葡萄球菌肠毒素A联合PML-RAR α多肽刺激特异性T细胞杀伤NB4细胞株的作用

Objective: To investigate the effects of staphylococcal enterotoxin A (SEA) on the cytotoxicity of T cells stimulated by PML-RARa peptide in vitro. Methods: Peripheral blood mononuclear cells (MNC) from healthy donor were obtained by density gradient cantrifugation on Ficoll-Hypaque, MNC were cultured with PML-RARa peptide and SEA for 20 days. After induction, the cytotoxicity of T cells induced against NB4 and K562 cell lines were examined by Cell Counting Kit-8 (CCK-8).The CD4 and CD8 surface markers on the harvested CD3+ T cells were detected by flow cytometry (FCM). Results: The cytotoxicity of T cells induced by PML-RARa peptide with SEA was higher than that of T cells induced only by PML-RARa peptide against NB4 cells. The FCM assay showed that the ratio of CD4+/CD8+ T cells were gradually decreased in both groups of PML-RARa peptide whether with SEA or not at the intervals of day 5,10 and 20 day after induction, but the most significantly decreased by PML-RARa peptide with SEA. Conclusion: The specific cytotoxicity of T cells induced by PML-RARa peptide against NB4 cells could be enhanced with superantigen SEA.     

Detection of heat shock proteins but not superantigen by isolated oral bacteria from patients with Behcet's disease

We isolated bacteria from periodontal sites and mixed saliva in eight patients with Behcet's disease and surveyed them to determine whether they produced heat shock proteins (HSPs) and superantigen. Cultivable bacterial compositions from periodontal sites and saliva were examined by anaerobic culture using blood agar plates. Gram-negative anaerobic rods such as Prevotella intermedia, Fusobacterium nucleatum, and Capnocytophaga species were predominant in the isolates from the subgingival plaque samples. The Streptococcus mitis group was the most common type isolated from the saliva samples. To detect the production of HSPs, Western blot analyses were performed using a polyclonal rabbit antibody to Escherichia coli DnaK and a monoclonal antibody to Helicobacter pylori Gro-EL. Sonic extracts of 27 of the strains (79.4%) reacted with the antibody against E. coli DnaK. Nine of these 34 strains (26.5%) were found to produce HSPs that reacted with antibody to H. pylori Gro-EL. A total of 54 isolates were examined for superantigen activity against human peripheral leukocytes. Twenty-five gram-negative clinical strains isolated from chronic periodontitis lesions and 20 ATCC strains of microorganisms were also examined. We could not detect any superantigen activity in 500x diluted supernatant of the strains isolated from the eight patients with Behcet's disease. The present study indicates that the anaerobic strains isolated from the oral cavity of these patients produce HSPs, the production being related to Bechet's disease.     

Comparison of peptide and superantigen-induced anergy in a peptide-specific polyclonal human T cell line

T cells recognizing tetanus toxin peptide ‘p2’ (sequence830–844) raised in HLA DR6 individuals preferentiallyexpress V_ß2 in the TCR. A p2-specific T cell line(60% V_ß2₊) was used to compare peptide and superantigen[toxic shock syndrome toxin-1 (TSST-1)]-induced clonal anergy.Many experiments consistently revealed that the degree of ‘tolerance’or ‘clonal anergy’ induced by peptide was greaterthan with the superantigen TSST-1. These results are of interestin a number of contexts. First they suggest that using superantigensor anti-V_ß to delete the majority population of Tcells may not be sufficient to diminish an autoimmune response.Secondly, the results indicate that induction of anergy of alarge proportion of peptide-specific T cells does not lead toa suppressive bystander effect on the remaining responsive Tcells. These results emphasize the need to define the dominantautoantigenic epitopes in human autoimmune diseases, since peptidebased therapy such as the use of peptide analogues to induceanergy or a change in cytokine profile, is possibly more effectivein controlling undesired immune responses than the use of non-antigen,TCR-directed approaches such as superantigens.     

Local immunoglobulin production in nasal polyposis is modulated by superantigens

Background Chronic rhinosinusitis (CRS) with nasal polyps (NP) represents a persistent inflammation often characterized by local hyper‐immunoglobulinaemia and the presence of specific IgE to Staphylococcus aureus enterotoxins (SAEs). We aimed to study the systemic and local production of Igs in relation to plasma cells, B cells and specific IgE to SAEs. Methods Concentrations of IgE, IgG, IgM, IgA, IgG subclasses and specific IgE to SAE were determined on tissue homogenates and serum from 15 CRS patients with NP, 15 CRS without NP and 10 control patients. Tissue cryo‐sections were stained for CD19, CD20 and CD138 to demonstrate B and plasma cells. Results IgA, IgG and IgE concentrations were significantly higher in tissue homogenates, but not in serum, of NP compared with CRS and control subjects. NP with specific IgE to SAEs had significantly higher concentrations of IgG and IgE, and also showed a significantly higher fraction of IgG4 (P=0.003) and a lower fraction of IgG2 (P=0.04) than those without specific IgE production. Furthermore, naïve CD19⁺ B cell and plasma cell counts (CD138⁺) were significantly higher in NP tissue compared with controls or CRS. Conclusions The difference in IgE, IgG and IgA expression between NP tissue and serum, supported by increased numbers of plasma cells, suggests a local production of these Igs in NP in response to a chronic microbial trigger. The local immune response to SAE is associated with a further increased production of IgE and IgG, and a shift in IgG subclasses.     

