以T细胞受体为基础的免疫疗法研究进展

T细胞是机体抗肿瘤免疫的核心,以T细胞功能调控为基础的免疫检查点疗法已经在多种肿瘤的临床治疗中取得了重大突破,以基因工程化T细胞为基础的过继性免疫细胞疗法在血液瘤治疗中取得了重要进展,免疫治疗已经对肿瘤的临床治疗产生了深刻变革,成为肿瘤临床治疗策略的重要组成部分。T细胞受体（T cell receptor,TCR）赋予了T细胞识别肿瘤抗原的特异性,能够识别由主要组织相容性复合体（major histocompatibility complex,MHC）呈递的包括胞内抗原在内的广泛肿瘤抗原,具有高度的抗原敏感性,因而具有广泛的抗肿瘤应用前景。2022年第一款TCR药物的上市开启了TCR药物开发的新纪元,多项TCR药物临床研究表现出潜在的肿瘤治疗价值。本文综述了以TCR为基础的免疫治疗策略研究进展,包括T细胞受体工程化T细胞（T cell receptor-engineered T cell,TCR-T）和TCR蛋白药物,以及基于TCR信号的其他免疫细胞疗法,以期为以TCR为基础的免疫治疗策略开发提供参考。     

Lysis protein T of bacteriophage T4

Summary Lysis protein T of phage T4 is required to allow the phage's lysozyme to reach the murein layer of the cell envelope and cause lysis. Using fusions of the cloned gene t with that of the Escherichia coli alkaline phosphatase or a fragment of the gene for the outer membrane protein OmpA, it was possible to identify T as an integral protein of the plasma membrane. The protein was present in the membrane as a homooligomer and was active at very low cellular concentrations. Expression of the cloned gene t was lethal without causing gross leakiness of the membrane. The functional equivalent of T in phage is protein S. An amber mutant of gene S can be complemented by gene t, although neither protein R of (the functional equivalent of T4 lysozyme) nor S possess any sequence similarity with their T4 counterparts. The murein-degrading enzymes (including that of phage P22) have in common a relatively small size (molecular masses of ca. 18 000) and a rather basic nature not exhibited by other E. coli cystosolic proteins. The results suggest that T acts as a pore that is specific for this type of enzyme.     

Self-nonself discrimination by T lymphocytes

Tolerance of T lymphocytes to self-antigens is mainly achieved at the level of the primary lymphoid organ, the thymus, and probably to a lesser extent in the secondary lymphoid tissues. Whether self-reactive lymphocytes ignore their target autoantigen, or are tolerized by the various mechanisms discussed, depends on the circumstances.     

创伤小鼠血清,巨噬细胞,Ts细胞对反抑制T细胞的影响

研究了创伤小鼠反抑制T细胞(Tcs)比例、功能的变化及创伤血清、巨噬细胞、抑制性T细胞(Ts)对正常小鼠Tcs细胞的影响。结果表明,创伤小鼠脾细胞中VVL~ 细胞百分率于伤后一过性减少,Tcs细胞在T淋转、IL-2、IL-2R检测系统中的反抑制活性均明显受抑;创伤小鼠血清、巨噬细胞、Ts细胞在体外对正常Tcs细胞反抑制活性(T淋转、IL-2、IL-2R检测系统)均具有不同程度的抑制作用,创伤后4天小鼠血清在体内对正常小鼠脾脏VVL~ 细胞百分率无明显影响,但可明显降低正常小鼠Tcs细胞的反抑制活性。表明创伤可致Tcs细胞比例及功能发生改变,创伤后血清、巨噬细胞、Ts细胞参与介导了Tcs细胞功能的受抑过程。     

心衰病人的血清T3,T4测定及其意义

目的探讨心衰患者血清Ｔ３、Ｔ４的含量及其临床意义。方法应用放射免疫法测定心衰患者血清Ｔ３、Ｔ４水平５０例,并与３０例病因基本相同心功能代偿者作对照。结果重度心衰者Ｔ３、Ｔ４水平明显下降,与对照组对比差异有显著性（Ｐ＜０．０５）。结论血清Ｔ３、Ｔ４水平与病人预后密切相关,可作为判断病人病情严重程度及临床疗效的综合指标之一。     

Structural chromosome differentiation between Triticum timopheevii and T. turgidum and T. aestivum

