CD4^+ T cell-mediated presentation of non-infectious HIV-1 virion antigens to HIV-specific CD8^+ T cells

Background The mechanism of chronic immune activation and impairment of HIV-specific immune responses during chronic infection is not fully understood. However, it is known that high immune activation leads to more rapid progression to AIDS. We hypothesize that CD4^＋ T cell-mediated viral antigen presentation contributes to this pathologic immune activation in HIV-infected individuals. Methods HIV-specific T cells, responding to noninfectious HIV-1 virions as antigen, were measured by flow cytometric assays. These experimental conditions reflect the in vivo condition where noninfectious HIV-1 represents more than 99% of the antigens. Results CD4^＋ T cells purified from HIV-infected individuals were capable of cross presenting exogenous noninfectious HIV-1 virions to HIV-1-specific CD8^＋ T cells. Cross presentation required the entry of HIV-1 to CD4^＋ T cells and antigen translocation from endoplasmic reticulum to the Golgi complex. Blocking CD4^＋ mediated activation of HIV-specific CD8^＋ T cells and redirecting the viral antigens to antigen presenting cells improved HIV-specific T cell responses. Contusions One possible cause of chronic immune activation and impairment of HIV-1 specific T cell responses is represented by HIV-1 harboring CD4^＋ T cells cross presenting HIV-1 antigen to activate CD8^＋ T cells. This new mechanism provides the first evidence that cross presentation of noninfectious HIV-1 virions play a role in the immunopathogenesis of HIV-1 infection.

系统性红斑狼疮患者外周血CD4^+和CD8^+细胞端粒长度及端粒酶活性的研究

目的:探讨系统性红斑狼疮(SLE)患者外周血CD 4+、CD 8+和CD 19+细胞端粒长度和端粒酶活性变化及其在发病中的作用。方法:用免疫磁珠法,从外周血单个核细胞分离CD 4+、CD 8+和CD 19+淋巴细胞,提取细胞蛋白后,用PCR为基础的端粒酶测定法(T e lom eric repeats am p lification protoco l,TRAP)测定端粒酶活性;Sou thernB lot测定细胞端粒长度。结果:SLE患者CD 4+、CD 8+和CD 19+细胞端粒酶活性均高于正常对照,但只有CD 19+细胞端粒酶活性与正常对照相比差异有显著性(P<0.05)。SLE患者CD 4+和CD 8+淋巴细胞的端粒长度均较正常对照明显缩短,CD 19+淋巴细胞的端粒长度无明显缩短。结论:SLE患者CD 19+细胞端粒酶活性显著增高,维持了细胞端粒长度;而CD 4+和CD 8+细胞端粒酶活性可能不足以维持由于细胞分裂所导致的细胞端粒缩短。

急性胰腺炎早期患者IL-6,TNF,CD_4^+/CD_8^+的变化及意义

目的揭示重型胰腺炎发病机制和早期监测指标。方法对 12例重型胰腺炎 (SAP) ,15例轻型胰腺炎 (MAP)病人和 13例正常人 (N )的外周血用ELISA法测定IL -6及TNF ;用间接免疫荧光法测定CD4 +、CD8+细胞。结果SAP组IL-6水平明显高于MAP组及N组 (P <0 .0 1) ,但MAP组与N组比较无差异 (P >0 .0 5 )。IL -6大于 10 0 pg/ml时预测SAP的敏感性为83 .33 % ,特异性 93 .33 % ;三组间TNF检出率无差异 ;CD4 +百分率在SAP组明显下降 (P <0 .0 1)。SAP组IL -6与CD4 +百分率呈明显负相关 (r =-0 .6 196 ,P <0 .0 5 )。结论SAP早期IL -6升高和细胞免疫功能抑制可能属其早期反应 ,测定IL -6有助于轻。

Changes of CD8+CD28-T regulatory cells in rat model of colitis induced by 2,4-dinitrofluorobenzene

