7 results
Search Results
2. Hepatitis B surface antigen could contribute to the immunopathogenesis of hepatitis B virus infection.
- Author
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Yasuteru Kondo, Masashi Ninomiya, Eiji Kakazu, Osamu Kimura, Tooru Shimosegawa, Kondo, Yasuteru, Ninomiya, Masashi, Kakazu, Eiji, Kimura, Osamu, and Shimosegawa, Tooru
- Subjects
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HEPATITIS B , *CELL surface antigens , *HEPATITIS B virus , *IMMUNE response , *IMMUNOSUPPRESSION , *T cells , *DENDRITIC cells , *VIRAL replication - Abstract
Various findings concerning the clinical significance of quantitative changes in hepatitis B surface antigen (HBsAg) during the acute and chronic phase of hepatitis B virus (HBV) infection have been reported. In addition to being a biomarker of HBV-replication activity, it has been reported that HBsAg could contribute to the immunopathogenesis of HBV persistent infection. Moreover, HBsAg could become an attractive target for immune therapy, since the cellular and humeral immune response against HBsAg might be able to control the HBV replication and life cycle. However, several reports have described the immune suppressive function of HBsAg. HBsAg might suppress monocytes, dendritic cells (DCs), natural killer (NK), and natural killer T (NK-T) cells by direct interaction. On the other hand, cytotoxic T lymphocytes (CTLs) and helper T (Th) cells were exhausted by high amounts of HBsAg. In this paper, we focused on the immunological aspects of HBsAg, since better understanding of the interaction between HBsAg and immune cells could contribute to the development of an immune therapy as well as a biomarker of the state of HBV persistent infection. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
3. Characteristics of Plasmacytoid Dendritic Cell and CD4+ T Cell in HIV Elite Controllers.
- Author
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Herbeuval, Jean-Philippe, Smith, Nikaïa, and Thèze, Jacques
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HIV-positive persons , *AIDS , *DENDRITIC cells , *CD4 antigen , *T cells , *IMMUNE response - Abstract
Despite variability, the majority of HIV-1-infected individuals progress to AIDS characterized by high viral load andmassive CD4+ T-cell depletion. However, there is a subset of HIV-1-positive individuals that does not progress and spontaneously maintains an undetectable viral load. This infrequent patient population is defined as HIV-1 controllers (HIV controllers), and represents less than 1% of HIV-1-infected patients. HIV-1-specific CD4+ T cells and the pool of central memory CD4+ T cells are also preserved despite immune activation due to HIV-1 infection. The majority of HIV controllers are also defined by the absence of massive CD4+ T-cell depletion, even after 10 years of infection. However, the mechanisms involved in protection against HIV-1 disease progression have not been elucidated yet. Controllers represent a heterogeneous population; we describe in this paper some common characteristics concerning innate immune response and CD4+ T cells of HIV controllers. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
4. Strategies for Enhancing Vaccine-Induced CTL Antitumor Immune Responses.
- Author
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Xin Yong, Yü-Feng Xiao, Gang Luo, Bin He, Mu-Han Lü, Chang-Jiang Hu, Hong Guo, and Shi-Ming Yang
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DENDRITIC cells , *IMMUNITY , *T cells , *TUMOR antigens , *TUMORS , *CANCER vaccines , *VACCINES ,TUMOR prevention - Abstract
Vaccine-induced cytotoxic T lymphocytes (CTLs) play a critical role in adaptive immunity against cancers. An important goal of current vaccine research is to induce durable and long-lasting functional CTLs that can mediate cytotoxic effects on tumor cells. To attain this goal, there are four distinct steps that must be achieved. To initiate a vaccine-induced CTL antitumor immune response, dendritic cells (DCs) must capture antigens derived from exogenous tumor vaccines in vivo or autologous DCs directly loaded in vitro with tumor antigens must be injected. Next, tumor-antigen-loaded DCs must activate CTLs in lymphoid organs. Subsequently, activated CTLs must enter the tumor microenvironment to perform their functions, at which point a variety of negative regulatory signals suppress the immune response. Finally, CTL-mediated cytotoxic effects must overcome the tolerance induced by tumor cells. Each step is a complex process that may be impeded in many ways. However, if these steps happen under appropriate regulation, the vaccine-induced CTL antitumor immune response will be more successful. For this reason, we should gain a better understanding of the basic mechanisms that govern the immune response. This paper, based on the steps necessary to induce an immune response, discusses current strategies for enhancing vaccine-induced CTL antitumor immune responses. [ABSTRACT FROM AUTHOR]
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- 2012
- Full Text
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5. Adaptive Immune Responses in Primary Cutaneous Sarcoidosis.