 Chromosome pairing at metaphase-I was analyzed in F₁ hybrids among T. turgidum (AABB), T. aestivum (AABBDD), and T. timopheevii (A^tA^tGG) to study the chromosome structure of T. timopheevii relative to durum (T. turgidum) and bread (T. aestivum) wheats. Individual chromosomes and their arms were identified by means of C-banding. Homologous pairing between the A-genome chromosomes was similar in the three hybrid types AA^tBG, AA^tBGD, and AABBD. However, associations of B-G were less frequent than B-B. Homoeologous associations were also observed, especially in the AA^tBGD hybrids. T. timopheevii chromosomes 1A^t, 2A^t, 5A^t, 7A^t, 2G, 3G, 5G, and 6G do not differ structurally from their counterpart in the A and B genomes. Thus, these three polyploid species inherited translocation 5AL/4AL from the diploid A-genome donor. Chromosome rearrangements that occurred at the tetraploid level were different in T. turgidum and T. timopheevii. Translocation 4AL/7BS and a pericentric inversion of chromosome 4A originated only in the T. turgidum lineage. The two lines of T. timophevii studied carry four different translocations, 6A^tS/1GS, 1GS/4GS, 4GS/4A^tL, and 4A^tL/3A^tL, which most likely arose in that sequence. These structural differences support a diphyletic origin of polyploid wheats. Received: 15 June 1998 / Accepted: 19 August 1998     

Vdelta1+ T cells are crucial for repertoire formation of gammadelta T cells in the lung

The pulmonary resident T lymphocytes (RPLs) expressing a nearly invariant T cell receptor γδ heterodimer (γδTCR) migrate from fetal thymus to the lung epithlium, followed by RPL subsets expressing diverse sets of γδTCRs after birth. However, it remains unclear whether the fetal type Vγ6/Vδ1⁺ RPLs are essential for γδ T cell repertoire formation in the lung epithelium. In this study, we found a marked decrease in the number of γδRPLs at 4 weeks of age in Vδ1^−/− mice and they predominantly expressed Vγ6 and Vδ4 genes. The skewed diversity towards the Vδ4-(Dδ1)-Dδ2-Jδ2 junctional region was observed only in γδ RPLs from 4-week-old Vδ1^−/− mice, compared with those from 8-week-old Vδ1^−/− mice and the both ages of wild-type mice. These results suggest that the invariant Vδ1⁺ T cells are crucial not only for optimal γδ T cell expansion but also for affecting the migration or microenvironment for other γδ T cells in the lung epithelium.     

One step engineering of T7-expression strains for protein production: increasing the host-range of the T7-expression system

The T7-expression system has been very useful for protein expression in Escherichia coli. However, it is often desirable to over-express proteins in species other than E. coli. Here, we constructed an inducible broad-host-range T7-expression transposon, which allows simple one-step construction of T7-expression strains in various species, providing the option to over-express proteins of interest in a broader host-range. This transposon contains the T7 RNA polymerase driven by the lacUV5 promoter, which is repressed by the lac-repressor. Leaky expression is prevented by the presence of T7-lysozyme on this construct. The complete T7-expression system is flanked by mariner transposon repeats of the suicidal R6Kgammaori plasmid, pBT20-Deltabla. Stable integration of the whole system is possible by a one-step selection for a Flp-excisable Gm(R)-marker. We showed the engineering of E. coli, Pseudomonas aeruginosa, Erwinia carotovora, Salmonella choleraesuis, Agrobacterium tumefaciens, and Chromobacterium violaceum strains with this construct and demonstrated the expression of the Burkholderia pseudomallei Asd protein in these hosts, by induction with isopropyl-beta-d-thiogalactopyranoside (IPTG).     

Inflammasomes in T cells

The concept of non-self recognition through germ-line encoded pattern recognition receptors (PRRs) has been well-established for professional innate immune cells. However, there is growing evidence that also T cells employ PRRs and associated effector functions in response to certain non-self or damage signals. Inflammasomes constitute a special subgroup of PRRs that is hardwired to a signaling cascade that culminates in the activation of caspase-1. Active caspase-1 processes pro-inflammatory cytokines of the IL-1 family and also triggers a lytic programmed cell death pathway known as pyroptosis. An increasing body of literature suggests that inflammasomes are also functional in T cells. On the one hand, conventional inflammasome signaling cascades have been described that operate similarly to pathways characterized in innate immune cells. On the other hand, unconventional functions have been suggested, in which certain inflammasome components play a role in unrelated processes, such as cell fate decisions and functions of T helper cells. In this review, we discuss our current knowledge on inflammasome functions in T cells and the biological implications of these findings for health and disease.     

