共查询到20条相似文献，搜索用时 31 毫秒
1.
枸杞多糖的免疫调节作用 总被引：7，自引：0，他引：7
枸杞多糖(LBP)对机体的免疫系统有积极的调节作用。综述了LBP对体液免疫、细胞免疫、单核巨噬细胞、NK细胞、空斑形成细胞、树突状细胞、细胞因子、受体表达、红细胞免疫、信号传导、神经-内分泌-免疫网络等的影响。LBP对体液免疫、细胞免疫、红细胞免疫有促进作用,能促进单核巨噬细胞、NK细胞、空斑形成细胞、树突状细胞、细胞因子的功能发挥,在受体表达、信号传导、神经-内分泌-免疫网络中起着积极的作用。 相似文献
2.
McDonald D Wu L Bohks SM KewalRamani VN Unutmaz D Hope TJ 《Science (New York, N.Y.)》2003,300(5623):1295-1297
Monocyte-derived dendritic cells (MDDCs) can efficiently bind and transfer HIV infectivity without themselves becoming infected. Using live-cell microscopy, we found that HIV was recruited to sites of cell contact in MDDCs. Analysis of conjugates between MDDCs and T cells revealed that, in the absence of antigen-specific signaling, the HIV receptors CD4, CCR5, and CXCR4 on the T cell were recruited to the interface while the MDDCs concentrated HIV to the same region. We propose that contact between dendritic cells and T cells facilitates transmission of HIV by locally concentrating virus, receptor, and coreceptor during the formation of an infectious synapse. 相似文献
3.
Randolph DA Huang G Carruthers CJ Bromley LE Chaplin DD 《Science (New York, N.Y.)》1999,286(5447):2159-2162
Subsets of murine CD4+ T cells localize to different areas of the spleen after adoptive transfer. Na?ve and T helper 1 (TH1) cells, which express the chemokine receptor CCR7, are home to the periarteriolar lymphoid sheath, whereas activated TH2 cells, which lack CCR7, form rings at the periphery of the T cell zones near B cell follicles. Retroviral transduction of TH2 cells with CCR7 forces them to localize in a TH1-like pattern and inhibits their participation in B cell help in vivo but not in vitro. Thus, differential expression of chemokine receptors results in unique cellular migration patterns that are important for effective immune responses. 相似文献
4.
Huang CC Lam SN Acharya P Tang M Xiang SH Hussan SS Stanfield RL Robinson J Sodroski J Wilson IA Wyatt R Bewley CA Kwong PD 《Science (New York, N.Y.)》2007,317(5846):1930-1934
The CCR5 co-receptor binds to the HIV-1 gp120 envelope glycoprotein and facilitates HIV-1 entry into cells. Its N terminus is tyrosine-sulfated, as are many antibodies that react with the co-receptor binding site on gp120. We applied nuclear magnetic resonance and crystallographic techniques to analyze the structure of the CCR5 N terminus and that of the tyrosine-sulfated antibody 412d in complex with gp120 and CD4. The conformations of tyrosine-sulfated regions of CCR5 (alpha-helix) and 412d (extended loop) are surprisingly different. Nonetheless, a critical sulfotyrosine on CCR5 and on 412d induces similar structural rearrangements in gp120. These results now provide a framework for understanding HIV-1 interactions with the CCR5 N terminus during viral entry and define a conserved site on gp120, whose recognition of sulfotyrosine engenders posttranslational mimicry by the immune system. 相似文献
5.
Biragyn A Ruffini PA Leifer CA Klyushnenkova E Shakhov A Chertov O Shirakawa AK Farber JM Segal DM Oppenheim JJ Kwak LW 《Science (New York, N.Y.)》2002,298(5595):1025-1029
beta-Defensins are small antimicrobial peptides of the innate immune system produced in response to microbial infection of mucosal tissue and skin. We demonstrate that murine beta-defensin 2 (mDF2beta) acts directly on immature dendritic cells as an endogenous ligand for Toll-like receptor 4 (TLR-4), inducing up-regulation of costimulatory molecules and dendritic cell maturation. These events, in turn, trigger robust, type 1 polarized adaptive immune responses in vivo, suggesting that mDF2beta may play an important role in immunosurveillance against pathogens and, possibly, self antigens or tumor antigens. 相似文献
6.
Recognition of self antigens by skin-derived T cells with invariant gamma delta antigen receptors 总被引：12，自引：0，他引：12
Thy-1+ dendritic epidermal T cells (dECs) express invariant gamma delta antigen receptors and are found in intimate contact with keratinocytes in murine epidermis--thus raising the possibility that keratinocytes express a ligand for the antigen receptor of these T cells. Thy-1+ dECs were stimulated to produce lymphokines by interaction with keratinocytes in vitro. This stimulation was mediated through the dEC antigen receptor and did not appear to be restricted by the major histocompatibility complex. Thus, dECs can recognize self antigens and may participate in immune surveillance for cellular damage rather than for foreign antigens. 相似文献
7.