Progressive decrease in VH3 gene family expression in plasma cells of HIV-infected patients

We have analysed the expression of V_H gene families In totalperipheral plasma cells of µ and isotypes from a groupof HIV-infected patients. CD19^– and CD20^– cellswere separated from B lymphocytes, and anchored RT-PCR productswere hybridized with specific V_H gene family probes and witha consensus J_H region probe. The V_H/J_H hybridization Intensityratios were taken as a parameter to measure V_H expression. Invivo V_H3 gene family expression is reduced In plasma cells ofall HIV-infected patients compared with adult healthy donors.This decrease is maximal in patients with AIDS: >90%. Thisis true for both studied Isotypes. Conversely, the two othermain V_H gene families, V_H1 and V_H4, show no significant variationIn expression. We and others have previously shown that V_H3gene family expression is first expanded and then decreasedIn peripheral B lymphocytes of HIV-infected patients. The presentresults extend these observations and show that V_H3 gene familyexpression is also affected In plasma cells. The existence ofa B cell superantlgen In HIV Infection may explain these data.This pronounced reduction In Vh3 family expression may participateIn the Impaired humoral responses against bacterial agents foundIn HIV-infected patients.     

THE EFFECT OF SUPERANTIGEN STAPHYLOCOCCAL ENTEROTOXIN B AND D- GALACTOSAMINE ON BALB/C MOUSE HEPATOCYTES

ResumeObiectifL'etudedel'ef/etdesuperantigdned'entdrotoxineBdestaphylocoqueetdeD--galactosaminesurhdpatocytesdesourisBalb/c.cathodes2,6,12,24he"resaprdsincubationdanslacavitypdritondaledesuperantigened'entdrotoxineBdestaphylocoque(EBS),ondeD--galactosamine(D--GaiN),onlexdeux,iefoieetiesangdessourisBLAB/cscutprdlevds.LafaCondemourirdeshdpatocytesestdtudiceparlamorphologieetiesdosagesbiochimiques.Enmimetempsiescytokines(TNF,IFN--y)circulantesscutdetecttesetlamortalicsdessourisdans24heur…     

人转铁蛋白—葡萄球菌肠毒素B偶联蛋白的抗肿瘤活性

目的 研究人转铁蛋白（ＨｕＴｆ）与金黄色葡萄球菌肠毒素Ｂ（ＳＥＢ）偶联后,其Ｔｆ－ＳＥＢ偶合蛋白的抗肿瘤活性,探讨Ｔｆ作为载体用于肿瘤导向免疫治疗的可能性。方法 利用凋亡细胞指数检测和超抗原依赖的细胞介导的细胞毒（ＳＤＣＣ）效应,观察该偶合蛋白的超抗原活性和激活Ｔ细胞杀伤肿瘤细胞的作用。结果 Ｔｆ－ＳＥＢ偶合蛋白比单体ＳＥＢ能更有效地激活Ｔ细胞的杀伤肿瘤细胞活性,并对ＭＨＣ－Ⅱ类分子阴性的肿瘤瘤细     

Mouse Mammary Tumor Virus (MMTV) and MMTV-like Viruses: An In-depth Look at a Controversial Issue

Since its discovery as a milk factor, mouse mammary tumor virus (MMTV) has been shown to cause mammary carcinoma and lymphoma in mice. MMTV infection depends upon a viral superantigen (sag)-induced immune response and exploits the immune system to establish infection in mammary epithelial cells when they actively divide. Simultaneously, it avoids immune responses, causing tumors through insertional mutagenesis and clonal expansion. Early studies identified antigens and sequences belonging to a virus homologous to MMTV in human samples. Several pieces of evidence fulfill a criterion for a possible causal role for the MMTV-like virus in human breast cancer (BC), though the controversy about whether this virus was linked to BC has raged for over 40 years in the literature. In this review, the most important issues related to MMTV, from its discovery to the present days, are retraced to fully explore such a controversial issue. Furthermore, the hypothesis of an MMTV-like virus raised the question of a potential zoonotic mouse–man transmission. Several studies investigate the role of an MMTV-like virus in companion animals, suggesting their possible role as mediators. Finally, the possibility of an MMTV-like virus as a cause of human BC opens a new era for prevention and therapy.     

超抗原及其应用研究进展

超抗原是一种功能非常活跃的蛋白质分子,能够刺激大量的T、B淋巴细胞活化,增强T、B淋巴细胞参与的免疫反应,从而增强机体的免疫力,因此超抗原的应用受到越来越多的关注,超抗原的免疫佐剂作用、提升细胞数量、尤其是超抗原疫苗的应用和抗肿瘤研究.本文主要综述了超抗原在应用方面的研究进展.     

靶向性超抗原EGF-SEA融合基因的构建及表达

目的：构建金黄色葡萄球菌肠毒素A（SEA）和表皮生长因子（EGF）表达载体。方法：利用PCR及RT-PCR技术分别克隆出SEA基因及EGF基因片断,以经过改良优化的桥式PCR将2个基因融合,再转入表达载体pET-44,经诱导剂诱导后分泌SEA-EGF融合蛋白。结果：所得SEA、EGF基因测序结果示与GENEBANK中公布的标准序列一致,且成功融合SEA-EGF基因并成功导入表达载体。结论：该研究成功构建了SEA-EGF表达载体,为进一步研究SEA-EGF融合蛋白抗头颈肿瘤靶向免疫治疗奠定了基础。