Dynamics of T cell activation threshold tuning

T lymphocytes are believed to alter their sensitivity to TCR stimulation by means of a tunable cellular activation threshold. We present two modelling examples which show that the concept of a tunable threshold can be made mechanistically plausible. The tunable threshold is treated as an emergent property of the dynamics of the T cell's signalling machinery. In addition, we discuss how the dynamic properties of activation threshold tuning can be determined experimentally with the aid of these two models. We propose a novel 'avidity selection' mechanism for the initial stages of the immune response, based on the properties of the T cell activation threshold tuning mechanism we propose for the commitment to differentiation. Our main finding is that activation threshold tuning allows T cells to respond to relevant ligands with a detection threshold that is (i) uniform across both the T cell repertoire and the secondary lymphoid tissues, while (ii) retaining tolerance to autostimulation. Our analysis indicates that central tolerance enhances the efficiency of peripheral tolerance, casting new light on the role of negative selection in the thymus.     

用实时荧光PCR方法鉴定转基因玉米T14/T25

本研究以实时荧光PCR技术鉴定商业化种植的转基因玉米T14/T25品系。根据转基因玉米T14/T25转入的外源基因质粒图谱,设计转基因引物和探针进行PCR和实时荧光PCR检测,建立了转基因玉米品系鉴定的实时荧光PCR方法。实验结果表明,用TaqMan探针可检测到T14/T25产生的荧光信号,而对其他玉米品系则检测不到荧光信号,为转基因产品的鉴定检测提供了新方法。Abstract: To identify genetically modified (GM) maize T14/T25 lines, a real-time fluorescent PCR (RTF PCR) assay was performed in this study. Primers and Taqman probes specific for inserted genes in the T14/T25 were used to conduct the real-time fluorenscent (RTF) PCR and PCR assays. The RTF PCR method was established to detect and identify GM maize lines. The results show that the TaqMan probe could identify T14/T25 maize used, while other GM and NO-GM maize didn’t be detected. The RTF PCR could be a new method for detecting other genetically modified organism.     

Engineered T cells for cancer treatment

Adoptively transferred T cells have the capacity to traffic to distant tumor sites, infiltrate fibrotic tissue and kill antigen-expressing tumor cells. Various groups have investigated different genetic engineering strategies designed to enhance tumor specificity, increase T cell potency, improve proliferation, persistence or migratory capacity and increase safety. This review focuses on recent developments in T cell engineering, discusses the clinical application of these engineered cell products and outlines future prospects for this therapeutic modality.     

The balancing act of AKT in T cells

The serine/threonine-specific protein kinase AKT is gaining recognition as a major crossroad in numerous cellular signaling pathways through its ability to regulate cell differentiation, proliferation, survival and metabolism. This review focuses on the recent advances in AKT signaling and downstream events in T cells, emphasizing its contrasting role in conventional and regulatory (Treg) Tcell populations. Activation of AKT has been known for many years to be critical in the development and function of conventional Tcells. However, it has just recently been uncovered that AKTexerts an inhibitory effect on Treg generation and suppressor function. These studies have placed AKTat the nexus of Treg development and function, thus opening novel avenues for therapeutic manipulation.     

乳酸菌素Gassericin T基因的合成及其在大肠杆菌中的融合表达

目的:在大肠杆菌系统中表达有抗菌活性的乳酸菌素Gassericin T。方法:根据乳酸菌素Gassericin T的基因序列,把Gassericin T的结构基因gatA编码的氨基酸的密码子转换成大肠杆菌偏爱的形式;用人工合成的寡核苷酸片段,通过重叠PCR法扩增得到gatA片段(gat基因);将合成的gat基因插入pGEX-4T-1,构建pGEX-4T-1-gat融合表达载体,转化大肠杆菌DH5α株,IPTG诱导表达,经超声裂解后获得包涵体蛋白,经溶解、变性、复性处理后获得GST-Gassericin T融合蛋白;用琼脂扩散法测定其对金黄色葡萄球菌、大肠杆菌、李斯特菌、枯草杆菌等的抗菌活性。结果与结论:采用pGEX-4T-1融合表达系统在大肠杆菌中表达了有活性的Gassericin T,融合蛋白以包涵体形式存在。复性的融合蛋白对金黄色葡萄球菌和大肠杆菌有明显的抑制作用,对李斯特菌的抑制作用不明显。     