AIM:To determine the changes of CD8+ T subsets especially CD8+CD28-T regulatory cells in rat model of experimental colitis induced by 2,4-dinitrofluorobenzene (DNFB). METHODS:The rat model of experimental colitis was induced by enema with DNFB.Ten days later,colonic intraepithelial and splenic lymphooltes were isolated from colitis animals (n=16) and controls (n=8).The proportion of CD8+ T cells,CD8+CD28+ T cells and CD8+CD28-T regulatory cells were determined by flow cytometry. RESULTS:The model of experimental colitis was successfully established by DNFB that was demonstrated by bloody diarrhea,weight loss and colonic histopathology.The proportion of CD8+ T cells in either splenic or colonic intraepithelial lymphocytes was not significantly different between colitis animals and controls (spleen:34.6±7.24 % vs 33.5±9.41%, colon:14.0±8.93 % vs 18.0±4.06 %,P>0.05).But CD8+CD28- T regulatory cells from colitis animals were significantly more than those from controls (spleen:11.3±2.26 % vs 5.64±1.01%, colon:6.50±5.37 % vs 1.07±0.65 %,P<0.05).In contrast, CD8+CD28+ T cells from colitis animals were less than those from controls (spleen:23.3±6.14 % vs 27.8±9.70 %,P=0.06; colon:7.52±4.18 % vs 16.9±4.07 %,P<0.05).The proportion of CD8+CD28-T regulatory cells in splenic and colon intraepithelial CD8+ T cells from colitis animals was higher than that from controls (spleen:33.3±5.49 % vs 18.4±7.26 %, colon:46.0±14.3 % vs6.10±3.72 %,P<0.005). CONCLUSION:Experimental colitis of rats can be induced by DNFB with simplicity and good reproducibility.The proportion of CD8+CD28-T regulatory cells in rats with experimental colitis is increased,which may be associated with the pathogenesis of colitis.

Host and viral factors contributing to CD8+ T cell failure in hepatitis C virus infection

Virus-specific CD8+ T cells are thought to be the major anti-viral effector cells in hepatitis C virus (HCV) infection. Indeed, viral clearance is associated with vigorous CD8+ T cell responses targeting multiple epitopes. In the chronic phase of infection, HCV-specific CD8+ T cell responses are usually weak, narrowly focused and display often functional defects regarding cytotoxicity, cytokine production, and proliferative capacity. In the last few years, different mechanisms which might contribute to the failure of HCV-specific CD8+ T cells in chronic infection have been identified, including insufficient CD4+ help, deficient CD8+ T cell differentiation, viral escape mutations, suppression by viral factors, inhibitory cytokines, inhibitory ligands, and regulatory T cells. In addition, host genetic factors such as the host’s human leukocyte antigen (HLA) background may play an important role in the efficiency of the HCV- specific CD8+ T cell response and thus outcome of infection. The growing understanding of the mechanisms contributing to T cell failure and persistence of HCV infection will contribute to the development of successful immunotherapeutical and -prophylactical strategies.

Key role of human leukocyte antigen in modulating human immunodeficiency virus progression: An overview of the possible applications

Host and viral factors deeply influence the human immunodeficiency virus(HIV) disease progression. Among them human leukocyte antigen(HLA) locus plays a key role at different levels. In fact, genes of the HLA locus have shown the peculiar capability to modulate both innate and adaptive immune responses. In particular, HLA class Ⅰmolecules are recognized by CD8+ T-cells and natural killers(NK) cells towards the interaction with T cell receptor(TCR) and Killer Immunoglobulin Receptor(KIR) 3DL1 respectively. Polymorphisms within the different HLA alleles generate structural changes in HLA classⅠpeptide-binding pockets. Amino acid changes in the peptide-binding pocket lead to the presentation of a different set of peptides to T and NK cells. This review summarizes the role of HLA in HIV progression toward acquired immunodeficiency disease syndrome and its receptors. Recently, many studies have been focused on determining the HLA binding-peptides. The novel use of immune-informatics tools, from the prediction of the HLA-bound peptides to the modification of the HLAreceptor complexes, is considered. A better knowledge of HLA peptide presentation and recognition are allowing new strategies for immune response manipulation to be applied against HIV virus.

Human mesenchymal stromal cells enhance the immunomodulatory function of CD8＋CD28- regulatory T cells

One important aspect of mesenchymal stromal cells （MSCs）-mediated immunomodulation is the recruitment and induction of regulatory T （Treg） cells. However, we do not yet know whether MSCs have similar effects on the other subsets of Treg cells. Herein, we studied the effects of MSCs on CD8＋CD28- Treg cells and found that the MSCs could not only increase the proportion of CD8＋CD28- T cells, but also enhance CD8＋CD28-T cells＇ ability of hampering naive CD4＋ T-cell proliferation and activation, decreasing the production of IFN-γ by activated CD4＋ T cells and inducing the apoptosis of activated CD4＋ T cells. Mechanistically, the MSCs affected the functions of the CD8＋CD28- T cells partially through moderate upregulating the expression of IL-10 and FasL. The MSCs had no distinct effect on the shift from CD8＋CD28＋ T cells to CD8＋CD28- T cells, but did increase the proportion of CD8＋CD28- T cells by reducing their rate of apoptosis. In summary, this study shows that MSCs can enhance the regulatory function of CD8＋CD28- Treg cells, shedding new light on MSCs-mediated immune regulation.