Peng G Guo Z Kiniwa Y Voo KS Peng W Fu T Wang DY Li Y Wang HY Wang RF 《Science (New York, N.Y.)》2005,309(5739):1380-1384
CD4+ regulatory T (Treg) cells have a profound ability to suppress host immune responses, yet little is understood about how these cells are regulated. We describe a mechanism linking Toll-like receptor (TLR) 8 signaling to the control of Treg cell function, in which synthetic and natural ligands for human TLR8 can reverse Treg cell function. This effect was independent of dendritic cells but required functional TLR8-MyD88-IRAK4 signaling in Treg cells. Adoptive transfer of TLR8 ligand-stimulated Treg cells into tumor-bearing mice enhanced anti-tumor immunity. These results suggest that TLR8 signaling could play a critical role in controlling immune responses to cancer and other diseases. 相似文献
8.
Lalani AS Masters J Zeng W Barrett J Pannu R Everett H Arendt CW McFadden G 《Science (New York, N.Y.)》1999,286(5446):1968-1971
Chemokine receptors serve as portals of entry for certain intracellular pathogens, most notably human immunodeficiency virus (HIV). Myxoma virus is a member of the poxvirus family that induces a lethal systemic disease in rabbits, but no poxvirus receptor has ever been defined. Rodent fibroblasts (3T3) that cannot be infected with myxoma virus could be made fully permissive for myxoma virus infection by expression of any one of several human chemokine receptors, including CCR1, CCR5, and CXCR4. Conversely, infection of 3T3-CCR5 cells can be inhibited by RANTES, anti-CCR5 polyclonal antibody, or herbimycin A but not by monoclonal antibodies that block HIV-1 infection or by pertussis toxin. These findings suggest that poxviruses, like HIV, are able to use chemokine receptors to infect specific cell subtypes, notably migratory leukocytes, but that their mechanisms of receptor interactions are distinct. 相似文献
9.
Anderson AC Anderson DE Bregoli L Hastings WD Kassam N Lei C Chandwaskar R Karman J Su EW Hirashima M Bruce JN Kane LP Kuchroo VK Hafler DA 《Science (New York, N.Y.)》2007,318(5853):1141-1143
CD4+ T helper 1 (TH1) cells are important mediators of inflammation and are regulated by numerous pathways, including the negative immune receptor Tim-3. We found that Tim-3 is constitutively expressed on cells of the innate immune system in both mice and humans, and that it can synergize with Toll-like receptors. Moreover, an antibody agonist of Tim-3 acted as an adjuvant during induced immune responses, and Tim-3 ligation induced distinct signaling events in T cells and dendritic cells; the latter finding could explain the apparent divergent functions of Tim-3 in these cell types. Thus, by virtue of differential expression on innate versus adaptive immune cells, Tim-3 can either promote or terminate TH1 immunity and may be able to influence a range of inflammatory conditions. 相似文献
10.
Asagiri M Hirai T Kunigami T Kamano S Gober HJ Okamoto K Nishikawa K Latz E Golenbock DT Aoki K Ohya K Imai Y Morishita Y Miyazono K Kato S Saftig P Takayanagi H 《Science (New York, N.Y.)》2008,319(5863):624-627
Cathepsin K was originally identified as an osteoclast-specific lysosomal protease, the inhibitor of which has been considered might have therapeutic potential. We show that inhibition of cathepsin K could potently suppress autoimmune inflammation of the joints as well as osteoclastic bone resorption in autoimmune arthritis. Furthermore, cathepsin K-/- mice were resistant to experimental autoimmune encephalomyelitis. Pharmacological inhibition or targeted disruption of cathepsin K resulted in defective Toll-like receptor 9 signaling in dendritic cells in response to unmethylated CpG DNA, which in turn led to attenuated induction of T helper 17 cells, without affecting the antigen-presenting ability of dendritic cells. These results suggest that cathepsin K plays an important role in the immune system and may serve as a valid therapeutic target in autoimmune diseases. 相似文献
11.
Human gammadelta T cells are considered to play a vital role in protective immunity through cytokine secretion and cytotoxic activity. We report that cells expressing the Vgamma2Vdelta2+-T cell receptor (Vdelta2+ T cells) also display principal characteristics of professional antigen-presenting cells such as dendritic cells. Thus, when activated, these cells efficiently processed and displayed antigens and provided co-stimulatory signals sufficient for strong induction of na?ve alphabeta T cell proliferation and differentiation. We suggest that, upon microbial activation, Vdelta2+ T cells participate in the induction of adaptive immune responses and that these cells may be a useful tool in vaccine development and immunotherapy. 相似文献
12.