- Author
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Bordignon, Matteo, Rottoli, Paola, Agostini, Carlo, and Alaibac, Mauro
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SARCOIDOSIS , *EPITHELIAL cells , *T cells , *DENDRITIC cells , *IMMUNOREGULATION - Abstract
Sarcoidosis is a multisystemic inflammatory disorder with cutaneous lesions present in about one-quarter of the patients. Cutaneous lesions have been classified as specific and nonspecific, depending on the presence of nonnecrotizing epithelial cell granulomas on histologic studies. The development and progression of specific cutaneous sarcoidosis involves a complex interaction between cells of the adaptive immune systems, notably T-lymphocytes and dendritic cells. In this paper, we will discuss the role of T-cells and skin dendritic cells in the development of primary cutaneous sarcoidosis and comment on the potential antigenic stimuli that may account for the development of the immunological response.We will further explore the contributions of selected cytokines to the immunopathological process. The knowledge of the adaptive immunological mechanisms operative in cutaneous sarcoidosis may subsequently be useful for identifying prevention and treatment strategies of systemic sarcoidosis. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
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6. Tumor Antigen Cross-Presentation and the Dendritic Cell: Where it All Begins?
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M.McDonnell, Alison, Robinson, BruceW. S., and Currie, Andrew J.
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DENDRITIC cells , *ANTIGENS , *T cells , *TUMORS , *IMMUNE response - Abstract
Dendritic cells (DCs) are professional antigen-presenting cells (APCs) that are critical for the generation of effective cytotoxic T lymphocyte (CTL) responses; however, their function and phenotype are often defective or altered in tumor-bearing hosts, which may limit their capacity to mount an effective tumor-specific CTL response. In particular, the manner in which exogenous tumor antigens are acquired, processed, and cross-presented to CD8 T cells by DCs in tumor-bearing hosts is not well understood, but may have a profound effect on antitumor immunity. In this paper, we have examined the role of DCs in the cross-presentation of tumor antigen in terms of their subset, function, migration, and location with the intention of examining the early processes that contribute to the development of an ineffective anti-tumor immune response. [ABSTRACT FROM AUTHOR]
- Published
- 2010
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7. Regulation of Tumor Immunity by Tumor/Dendritic Cell Fusions.
- Author
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Homma, Sadamu, Takahara, Akitaka, Hara, Eiichi, Nagasaki, Eijiro, Komita, Hideo, Tajiri, Hisao, Gong, Jianlin, Ito, Masaki, Koido, Shigeo, Ohkusa, Toshifumi, and Namiki, Yoshihisa
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TUMORS , *IMMUNITY , *DENDRITIC cells , *IMMUNE response , *T cells , *ANTIGENS , *VACCINES - Abstract
The goal of cancer vaccines is to induce antitumor immunity that ultimately will reduce tumor burden in tumor environment. Several strategies involving dendritic cells- (DCs)- based vaccine incorporating different tumor-associated antigens to induce antitumor immune responses against tumors have been tested in clinical trials worldwide. Although DCs-based vaccine such as fusions of whole tumor cells and DCs has been proven to be clinically safe and is efficient to enhance antitumor immune responses for inducing effective immune response and for breaking T-cell tolerance to tumor-associated antigens (TAAs), only a limited success has occurred in clinical trials. This paper reviews tumor immune escape and current strategies employed in the field of tumor/DC fusions vaccine aimed at enhancing activation of TAAs-specific cytotoxic T cells in tumor microenvironment. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
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