PD-1/PD-L1信号通路在妊娠中的研究进展

<正>程序性细胞死亡受体1(Programmed cell death1,PD-1)及其配体(PD-L1和PD-L2)介导的信号通路在调控机体免疫稳态,尤其是T细胞免疫应答和T细胞免疫稳态中发挥重要作用。研究表明,PD-1/PD-L1信号通路除参与自身免疫、慢性感染性疾病、移植排斥和肿瘤免疫逃逸之外,还参与母胎免疫耐受的诱导和妊娠的维持[1]。效应T细胞(Th1/Th2/Th17)过度活化和/或介导免疫调节效应的调节性T     

阻断PD-1/PD-L1通路的免疫疗法在恶性肿瘤治疗中的研究进展

近年来,程序性死亡受体1(programmed death receptor 1, PD-1)/程序性死亡配体1(programmed death ligand 1,PD-L1)信号通路作为介导肿瘤免疫逃逸的重要途径而备受关注,抑制甚至阻断PD-1/PD-L1通路以增强T细胞毒性作用、提高机体免疫应答成为当下研究热点并取得了一系列突破性成果。目前,以PD-1/PD-L1抑制剂和CRISPR-Cas9技术靶向敲除PD-1/PD-L1基因为代表的免疫治疗策略已开始从实验室走向临床。与此同时,新的免疫治疗靶点的发现和治疗策略的组合将有助于更好地实现对PD-1/PD-L1信号通路的抑制作用,从而更有效地发挥此种免疫疗法在肿瘤治疗中的辅助作用。但目前阻断PD-1/PD-L1通路的免疫疗法仍存在适用人群有限、治疗效果相对欠佳等缺陷。此外,传统的肿瘤治疗评价标准对免疫疗法并不完全适用,新的标准亟待完善并规范化以用于临床疗效评价。本文将从PD-1/PD-L1信号通路出发,简明阐述其机制,并对当前研究成果进行全面介绍,同时聚焦国内外最新研究进展并对这一领域的发展趋势作出展望。     

抗PD-1及PD-L1在肿瘤治疗中的进展

正程序性死亡受体-1(PD-1)与其配体(PD-L1、PD-L2)对T淋巴细胞的抑制、"耗竭"以及诱导免疫耐受发挥着至关重要的作用。在肿瘤患者体内,PD-1/PD-L1的高表达能够增强肿瘤的转移能力、导致患者死亡率上升,抑制PD-1/PD-L1信号通路成为新近研究的热点。美国食品及药品管理局     

PD-1/PD-L信号通路研究进展

PD-1是近年新发现的一个负性共刺激信号分子,其配体为PD-L1和PD-L2,共属于CD28/B7家族。PD-1/PD-L通路削弱、限制和/或终止T细胞、B细胞和骨髓细胞的活化及外周炎症的效应器功能;二者相互作用导致T细胞增殖抑制和细胞因子IL-2I、L-10和IFN-γ的分泌下降,在移植免疫、自身免疫及肿瘤免疫等体系中发挥着重要作用。     

简述影响肿瘤PD-L1表达的各种因素

程序性细胞死亡配体1(PD-L1)及其受体PD-1属于CD28/B7协同刺激分子超家族成员,具有负性协同刺激信号的作用。PD-L1/PD-1通路传导抑制性信号,抑制淋巴结CD8+T细胞的杀伤功能,对人体免疫应答起到负调节作用,降低其对肿瘤的杀伤作用。近年来,已有多种PD-L1/PD-1单克隆抗体进入肿瘤免疫治疗的临床研究阶段。本文就细胞因子、癌基因、MicroRNAs三个方面简述了调控PD-L1表达的分子机制,以期对PDL1单克隆抗体的临床研究提供参考。     

PD-1/PD-L1抑制性通路在病毒性感染中的研究进展

杀伤性T细胞(CTL)是病毒感染过程中主要的效应细胞.在急性病毒性感染中,CTL细胞通过杀伤病毒感染的细胞,分泌抗病毒细胞因子从而有效清除病毒.而在慢性病毒感染过程中,病毒特异性CTL发生克隆耗竭,细胞数量少,细胞功能受损,分泌细胞因子能力下降.目前证明,CD28家族成员Programmed Death-1(PD-1)是一种重要的细胞表面分子,能够抑制CTL细胞功能,参与外周免疫耐受,维持T细胞克隆耗竭,保护机体不受免疫病理损伤.在慢性病毒性感染中,T细胞表面的PD-1与其受体PD-L1/2结合后,传递抑制性信号,下调外周T细胞功能.阻断PD-1通路,能够重建CD8+T细胞功能,抑制病毒复制,促进病毒清除.因此,通过干扰PD-1/PD-L1抑制途径进行免疫调节,可能是处理慢性病毒感染性疾病的一个新方法.     