Novel SLA class I alleles of Chinese pig strains and their significance in xenotransplantation

To lay background for studying rejection mechanisms in xenotransplantation and developing the strategies for intervention, class I genes of swine leukocyte antigens (SLA) of three Chinese pig strains Bm, Gz and Yn were cloned and sequenced. The cDNA of the class I loci P1 and P14 were amplified by RT-PCR and subjected to insert into sequencing vectors. All six allelic sequences we examined, each two for one Chinese strain, are not identical to those reported, which allows these novel sequences receiving their accession numbers AY102467- AY102472 from GenBank. This study further reveals that the homologies of MHC class I genes in their primary structures and the deduced amino acids between Chinese pigs (SLA) and human (HLA-A*0201) are better than those between pigs and mice (H-2Db/H-2Kb). The comparison also indicates that the amino acid residues critical for recognition by human KIRs are altered in the swine class I molecules. The amino acids responsible for binding human CD8 coreceptor are largely conserved although there are two critical residues substituted. A functional test indicated that the human T cells specific for the prokaryotically expressed SLA Plprotein could respond quite well in vitro to the class I-positive swine chon-drocytes and PBMCs in presence of human APCs. This implies that, due to the substitution of two critical residues, the inaccessibility of human CD8 coreceptor to swine class I molecule might be contributable to the indirect pathway that the human T cells have to use for recognizing the SLA class I xenogeneic antigens.

Effects of“Moxibustion Serum”on Proliferation and Phenotypes of Tumor Infiltrating Lymphocytes

Tumor infiltrating lymphocytes (TIL) were cultured with “moxibustion serum”(MS), and the results were examined by flow cytometry. The results indicated that MS could enhance the proliferation of TIL,accelerate it to reach the exponential growth phase, and assist recombinant interleukin 2 (rIL-2) to enhance successively the percentage of CD3^+ positive cells, maintain the number of CD4^+ positive T cells, promote greatly the percentage of CD8^+ positive T cells among TILs, and reverse the CD4^+/CD8^+ ratio. Such cooperative effects rely on relative specificity of acupoints. It is suggested that MS is beneficial to the growth of TIL both in the aspects of proliferation and phenotypes.

乙型肝炎的T淋巴细胞亚群的演变规律

目的:了解不同类型乙型肝炎患者T淋巴细胞亚群的演变规律及意义。方法:我院2002年7月～2004年6月收治的16例急性肝炎、40例慢性肝炎及46例重型肝炎病例的抗凝血,通过流式细胞仪检测其T淋巴细胞亚群,对不同类型肝炎进行统计学分析。结果:慢性肝炎组与急性肝炎组比较CD3+,CD8+细胞计数降低且差异有显著性(P<0.05)。重型肝炎组与非重型肝炎组(急性肝炎组与慢性肝炎组)比较CD3+,CD4+,CD8+细胞计数明显降低(P<0.05),幼稚的CD4+,CD8+细胞计数明显升高(P<0.05)。结论:不同类型乙型肝炎的T淋巴细胞亚群有明显差异,乙型肝炎随着病情严重及病程延长,CD3+,CD4+,CD8+淋巴细胞逐渐减少,重型肝炎出现大量幼稚的CD4+CD8+淋巴细胞,T淋巴细胞亚群的变化可以反映病情严重程度及免疫状态,对免疫调节治疗有指导意义。

EFFECTS OF ACUPUNCTURE ON THE IMMUNOLOGICAL FUNCTIONS IN HEPATITIS B VIRUS CARRIERS

A contrast study on the effects of manual acupuncture and electroacupuncture wasconducted in 60 cases of chronic hepatitis B carriers.The results demonstrated that theimmunological functions,both cellular and humoral,were markedly regulated asevidenced by the negative turnover rates of HBsAg,HBeAg,anti-HBc and HBcAg,as wellas the positive turnover rate of anti-HBe.

Stress increases MHC-I expression in dopaminergic neurons and induces autoimmune activation in Parkinson’s disease

The expression of major histocompatibility complex class I(MHC-I),a key antigen-presenting protein,can be induced in dopaminergic neurons in the substantia nigra,thus indicating its possible involvement in the occurrence and development of Parkinson’s disease.However,it remains unclear whether oxidative stress induces Parkinson’s disease through the MHC-I pathway.In the present study,polymerase chain reaction and western blot assays were used to determine the expression of MHC-I in 1-methyl-4-phenylpyridinium(MPP+)-treated SH-SY5Y cells and a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)-induced Parkinson’s disease mouse model.The findings revealed that MHC-I was expressed in both models.To detect whether the expression of MHC-I was able to trigger the infiltration of cytotoxic T cells,immunofluorescence staining was used to detect cytotoxic cluster of differentiation 8(CD8)+T cell infiltration in the substantia nigra of MPTP-treated mice.The results indicated that the presentation of MHC-I in dopaminergic neurons was indeed accompanied by an increase in the number of CD8+T cells.Moreover,in MPTP-induced Parkinson’s disease model mice,the genetic knockdown of endogenous MHC-I,which was caused by injecting specific adenovirus into the substantia nigra,led to a significant reduction in CD8+T cell infiltration and alleviated dopaminergic neuronal death.To further investigate the molecular mechanisms of oxidative stress-induced MHC-I presentation,the expression of PTEN-induced kinase 1(PINK1)was silenced in MPP+-treated SH-SY5Y cells using specific small interfering RNA(siRNA),and there was more presentation of MHC-I in these cells compared with control siRNA-treated cells.Taken together,MPP+-/MPTP-induced oxidative stress can trigger MHC-I presentation and autoimmune activation,thus rendering dopaminergic neurons susceptible to immune cells and degeneration.This may be one of the mechanisms of oxidative stress-induced Parkinson’s disease,and implies the potential neuroprotective role of PINK1 in oxidative stress-induced MHC-I presentation.All animal experiments were approved by the Southern Medical University Ethics Committee(No.81802040,approved on February 25,2018).