Heil F Hemmi H Hochrein H Ampenberger F Kirschning C Akira S Lipford G Wagner H Bauer S 《Science (New York, N.Y.)》2004,303(5663):1526-1529
Double-stranded ribonucleic acid (dsRNA) serves as a danger signal associated with viral infection and leads to stimulation of innate immune cells. In contrast, the immunostimulatory potential of single-stranded RNA (ssRNA) is poorly understood and innate immune receptors for ssRNA are unknown. We report that guanosine (G)- and uridine (U)-rich ssRNA oligonucleotides derived from human immunodeficiency virus-1 (HIV-1) stimulate dendritic cells (DC) and macrophages to secrete interferon-alpha and proinflammatory, as well as regulatory, cytokines. By using Toll-like receptor (TLR)-deficient mice and genetic complementation, we show that murine TLR7 and human TLR8 mediate species-specific recognition of GU-rich ssRNA. These data suggest that ssRNA represents a physiological ligand for TLR7 and TLR8. 相似文献
13.
Innate antiviral responses by means of TLR7-mediated recognition of single-stranded RNA 总被引：1，自引：0，他引：1
Diebold SS Kaisho T Hemmi H Akira S Reis e Sousa C 《Science (New York, N.Y.)》2004,303(5663):1529-1531
Interferons (IFNs) are critical for protection from viral infection, but the pathways linking virus recognition to IFN induction remain poorly understood. Plasmacytoid dendritic cells produce vast amounts of IFN-alpha in response to the wild-type influenza virus. Here, we show that this requires endosomal recognition of influenza genomic RNA and signaling by means of Toll-like receptor 7 (TLR7) and MyD88. Single-stranded RNA (ssRNA) molecules of nonviral origin also induce TLR7-dependent production of inflammatory cytokines. These results identify ssRNA as a ligand for TLR7 and suggest that cells of the innate immune system sense endosomal ssRNA to detect infection by RNA viruses. 相似文献
14.
Shen Y Zhou D Qiu L Lai X Simon M Shen L Kou Z Wang Q Jiang L Estep J Hunt R Clagett M Sehgal PK Li Y Zeng X Morita CT Brenner MB Letvin NL Chen ZW 《Science (New York, N.Y.)》2002,295(5563):2255-2258
To examine the role of T cell receptor (TCR) in gammadelta T cells in adaptive immunity, a macaque model was used to follow Vgamma2Vdelta2+ T cell responses to mycobacterial infections. These phosphoantigen-specific gammadelta T cells displayed major expansion during Mycobacterium bovis Bacille Calmette-Guérin (BCG) infection and a clear memory-type response after BCG reinfection. Primary and recall expansions of Vgamma2Vdelta2+ T cells were also seen during Mycobacterium tuberculosis infection of naive and BCG-vaccinated macaques, respectively. This capacity to rapidly expand coincided with a clearance of BCG bacteremia and immunity to fatal tuberculosis in BCG-vaccinated macaques. Thus, Vgamma2Vdelta2+ T cells may contribute to adaptive immunity to mycobacterial infections. 相似文献
15.
外泌体是一种细胞分泌的囊泡，里面含有丰富的核酸和蛋白质等物质，对于信息的传递、免疫功能的调节具有重要作用.本研究通过培养巨噬细胞、树突状细胞，收集上清液，分别采用外泌体提取试剂盒法和超速离心法提取外泌体，使用透射电镜法和Western blot法进行外泌体鉴定. 将提取的外泌体转染荧光标记，与淋巴细胞共同孵育24 h.采用含荧光标记的miR-155，分别转染到巨噬细胞和树突细胞中，提取细胞上清的外泌体，与淋巴细胞共孵育24 h.结果显示：超速离心法提取的外泌体更纯，但是SBI试剂盒提取的外泌体更多，适用于下一步试验；巨噬细胞及树突状细胞分泌的外泌体加荧光标记与淋巴细胞共培养后，可使淋巴细胞荧光增加；荧光标记miR-155的外泌体与淋巴细胞共培养，可使淋巴细胞荧光增加. 本研究证实了树突细胞、巨噬细胞分泌的外泌体及其包含的miR-155可作用于淋巴细胞，参与免疫细胞间的通讯，为进一步阐明外泌体的作用机制奠定了理论基础. 相似文献
16.