PD-1／PD-L信号通路研究进展

PD-1是近年新发现的一个负性共刺激信号分子，其配体为PD-L1和PD-L2，共属于CD28／B7家族。PD-1／PD-L通路削弱、限制和／或终止T细胞、B细胞和骨髓细胞的活化及外周炎症的效应器功能；二者相互作用导致T细胞增殖抑制和细胞因子IL-2、IL-10和IFN-γ的分泌下降，在移植免疫、自身免疫及肿瘤免疫等体系中发挥着重要作用。     

PD-1及PD-L1与肿瘤适应性免疫抵抗的研究进展

程序性死亡蛋白-1(programmed death protein 1,PD-1)与其配体程序性死亡配体1(programmed cell death-ligand 1,PD-L1)属于CD28/B7家族,是近年研究比较透彻的免疫检查点分子。PD-1/PD-L1通过调节外周组织中免疫反应的持续性和效价避免组织损伤并维持对于自身抗原的耐受。肿瘤细胞主动性抑制T细胞的机制称为适应性免疫抵抗(adaptive immune resistance),即肿瘤抗原特异性T细胞企图攻击肿瘤,但肿瘤细胞发生反应性改变(诱导表达PD-L1)从而避免免疫攻击。适应性免疫抵抗过程中的关键分子即为PD-1/PD-L1。PD-1/PD-L1抗体治疗已在临床试验中显示出良好的疗效,使阻断适应性免疫抵抗有望成为重要的肿瘤免疫治疗手段。分析肿瘤活检样本的基线免疫信息能指导制定个体化的免疫治疗方案。本文就PD-1/PD-L1的生物学结构、适应性免疫抵抗机制及相关临床决策等进行综述。     

PD-1/PD-L在淋巴瘤中的研究进展

淋巴瘤是一组异质性的淋巴造血系统恶性肿瘤。程序性死亡受体1(programmed death-1,PD-1)及其配体(programmed death-ligand,PD-L)在T细胞介导的免疫应答过程中发挥重要作用。PD-1与PD-L1/PD-L2之间的相互作用可引起细胞凋亡以及T细胞耗竭,进而抑制抗肿瘤免疫应答。近年来研究发现以PD-1/PD-L1为靶点的免疫检查点抑制剂可有效地恢复T细胞功能,为肿瘤的治疗带来希望。该文就PD-1/PD-L在淋巴瘤中的免疫组化研究进展作一综述,以期为淋巴瘤的诊疗提供参考。     

抗PD-1及PD-L1在肿瘤治疗中的进展北大核心CSCD

程序性死亡受体-1（PD-1）与其配体（PD-L1、PD-L2）对T淋巴细胞的抑制、＂耗竭＂以及诱导免疫耐受发挥着至关重要的作用。在肿瘤患者体内,PD-1/PD-L1的高表达能够增强肿瘤的转移能力、导致患者死亡率上升,抑制PD-1/PD-L1信号通路成为新近研究的热点。     

先兆子痫患者HLA-DQA1、-DQB、-DPA1基因多态性

目的：探讨人类白细胞抗原HLA-DQA1、-DQB1、-DPA1基因多态性与先兆子痫发病的关系。方法：采用序列特异性引物技术（PCR-SSP） 对46例先兆子痫患者和105例正常孕妇及其新生儿进行HLA-DQ-DPA1等位基因分型。结果：所有标本共检出11种HLA-DQA1基因表型、16种HLA-DQB1基因表型、6种HLA-DPA1基因表型。先兆子痫患者HLA-DQB1＊0301基因频率高于正常孕妇，差异有显著性（Pc=0．032，RR=2．43，AR=0．30），其余各基因表型频率两组比较差异均无显著性。结论：HLA-DQB1＊0301基因可能是一种先兆子痫发病的易感基因。     

