2 glycoprotein-specific MBCs from subjects who either spontaneously resolved acute HCV infection or progressed to chronic infection, using single-cell RNA-seq and functional assays. HCV-specific antibodies in plasma from chronically infected subjects recognized multiple E2 genotypes, while those from spontaneous resolvers exhibited variable cross-reactivity to heterotypic E2. E2-specific MBCs from spontaneous resolvers peaked early after infection (4–6 months), following expansion of activated circulating T follicular helper cells (cTfh) expressing interleukin 21. In contrast, E2-specific MBCs from chronically infected subjects, enriched in VH1-69, expanded during persistent infection (> 1 year), in the absence of significantly activated cTfh expansion. Early E2-specific MBCs from spontaneous resolvers produced monoclonal antibodies (mAbs) with fewer somatic hypermutations and lower E2 binding but similar neutralization as mAbs from late E2-specific MBCs of chronically infected subjects. These findings indicate that early cTfh activity accelerates expansion of E2-specific MBCs during acute infection, which might contribute to spontaneous clearance of HCV.     

肿瘤病人T细胞核仁嗜银蛋白和辅助性T细胞亚群变化

目的:探讨肿瘤病人外周血单个核细胞(PBMC)中T细胞核仁嗜银蛋白(AgNORs)变化和辅助性T(Th)细胞亚群变化的关系及其临床意义。方法PBMC经多克隆T细胞活化剂刺激,以图像分析法检测AgNORs区面积与细胞核仁面积的百分比(1.S％):PBMC被离子霉素和佛波醇酯活化5h后,以酶联免疫斑点法(ELISPOT)检测IFNY、和IL-4产生细胞的频度(％):以离子霉素加佛波醇酯刺激24h,用ELISA试刑盒检测培养上清液中的IFNY、和IL-4水平。结果 肿瘤病人(n=86)和正常人(n=44),PBMC中活化T细胞的AgNORs表达分别为4.9±1.21.S％和.7.82±1.28 1.S％,肿瘤组非常显著下降,P<0.05:肿瘤组PBMC中1112细胞额度显著上升,Th1／Th2比值显著下降:同时,肿瘤组PBMC产生IFN和IL-4水平发生相应变化,变化方式与Th亚群变化相似:在肺癌组中,转移的与未转移的,复发的与未复发的相比,Th1细胞数、Th1／Th2之比和IFNY、产生水平非常显著下降:在肿瘤组AgNORs表达与Th1细胞频度、Th1／Th2比值、IFNY产生和肿瘤病人生活状态的Kamofsky评分正相关。结论 现有病例观察结果表明,肿瘤病人PBMC小T细胞表达AgNORs下降,与患者Th1细胞功能下降正相关。     

Dynamic single-cell RNA sequencing identifies immunotherapy persister cells following PD-1 blockade

Resistance to oncogene-targeted therapies involves discrete drug-tolerant persister cells, originally discovered through in vitro assays. Whether a similar phenomenon limits efficacy of programmed cell death 1 (PD-1) blockade is poorly understood. Here, we performed dynamic single-cell RNA-Seq of murine organotypic tumor spheroids undergoing PD-1 blockade, identifying a discrete subpopulation of immunotherapy persister cells (IPCs) that resisted CD8⁺ T cell–mediated killing. These cells expressed Snai1 and stem cell antigen 1 (Sca-1) and exhibited hybrid epithelial-mesenchymal features characteristic of a stem cell–like state. IPCs were expanded by IL-6 but were vulnerable to TNF-α–induced cytotoxicity, relying on baculoviral IAP repeat-containing protein 2 (Birc2) and Birc3 as survival factors. Combining PD-1 blockade with Birc2/3 antagonism in mice reduced IPCs and enhanced tumor cell killing in vivo, resulting in durable responsiveness that matched TNF cytotoxicity thresholds in vitro. Together, these data demonstrate the power of high-resolution functional ex vivo profiling to uncover fundamental mechanisms of immune escape from durable anti–PD-1 responses, while identifying IPCs as a cancer cell subpopulation targetable by specific therapeutic combinations.     

Two distinct types of helper T cells involved in the secondary antibody response: independent and synergistic effects of Ia- and Ia+ helper T cells.

