14 results
Search Results
2. Biophysiology of in ovo administered bioactive substances to improve gastrointestinal tract development, mucosal immunity, and microbiota in broiler chicks.
- Author
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Ayalew, Habtamu, Wang, Jing, Wu, Shugeng, Qiu, Kai, Tekeste, Ayalsew, Xu, Changchun, Lamesgen, Dessalegn, Cao, Sumei, Qi, Guanghai, and Zhang, Haijun
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CHICKS , *GASTROINTESTINAL system , *PHAGOCYTOSIS , *CELL receptors , *LYMPHOCYTE count , *T cells , *IMMUNITY , *PROBIOTICS - Abstract
Early embryonic exogenous feeding of bioactive substances is a topic of interest in poultry production, potentially improving gastrointestinal tract (GIT) development, stimulating immunization, and maximizing the protection capability of newly hatched chicks. However, the biophysiological actions and effects of in ovo administered bioactive substances are inconsistent or not fully understood. Thus, this paper summarizes the functional effects of bioactive substances and their interaction merits to augment GIT development, the immune system, and microbial homeostasis in newly hatched chicks. Prebiotics, probiotics, and synbiotics are potential bioactive substances that have been administered in embryonic eggs. Their biological effects are enhanced by a variety of mechanisms, including the production of antimicrobial peptides and antibiotic responses, regulation of T lymphocyte numbers and immune-related genes in either up- or downregulation fashion, and enhancement of macrophage phagocytic capacity. These actions occur directly through the interaction with immune cell receptors, stimulation of endocytosis, and phagocytosis. The underlying mechanisms of bioactive substance activity are multifaceted, enhancing GIT development, and improving both the innate and adaptive immune systems. Thus summarizing these modes of action of prebiotics, probiotics and synbiotics can result in more informed decisions and also provides baseline for further research. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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3. Dendritic cell-targeting polymer nanoparticle-based immunotherapy for cancer: A review.
- Author
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Hu, Yeye, Zhang, Wei, Chu, Xiaozhong, Wang, Aoran, He, Ziliang, Si, Chuan-Ling, and Hu, Weicheng
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DENDRITIC cells , *IMMUNOLOGICAL adjuvants , *NANOMEDICINE , *POLYMERS , *IMMUNE response , *IMMUNOTHERAPY , *T cells - Abstract
Created with BioRender.com [Display omitted] Cancer immunity is dependent on dynamic interactions between T cells and dendritic cells (DCs). Polymer-based nanoparticles target DC receptors to improve anticancer immune responses. In this paper, DC surface receptors and their specific coupling natural ligands and antibodies are reviewed and compared. Moreover, reaction mechanisms are described, and the synergistic effects of immune adjuvants are demonstrated. Also, extracellular-targeting antigen-delivery strategies and intracellular stimulus responses are reviewed to promote the rational design of polymer delivery systems. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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4. Intelligent photothermal dendritic cells restart the cancer immunity cycle through enhanced immunogenic cell death.