Mueller SN Hosiawa-Meagher KA Konieczny BT Sullivan BM Bachmann MF Locksley RM Ahmed R Matloubian M 《Science (New York, N.Y.)》2007,317(5838):670-674
The chemokines CCL21 and CXCL13 are immune factors that dictate homing and motility of lymphocytes and dendritic cells in lymphoid tissues. However, the means by which these chemokines are regulated and how they influence cell trafficking during immune responses remain unclear. We show that CCL21 and CXCL13 are transiently down-regulated within lymphoid tissues during immune responses by a mechanism controlled by the cytokine interferon-gamma. This modulation was found to alter the localization of lymphocytes and dendritic cells within responding lymphoid tissues. As a consequence, priming of T cell responses to a second distinct pathogen after chemokine modulation became impaired. We propose that this transient chemokine modulation may help orchestrate local cellularity, thus minimizing competition for space and resources in activated lymphoid tissues. 相似文献
17.
Munn DH Sharma MD Lee JR Jhaver KG Johnson TS Keskin DB Marshall B Chandler P Antonia SJ Burgess R Slingluff CL Mellor AL 《Science (New York, N.Y.)》2002,297(5588):1867-1870
Antigen-presenting cells (APCs) can induce tolerance or immunity. We describe a subset of human APCs that express indoleamine 2,3-dioxygenase (IDO) and inhibit T cell proliferation in vitro. IDO-positive APCs constituted a discrete subset identified by coexpression of the cell-surface markers CD123 and CCR6. In the dendritic cell (DC) lineage, IDO-mediated suppressor activity was present in fully mature as well as immature CD123+ DCs. IDO+ DCs could also be readily detected in vivo, which suggests that these cells may represent a regulatory subset of APCs in humans. 相似文献
18.
携Hsp70的PRRSV ORF5与ORF6基因重组质粒构建及在Cos-7细胞中的表达 总被引：1，自引：0，他引：1
为构建高效猪繁殖与呼吸综合征病毒(PRRS)DNA疫苗,利用Hsp70作为免疫佐剂增强免疫功能的特点,构建了含PRRSV ORF5,ORF6基因的融合表达载体pCI-ORF5-ORF6A,以及携带HSP70基因的融合表达载体pCI-ORF5-ORF6B-Hsp70,转染Cos-7细胞。IFA检测结果显示,两个融合表达载体均能在Cos-7细胞中表达;Western blot检测证实转染质粒pCI-ORF5-ORF6A和 pCI-ORF5-ORF6B-Hsp70在42.7 Ku,112.2 Ku分别表达出特异性条带。结果显示所构建的重组质粒能在Cos-7细胞内进行良好的表达,且表达的蛋白具有免疫原性。 相似文献
19.
Gonzalez E Kulkarni H Bolivar H Mangano A Sanchez R Catano G Nibbs RJ Freedman BI Quinones MP Bamshad MJ Murthy KK Rovin BH Bradley W Clark RA Anderson SA O'connell RJ Agan BK Ahuja SS Bologna R Sen L Dolan MJ Ahuja SK 《Science (New York, N.Y.)》2005,307(5714):1434-1440
Segmental duplications in the human genome are selectively enriched for genes involved in immunity, although the phenotypic consequences for host defense are unknown. We show that there are significant interindividual and interpopulation differences in the copy number of a segmental duplication encompassing the gene encoding CCL3L1 (MIP-1alphaP), a potent human immunodeficiency virus-1 (HIV-1)-suppressive chemokine and ligand for the HIV coreceptor CCR5. Possession of a CCL3L1 copy number lower than the population average is associated with markedly enhanced HIV/acquired immunodeficiency syndrome (AIDS) susceptibility. This susceptibility is even greater in individuals who also possess disease-accelerating CCR5 genotypes. This relationship between CCL3L1 dose and altered HIV/AIDS susceptibility points to a central role for CCL3L1 in HIV/AIDS pathogenesis and indicates that differences in the dose of immune response genes may constitute a genetic basis for variable responses to infectious diseases. 相似文献
20.
Plague bacteria target immune cells during infection 总被引：1，自引：0，他引：1
Marketon MM DePaolo RW DeBord KL Jabri B Schneewind O 《Science (New York, N.Y.)》2005,309(5741):1739-1741
The plague is caused by the bacterium Yersinia pestis. Plague bacteria are thought to inject effector Yop proteins into host cells via the type III pathway. The identity of the host cells targeted for injection during plague infection is unknown. We found, using Yop beta-lactamase hybrids and fluorescent staining of live cells from plague-infected animals, that Y. pestis selected immune cells for injection. In vivo, dendritic cells, macrophages, and neutrophils were injected most frequently, whereas B and T lymphocytes were rarely selected. Thus, it appears that Y. pestis disables these cell populations to annihilate host immune responses during plague. 相似文献