去甲肾上腺素影响单核细胞抗原提呈的机制

１０＾－１３～１０＾－９ｍｏｌ／Ｌ的去甲肾上腺素体外作用时能促进人外周血单核细胞的抗原提呈功能（ＡＰＦ）。ＰＫＣ激活剂ＰＭＡ和抑制剂４ａ－ＰＤＤ分别能加强和抑制ＮＥ对Ｍｏｎ的ＡＰＦ的促进作用；异搏定能抑制ＮＥ的这种作用，而ＰＫＡ的抑制剂ＰＫＩ对ＮＥ的这种作用无。结果提示ＮＥ促进ＭｏｎＡＰＦ的机制可能涉及到Ｃａ＾２＋和ＰＫＣ，而与ＰＫＡ无关。     

BCG30主要分泌蛋白对尘螨变应性患者TH1/TH2平衡调节作用的观察

目的　研究结核杆菌相对分子质量 (Mr)为 30× 10 3的主要分泌蛋白 (BCG30 ,也称Ag85B)对尘螨变应原过敏所致的哮喘等变应性患者外周血单个核细胞 (PBMC)分泌TH1、TH2细胞因子的调控作用。方法　常规分离 2 7例尘螨过敏的变应性患者 (A) ,其中 18例哮喘患者 (A1)、9例变应性鼻炎或皮炎患者 (A2 )和 13例正常人 (B)的PBMC ,在离体与螨变应原、BCG30单独或复合共培养 ,ELISA法测定培养上清IL 5、IFN γ的水平。结果　A、A1、A2、B 4组无刺激状态下的IL 5、IFN γ水平无差异 (P >0 .0 5 )。尘螨变应原刺激可显著促进A、A1、A2 3组PBMC分泌IL 5 ,P均 <0 .0 5 ,同时 ,A组的IFN γ水平自身比较亦明显增高 (73.5 8pg ml± 30 .2 3pg mlvs 30 .71pg ml± 18.87pg ml,P <0 .0 5 )。将尘螨变应原与BCG30和PBMC进行复合培养 ,并与单独尘螨变应原刺激组比较 ,其IFN γ水平在A组 (92 .89pg ml± 2 9.0 7pg mlvs 73.5 8pg ml± 30 .2 3pg ml)和A1组 (87.6 0pg ml± 36 .4 5pg mlvs 5 8.75pg ml± 7.84pg ml)均较后者为高 (P均 <0 .0 5 ) ,且A组的IFN γ IL 5的比值较单独尘螨变应原刺激组显著增高 (5 .0 3± 1.36vs 4 .2 0± 1.6 4 ,P <0 .0 5 ) ,而A1组其比值亦有增高趋势 (P =0 .0 7)。正常人中各刺激组间所有指标均     

Interferon-gamma mediates antigen trafficking to MHC class II-positive late endosomes of enterocytes

MHC class II-positive late endosomes of enterocytes are thought to be involved in antigen presentation to CD4(+) T cells. In contrast to enterocytes of BALB/c mice, severe combined immunodeficiency (SCID) enterocytes lack MHC class II expression and fail to transport internalized ovalbumin (OVA) into late endosomes. IFN-gamma is known to induce MHC class II in enterocytes and antigen targeting to late endosomes in macrophages. In this study, we investigated the influence of IFN-gamma and MHC class II on the processes of antigen traffic in enterocytes. Subcellular targeting of OVA and MHC class II expression within enterocytes were examined in SCID, IFN-gamma-treated SCID, BALB/c and C57BL/6 MHC class II knockout (KO) mice after a single feed with OVA. Sorting of OVA into late endosomes was found in enterocytes from BALB/c, C57BL/6 KO and IFN-gamma-stimulated SCID mice, but not from untreated SCID mice. MHC class II expression was restricted to enterocytes of IFN-gamma-treated SCID and BALB/c mice, present at basolateral membranes and within endosomal compartments. These enterocytes further revealed colocalization of class II antigens and OVA in endosomes. We suggest that antigen trafficking into late endosomes of enterocytes is mediated by IFN-gamma and occurs in the absence of MHC class II.     