Induction of antitumor L3T4-positive T cells by OK-432 at tumor sites in mice

We have previously reported the development of antitumor effector cells by day 12 after tumor implantation using a murine malignant ascites model with BAMC-1 tumor, which could be cured completely by five consecutive i.p. injections of OK-432 starting on day 2. In contrast, the OK-432 treatment with the same protocol failed to cure the tumor-bearing athymic mice, though it could suppress tumor growth temporarily. The results suggest that T cells may play a critical role in achieving a therapeutic effect. The present study was designed to clarify the nature of the antitumor effector cells induced by OK-432 in euthymic mice. The number of tumor cells in the pertioneal cavity of OK-432-treated euthymic mice increased gradually up to day 12 and dropped suddenly on day 14, while in the athymic mice the tumor cells transiently decreased in the first 7 days then started to expand drastically on day 8. The timing of the appearance of the effector cells was examined by adoptive-transfer experiments. The peritoneal exudate cells (PEC) obtained from BAMC-1 bearing euthymic mice on various days during the treatments with OK-432 were passively transferred intraperitoneally on the respective days (synchronous transfer) or on day 7 (convergent transfer) to BAMC-1-bearing athymic mice, which were treated similarly with OK-432. More than 85% of the recipient athymic mice survived when an adoptive transfer was made on and after day 7. These results indicated that the effector cells developed before day 8 in euthymic mice. The effector cells detectable on day 7 in the PEC represent plastic- or nylon-wool-column-nonadherent cells, which could cure the tumor-bearing athymic mice. Furthermore, the effector cells were destroyed when the nylon-wool-column-nonadherent cells were treated with an anti-L3T4 antibody and complement whereas the same treatment with anti-Lyt2 antibody had no effect. These L3T4⁺ cells did not possess asialo-GM1 antigen. Although the exact mechanism of action of the effector cells is yet to be clarified, the induction of human equivalents of this type of effector cell would be a good parameter indicative of clinical effects induced by OK-432 or other biological response modifiers in an individual cancer patient.     

The Agrobacterium tumefaciens T pilus composed of cyclic T pilin is highly resilient to extreme environments

Agrobacterium tumefaciens T pili are long semi-rigid, flexuous filaments of 10 nm diameter that are primarily composed of T pilin cyclized protein subunits. The cyclic character of T pilin apparently confers a high level of structural stability on the T pilus. Purified T pili subjected to extreme environmental conditions such as acid and alkali, including glycerol remained relatively unaffected morphologically. T pili lost their semi-rigidity when subjected to high temperatures and high pH, and dissociated into donut shaped subunits when exposed to Triton X-100. Sodium dodecyl sulfate increased the uptake of uranyl acetate exposing a 2 nm wide lumen running the length of the T pilus filament.     

哮喘患者外周血Treg和Th1/Th2的变化及其与哮喘病情的关系

目的：探讨哮喘患者外周血调节性T细胞（Treg）以及辅助性T细胞（Th1/Th2）的比例的变化,探讨其在哮喘的临床治疗中的作用。方法：80例哮喘患者（哮喘组）按临床表现分为急性发作期组（54例）和缓解期组（26例）,同时选择50例健康体检者。应用流式细胞仪检测上述各组外周血CD4＋CD25＋Foxp3＋Treg、CD4＋IFN-γ＋Th1和CD4＋IL-4＋Th2细胞水平,并进行统计学分析。结果：哮喘组CD4＋CD25＋Foxp3＋Treg水平亦明显低于正常对照组（P〈0.05。其中急性发作期组Treg水平明显低于缓解期组和正常对照组（P〈0.05）。而哮喘组Th1/Th2比值显著低于对照组（P〈0.05）,且在哮喘急性发作组中Th1/Th2比值显著低于缓解期组和正常对照组（P〈0.05）。结论：提示Treg和Th在哮喘的发生和发展中起着重要的作用。