We have described here two distinct types of carrier-specific helper T cells which act independently and synergistically to augment the B-cell response to a hapten. They are separable by passage through a nylon wool column. The first type of helper T cell, which we designate as Th1, is nylon nonadherent, and can help the response of hapten-primed B cells only if the haptenic and carrier determinants are present on a single molecule (cognate interaction). The second type of helper T cell, Th2, adheres to the nylon wool column, and can help the B-cell response to a hapten coupled to a heterologous carrier upon stimulation with unconjugated relevant carrier (polyclonal interaction). The addition of a small number of Th2 to the mixture of Th1 and B cells significantly augmented the net response to the hapten carrier conjugate. Both Th1 and Th2 cells belong to the Lyt-1+,2-,3- subclass. Th1 has no detectable Ia antigen, whereas Th2 is killed by certain anti-Ia antisera and complement. The Ia antigen detected on Th2 was found to be controlled by a locus in the I-J subregion. The results clearly established the fact that there are two distinct pathways in the T- and B-cell collaboration, which involves two different subsets of carrier-specific helper T cells.     

A cloned major histocompatibility complex-restricted trinitrophenyl-reactive human helper T cell line that activates B cell subsets via two distinct pathways

A cloned, trinitrophenyl (TNP)-specific helper T cell line (TCL), termed E-11, has been established in long-term, interleukin 2-dependent culture and used to study human T helper (Th)-B cell collaboration. Co- culture of E-11 with TNP-modified, but not unmodified or FITC-modified, autologous B cells results in a vigorous, polyclonally plaque-forming cell (PFC) response. E-11 helper activity is not constitutive, but requires antigen-specific, major histocompatibility complex-restricted activation of the TCL cells by interaction with TNP-modified autologous or DR 5+ allogeneic macrophages. Using B cell subsets isolated by discontinuous density gradient cengrifugation as responder populations, we determined that E-11 activates B cell subsets via two distinct mechanisms: (a) E-11 polyclonally activates large B cells in an unrestricted and nonspecific manner; and (b) E-11 preferentially induces a PFC response by TNP-modified small B cells. These results suggest that the large B cell subset is activated by helper signals generated during the Th-antigen-presenting cell interaction, while small B cells require an additional stimulus that is provided by antigen-specific Th-B cell contact.     

肿瘤病人T细胞核仁嗜银蛋白和辅助性T细胞亚群变化

目的　探讨肿瘤病人外周血单个核细胞 (PBMC)中T细胞核仁嗜银蛋白 (AgNORs)变化和辅助性T(Th)细胞亚群变化的关系及其临床意义。方法　PBMC经多克隆T细胞活化剂刺激 ,以图像分析法检测AgNORs区面积与细胞核仁面积的百分比 (I.S % ) ;PBMC被离子霉素和佛波醇酯活化 5h后 ,以酶联免疫斑点法 (ELISPOT)检测γ干扰素 (IFNγ)和白细胞介素 4(IL 4)产生细胞的频度( % ) ;以离子霉素加佛波醇酯刺激 2 4h ,用ELISA试剂盒检测培养上清液中的IFNγ 和IL 4水平。结果86例肿瘤病人和 44名正常人 ,PBMC中活化T细胞AgNORs表达分别为 ( 4 90± 1 2 0 )I S %和 ( 7 82±1 2 8)I S % ,肿瘤组下降非常显著 (P <0 0 5 ) ;肿瘤组PBMC中Th2细胞频度显著上升 ,Th/Th2比值显著下降 ;同时 ,肿瘤组PBMC产生IFNγ 和IL 4水平发生相应变化 ,变化方式与Th亚群变化相似 ;肺癌转移组与未转移组、复发组与未复发组相比 ,Th1细胞数、Th1/Th2之比和IFNγ 的产生下降非常显著 ;在肿瘤组AgNORs表达与Th1细胞频度、Th1/Th2比值、IFNγ 产生和肿瘤病人生活质量评分呈正相关。结论　肿瘤病人PBMC中T细胞表达AgNORs下降 ,与患者Th1细胞功能下降呈正相关。     