Dendritic cells in Leishmania major-immune mice harbor persistent parasites and mediate an antigen-specific T cell immune response

Upon infection with Leishmania major, a cause of human cutaneous leishmaniasis, mice of resistant strains are able to control the infection, with lesions resolving spontaneously. A long-lasting cell-mediated immunity protects them from reinfection. Nevertheless, small numbers of viable parasites persist in the lymph nodes of these mice. We have recently documented that, in addition to macrophages, epidermal Langerhans cells can ingest L. major. Furthermore, Langerhans cells have the unique ability to transport viable parasites from the infected skin to the draining lymph node for presentation to antigen-specific T cells and initiation of the cellular immune response. During migration, Langerhans cells develop into dendritic cells. In the present study, we analyzed whether dendritic cells support the persistence of parasites in immune hosts. Immunohistological studies and assays in vitro showed that in the lymph nodes of mice that have recovered from infection with L. major, both macrophages and dendritic cells harbor viable parasites. However, only dendritic cells were able to induce a vigorous T-cell immune response to L. major in vitro in the absence of exogenous antigen. Tracking experiments conducted in vivo suggested that the infected dendritic cells in the lymph nodes are derived from Langerhans cells that have emigrated from the skin. The data demonstrate that L. major-infected dendritic cells and macrophages in lymph nodes of immune animals represent long-term host cells, but only dendritic cells have the ability to present endogenous parasite antigen to T cells. Long-term infected dendritic cells may thus allow the sustained stimulation of a population of parasite-specific T cells, protecting the mice from reinfection. Our results favor the hypothesis that the persistence of antigen supports the maintenance of T cell memory and that dendritic cells are critically involved in this process.     

抗原特异性细胞毒性T细胞体外扩增方法的研究近展

抗原特异性细胞毒性T细胞(cytoxicTlymphocytes,CTLs)在细胞免疫应答中起着重要的效应功能,从而在抗肿瘤和抗感染免疫中发挥着重要作用。由于受到各种因素的限制和影响,抗原特异性CTLs无法在体内有效地诱导和扩增,因此,通过体外诱导和扩增CTLs后再将此CTLs回输到体内是一个比较理想的方法,且具有重要的应用价值,如何高效激活和扩增抗原特异性CTLs是此法能否成功应用的关键。     

检测白色念珠菌p47抗原ELISA法的建立及临床应用价值

目的 :建立检测血清中白色念珠菌相对分子质量 470 0 0 (p47)抗原的实验室方法 ,并探讨其临床应用价值。　方法 :亲和层析纯化白色念珠菌 p47抗原 ,制备抗 p47单抗和多抗 ,建立 EL ISA法检测血清中 p47抗原 ,并以美国 Biom erica公司试剂盒对照 ,同时检测血液病患者和念珠菌培养阳性的患者。　结果 :血液病组 6 9例患者中 ,本法检测 10例阳性 ,Biomerica法 9例阳性 ;培养阳性组 12 6例患者 ,本法检测 8例阳性 ,Biom erica法 6例阳性。两种方法的阳性符合率为 40 %。　结论 :对怀疑侵袭性念珠菌感染的患者 ,检测血清中 p47抗原是一种有应用前景的诊断方法。     