Comprehensive sequence analysis of HLA-DQA1 and -DQB1 alleles and characterization of DRB1-QAP-DQA1-DQB1 haplotypes

It is well known that both chain and β chain of HLA-DQ are highly polymorphic. However the polymorphisms outside the hypervariable region were not fully examined so far. To further clarify the polymorphisms in DQ genes, we determined the nucleotide sequences of full length cDNA, spanning from the leader sequence to the stop codon, from 15 DQA1 alleles and 15 DQB1 alleles. We identified several new DQ alleles which had identical exon 2 sequence and were different in other exons. On the basis of the sequence analyses, a comprehensive PCR-based oligotyping system for DQA1 gene was established. We then characterized DRB1-QAP(DQA1 promoter)-DQA1-DQB1 haplotypes of B-lymphoblastoid cell lines homozygous for HLA and healthy unrelated Japanese and Norwegian populations. It was revealed that DQA1 alleles, which were identical in exon 2 but different in other exons, showed close linkage disequilibrium with diferent characteristic DRB1, QAP and DQB1 alleles. These results suggest that DR-DQ haplotypes have been generated in the early stage of molecular evolution.     

HLA-DRB1, -DQA1, -DQB1, -DPA1 and -DPB1 genes in Japanese multiple sclerosis patients

Japanese MS patients and controls were examined for the distribution of HLA-DRB1, -DQA1, -DQB1, -DPA1 and -DPB1 alleles using in vitro amplification of genomic DNA and probing with sequence-specific oligonucleotides. No significant difference in frequency of the examined alleles was observed among the two groups. This is in contrast to Norwegian MS patients, where an association to a combination of certain DQA1 and DQB1 alleles has previously been demonstrated.     

HLA-DRB1, -DQA1, -DQB1 and DPB1 susceptibility alleles in Cameroonian type 1 diabetes patients and controls

It is known that certain combinations of alleles within the human leucocyte antigen (HLA) complex are associated with susceptibility or resistance to type 1 diabetes. Variable associations of DR and DQ with type 1 diabetes are documented in Caucasians but rarely in African populations; however, the role of HLA-DP genes in type 1 diabetes remains uncertain. In order to investigate the HLA class II associations with type 1 diabetes in Cameroonians, we used sequence-specific oligonucleotide probing (SSOP) to identify DRB1, DQA1, DQB1 and DPB1 alleles in 10 unrelated C-peptide negative patients with type 1 diabetes and 90 controls from a homogeneous population of rural Cameroon. We found a significantly higher frequency of the alleles DRB1*03 (χ² = 17.9; P = 0.001), DRB1*1301 (χ² = 37.4; P < 0.0001), DQA1*0301 (χ² = 18.5; P = 0.001) and DQB1*0201 (χ² = 37.4; P < 0.001) in diabetes patients compared to the control group. The most frequent alleles in the control population were DQA1*01, DQB1*0602 and DRB1*15. The DRB1*04 allele was not significantly associated with type I diabetes in our study population. We observed no significant difference between patients and controls in DPB1 allele frequency. In conclusion, the data in Cameroonian diabetes patients suggest the existence of HLA class II predisposing and specific protective markers, but do not support previous reports of a primary association between HLA-DP polymorphism and development of type I diabetes .     

The Rad9-Hus1-Rad1 (9-1-1) clamp activates checkpoint signaling via TopBP1

DNA replication stress triggers the activation of Checkpoint Kinase 1 (Chk1) in a pathway that requires the independent chromatin loading of the ATRIP-ATR (ATR-interacting protein/ATM [ataxia-telangiectasia mutated]-Rad3-related kinase) complex and the Rad9-Hus1-Rad1 (9-1-1) clamp. We show that Rad9's role in Chk1 activation is to bind TopBP1, which stimulates ATR-mediated Chk1 phosphorylation via TopBP1's activation domain (AD), a domain that binds and activates ATR. Notably, fusion of the AD to proliferating cell nuclear antigen (PCNA) or histone H2B bypasses the requirement for the 9-1-1 clamp, indicating that the 9-1-1 clamp's primary role in activating Chk1 is to localize the AD to a stalled replication fork.