突发性耳聋患者外周血T细胞亚群的变化

目的探讨突发性耳聋患者外周血中T细胞亚群的变化情况。方法采用流式细胞术测定43例突发性耳聋患者外周血T细胞亚群数,并与20例健康对照进行比较。结果突发性耳聋组CD+3T细胞、CD+4T细胞、CD+8T细胞以及CD+4/CD+8分别为67.91±4.99、36.98±4.38、30.96±4.03、1.22±0.31。与对照组比较,CD+3T细胞(P=0.062)、CD+4T细胞(P=0.013)和CD+4/CD+8值(P=0.007)呈不同程度降低;CD+8T细胞(P=0.005)、CD+4T细胞(P=0.032)和CD+4/CD+8值(P=0.006)较治疗前呈不同程度升高,CD+8T细胞(P=0.020)。结论突发性耳聋的发病与T细胞亚群数的变化有关,即与机体免疫功能有关。     

类风湿关节炎患者Th亚群在其发病机制中的作用

目的在单细胞水平上研究类风湿关节炎 (RA)患者滑液及外周血中 Th1/Th2细胞因子模式,探讨 Th亚群在 RA发病机制中的作用和意义. 方法15例 RA患者的滑液单个核细胞 (SFMC)和外周血单个核细胞 (PBMC) 及 10例正常人的 PBMC用 PMA离子霉素和莫能菌素刺激培养 6 h,细胞内细胞因子免疫荧光双标染色后,用流式细胞仪检测 Th亚群. 结果与 PBMC[Th1, Th2, Th0分别为( 8.1± 2.1)%,( 2.8± 1.0)%,( 1.8± 0.5)% ]相比, RA患者 SFMC中 Th1和 Th0的比例明显增高 [Th1( 29.2± 3.9)%, Th0( 4.0± 1.4)% ],而 Th2则明显降低 [(1.2± 0.6)% ]; RA患者和正常人 PBMC中, Th1,Th2,Th0差异均无显著性意义 [正常人 Th1, Th2, Th0分别为( 7.3± 2.2)%,( 3.4± 1.1)%,( 2.1± 0.8)% ]. 结论RA患者关节内存在 Th亚群的不平衡, Th1和 Th0占明显优势, Th2则明显减少,恢复 Th1/Th2平衡对 RA的疾病进程和治疗将有重要意义.     

mTOR regulates T cell exhaustion and PD-1–targeted immunotherapy response during chronic viral infection

T cell exhaustion is a state of T cell dysfunction associated with expression of programmed death 1 (PD-1). Exhausted CD8⁺ T cells are maintained by self-renewing stem-like T cells that provide differentiated TIM3⁺ cells, a part of which possesses effector-like properties. PD-1–targeted therapies enhance T cell response by promoting differentiation of stem-like T cells toward TIM3⁺ cells, but the role of mTOR during T cell exhaustion remains elusive. Here, we showed that mTOR inhibition has distinct outcomes during the beginning of and after the establishment of chronic viral infection. Blocking mTOR during the T cell expansion phase enhanced the T cell response by causing accumulation of stem-like T cells, leading to improved efficacy of PD-1 immunotherapy; whereas, after exhaustion progressed, mTOR inhibition caused immunosuppression, characterized by decreased TIM3⁺ cells and increased viral load with minimal changes in stem-like T cells. Mechanistically, a cell-intrinsic mTOR signal was vital for differentiation of stem-like T cells into the TIM3⁺ state in the early and late phases of chronic infection as well as during PD-1 immunotherapy. Thus, PD-1 blockade worked after cessation of mTOR inhibition, but simultaneous treatment failed to induce functional TIM3⁺ cells, reducing efficacy of PD-1 immunotherapy. Our data demonstrate that mTOR regulates T cell exhaustion and have important implications for combination cancer therapies with PD-1 blockade.     

Antigen-binding T cells as helper cells. Separation of helper cells by immune rosette formation

The spleen T cells from mice immunized 6 days earlier with either chicken gamma globulin (CGG) or with donkey erythrocytes (DRC) were rosetted with CGG-coated sheep erythrocytes or with DRC. The immune rosettes (RFC) (antigen-binding cells) were separated from the bulk of nonrosette-forming cells (non-RFC) by 1-g velocity sedimentation and the RFC and non-RFC tested for helper activity in cooperative antihapten responses in vitro. RFC or non-RFC were mixed with normal or hapten-primed spleen cells, challenged with the appropriate hapten-carrier conjugate and cultured for 4 days in Marbrook tissue cultures. The helping activity was quantitated from the numbers of antihapten antibody-producing cells generated per culture. The results show that specific helper cell activity could be selectively recovered in the immune rosette-forming cell population whereas the non-RFC population was depleted of help. These findings indicate that the helper T cells express specific antigen binding receptors.