Contemplating immunopeptidomes to better predict them

The identification of T-cell epitopes is key for a complete molecular understanding of immune recognition mechanisms in infectious diseases, autoimmunity and cancer. T-cell epitopes further provide targets for personalized vaccines and T-cell therapy, with several therapeutic applications in cancer immunotherapy and elsewhere. T-cell epitopes consist of short peptides displayed on Major Histocompatibility Complex (MHC) molecules. The recent advances in mass spectrometry (MS) based technologies to profile the ensemble of peptides displayed on MHC molecules – the so-called immunopeptidome – had a major impact on our understanding of antigen presentation and MHC ligands. On the one hand, these techniques enabled researchers to directly identify hundreds of thousands of peptides presented on MHC molecules, including some that elicited T-cell recognition. On the other hand, the data collected in these experiments revealed fundamental properties of antigen presentation pathways and significantly improved our ability to predict naturally presented MHC ligands and T-cell epitopes across the wide spectrum of MHC alleles found in human and other organisms. Here we review recent computational developments to analyze experimentally determined immunopeptidomes and harness these data to improve our understanding of antigen presentation and MHC binding specificities, as well as our ability to predict MHC ligands. We further discuss the strengths and limitations of the latest approaches to move beyond predictions of antigen presentation and tackle the challenges of predicting TCR recognition and immunogenicity.     

Different cytokines regulate antigen uptake and presentation of a precursor dendritic cell line

Langerhans cells (LC) and dendritic cells (DC) need to be activated in order to perform their antigen-presenting function. In this study, we explored the influence of cytokines on the uptake and presentation of protein antigens by the retrovirally immortalized myeloid cell line FSDC. This cell line was generated from mouse fetal skin and was previously shown to have the characteristics of early DC precursors. Both FSDC and bone marrow-derived DC (BM-DC) were more effective in the pinocytosis of FITC-conjugated ovalbumin (FITC-OVA) and dextran (FITC-DX) than B cells or macrophages. Pretreatment of FSDC with granulocyte/macrophage colony-stimulating factor (GM-CSF) ± interleukin (IL)-4 enhanced the pinocytic uptake of FITC-OVA and FITC-DX, but did not induce antigen-presenting capacity. In contrast, untreated FSDC or FSDC pre-incubated with GM-CSF ± IL-4 suppressed T cell responses. Treatment of FSDC with IFN-γ reduced pinocytosis but increased the expression of MHC and co-stimulatory/adhesion molecules and promoted efficient presentation of OVA protein or peptide to the specific DO11.10 T cell hybridoma or to naive CD4⁺ T cells from DO11.10 TCR-transgenic mice. The results suggest that antigen uptake and antigen presentation in DC are regulated by different cytokine signals provided by the surrounding tissue.     

SARS荧光免疫诊断技术研究

目的应用基因工程技术,在昆虫细胞中表达SARS核蛋白基因,产生无感染性的核蛋白抗原,利用此蛋白制备抗原片,用于检测血清中SARS特异性抗体.方法从非典型性肺炎病人血清中提取病毒RNA,通过RT-PCR方法扩增出SARS核蛋白基因片段,将核蛋白基因插入杆状病毒,构建重组昆虫杆状病毒,转染昆虫细胞,收获细胞,经丙酮固定,制成SARS抗原片,建立了SARS荧光免疫方法(IFA).结果用此抗原片检测多份血清,仅与SARS病人血清起反应,而与正常人及其它发热病人血清不起反应.结论利用该方法制备抗原片,不需要P3实验室,操作简便,为诊断与研究SARS提供了方便而安全的方法.     

幽门螺杆菌感染患者血清尿素酶B亚单位测定及意义

目的探讨幽门螺杆菌(Helicobacter pylori,H.pylori)尿素酶B亚单位(Urease sulbunit B,UreB)核心多肽作为疫苗抗原的可能性.方法应用酶免疫法测定H.pylori感染患者血清游离Ure B及各型免疫复合物.结果61例H.pylori感染患者血清中,游离Ure B及Ure B-IgG、Ure B-IgA、Ure B-IgM任一项阳性者60例,占98.4%,其中游离Ure B阳性率63.9%,UreB-IgG为62.3%,Ure B-IgA为75.4%,UreR-IgM为78.7%.结论H.pylori感染患者血清中存在Ure B,Ure B核心多肽能引起特异性免疫应答,Ure B核心多肽可望成为疫苗抗原.