Adenovirus induced acute hepatitis in non-human primates after liver-directed gene therapy

OBJECTIVE: To define the mechanism of acute hepatitis in non-human primates after liver directed gene therapy. METHODS: Differences in immune response exhibited by 8 rhesus monkeys receiving adenovirus (Ad) or lipofectamine-mediated gene transfer by various routes, the time course, and the nature of the specific immune responses to both adenoviral vectors and transgene products were studied using HE staining (H&E) and immunohistochemical staining. RESULTS: The monkeys developed mild to moderate acute hepatitis 1 to 3 weeks after intravenous or intrabiliary injection of first generation replication-defective adenoviruses carrying the Escherichia coli lacZ gene. This was accompanied by adenovirus-mediated T-cell proliferation and neutralizing antibodies to the adenovirus. Increased numbers of CD3(+), CD4(+) and CD8(+) T-lymphocytes were detected in the diseased livers, while B-lymphocytes were absent. Hepatocytes demonstrated increased expression of beta 2-microglobulins (beta 2-MG) and HLA-DR antigens in the plasma membranes. The development of acute hepatitis and the accompanying immune abnormalities were delayed in immunosuppressed monkeys until after the discontinuation of immunosuppressive therapy. The monkeys infused with Ad. CMVluc showed more significant and longer durations of hepatitis than the monkeys infused with adenoviruses carrying the lacZ gene. Lipofectamine-mediated gene transfer was inefficient. There was neither lacZ expression nor significant immune response in the liver of monkeys infused with lipofectamine via the portal vein or the common bile duct. CONCLUSION: Immune response to the hepatocytes in liver directed gene therapy is MHC class I restricted and T-cell mediated. Both adenoviral vectors and foreign genes are related to the liver damage. Mild to moderate hepatic inflammation seen with the E-1 deleted vector is reversible. Immunosuppression regimens may prolong transgene expression and delay the development of acute adenoviral hepatitis.

骨肉瘤特异性细胞毒T淋巴细胞的诱导及其抗肿瘤特性的研究

目的 诱导骨肉瘤特异性细胞毒T 淋巴细胞(osteosarco ma specific cytotoxic T ly mphocyte ,OSS- CTL) ,观察其体内外的抗肿瘤特性。方法 通过生化方法从HOS- 8603 细胞系中提取纯化骨肉瘤相关抗原(osteosarcom a associated antigen , OSAA) ,并与低剂量IL- 2 、CD 3 单抗协同刺激骨肉瘤致敏的淋巴细胞诱导产生OSS- CTL。结果 OSS- CTL 表型特征为CD 3 + 87-6 % ±6-3 % , CD 4 + 21-7 % ±4-1 % ,CD 8 + 94-7 % ±5-3 % ,CD 11b +1-9 % ±0-7 % ,HLA+ 79-3 % ±8-7 % ,即以CD 8 + T 细胞为主的异质细胞群, 对OSAA 相关的自体骨肉瘤细胞和HOS- 8603 细胞显示高亲和杀伤活性。体内实验表明, OSS-CTL 明显抑制裸鼠皮下骨肉瘤的生长。结论 OSS- CTL

Classical and non-classical MHC I molecule manipulation by human cytomegalovirus： so many targets--but how many arrows in the quiver？

Major mechanisms for the recognition of pathogens by immune cells have evolved to employ classical and non-classical major histocompatibility complex class I （MHC I） molecules. Classical MHC I molecules present antigenic peptide ligands on infected cells to CD8＋ T cells, whereas a key function for non-classical MHC I molecules is to mediate inhibitory or activating stimuli in natural killer （NK） cells. The structural diversity of MHC I puts immense pressure on persisting viruses, including cytomegaloviruses. The very large coding capacity of the human cytomegalovirus allows it to express a whole arsenal of immunoevasive factors assigned to individual MHC class I targets. This review summarizes achievements from more than two decades of intense research on how human cytomegalovirus manipulates MHC I molecules and escapes elimination by the immune system.