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Sun, Zhihong, Deng, Guanjun, Peng, Xinghua, Xu, Xiuli, Liu, Lanlan, Peng, Jiaofeng, Ma, Yifan, Zhang, Pengfei, Wen, Austin, Wang, Yifan, Yang, Zhaogang, Gong, Ping, Jiang, Wen, and Cai, Lintao
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DENDRITIC cells , *CELL death , *T cells , *CANCER cells , *IMMUNITY , *HEAT shock proteins , *IMMUNOLOGICAL tolerance - Abstract
Dendritic cells (DCs) play a pivotal role in initiating antigen-specific tumor immunity. However, the abnormal function of DCs owing to the immunosuppressive tumor microenvironment (TME) and the insufficient number of tumor infiltrating DCs could promote immune tolerance and tumor immune escape. Thus, there is great potential to employ DCs to induce efficient antitumor immunity. In this paper, we developed intelligent DCs (iDCs), which consist of nanoparticles loaded with photothermal agents (IR-797) and coated with a mature DC membrane. The DC cell membrane on the surface of iDCs preserves the ability to present antigens and prime T cells. The iDCs can also enter the lymph node and stimulate T cells. The activated T cells reduced the expression of heat shock proteins (HSPs) in tumor cells, rendering them more sensitive to heat stress. Subsequently, we used mild photothermal therapy (42–45 °C) to induce immunogenic cell death and contribute to a synergistic antitumor effect. iDCs as a refined and precise system in combination with DC-based immunotherapy and thermal therapy can be stored long-term and on a large scale, so they can be applied in many patients. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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5. A model on the influence of age on immunity to infection with Mycobacterium tuberculosis
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Friedman, Avner, Turner, Joanne, and Szomolay, Barbara
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IMMUNITY , *MYCOBACTERIUM tuberculosis , *T cells , *MATHEMATICAL models - Abstract
Abstract: Increasing susceptibility of the elderly to many infectious diseases is highly associated with the loss or delay in the generation of antigen-specific CD4+ T cells. For Mycobacterium tuberculosis infection, where antigen-specific CD4+ T cell derived IFN-γ is essential, such a loss can lead to a significant failure to control infection. The present paper develops a mathematical model of infection with M. tuberculosis in old mice. The model includes an early resistance to infection which is mediated by CD8+ T cells. A subsequent reversal of this phenotype results from the slow generation of CD4+ T cell mediated immunity in old age. The model simulations corroborate experimental data and hence, the model was used to test whether immunity to infection could be improved in old mice, if CD4+ T cell responses were enhanced. Our simulations indicate that boosting antigen presentation and T cell proliferation can decrease the M. tuberculosis burden in the lung. [Copyright &y& Elsevier]
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- 2008
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6. Virosome-mediated delivery of protein antigens in vivo: efficient induction of class I MHC-restricted cytotoxic T lymphocyte activity
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Bungener, Laura, Huckriede, Anke, de Mare, Arjan, de Vries-Idema, Jacqueline, Wilschut, Jan, and Daemen, Toos
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IMMUNITY , *T cells , *IMMUNOGLOBULINS , *GERM cells - Abstract
Abstract: Induction of CTL responses against protein antigens is an important aim in vaccine development. In this paper we present fusion-active virosomes as a vaccine delivery system capable of efficient induction of CTL responses in vivo. Virosomes are reconstituted viral membranes, which do not contain the genetic material of the virus they are derived from. Foreign macromolecules, including protein antigens, can be encapsulated in virosomes during the reconstitution process. Functionally reconstituted virosomes retain the cell binding and fusion characteristics of the native virus. Thus, upon uptake by cells through receptor-mediated endocytosis, virosomes will deliver their content to the cell cytosol. In a previous study, we demonstrated that protein antigens delivered in this manner to dendritic cells are efficiently processed for both MHC class I and class II presentation. Here, we studied in vivo induction of cellular immune responses against virosome-encapsulated ovalbumin (OVA) in mice. As little as 0.75μg OVA delivered by fusion-active virosomes was sufficient to induce a powerful class I MHC-restricted CTL response. All immunization routes that were used (i.m., i.p. and s.c.) resulted in efficient induction of CTL activity. The CTLs induced were cytotoxic in a standard 51Cr-release assay and produced IFNγ in response to OVA peptide. Thus, virosomes represent an ideal antigen delivery system for induction of cellular immunity against encapsulated protein antigens. [Copyright &y& Elsevier]
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- 2005
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7. Modelling the interaction of T-Cells, antigen presenting cells, and HIV-1 in vivo
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Lou, Jie and Shao, Yiming
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T cells , *LYMPHOCYTES , *ANTIGENS , *IMMUNITY , *BIOLOGY - Abstract
Abstract: We develop and analyze a model for the interactions of T-cells, antigen presenting cells (APCs), and HIV-1. Our model consists of five components: APCs, resting helper T-cells, activated uninfected helper T-cells, activated and infected helper T-cells, and the free virus. We emphasize the impact of APCs during HIV infection and the cell-to-cell contact manner in the transference of HIV-1 in vivo. The existence and stability of the uninfected steady state and those of the infected steady states are discussed. The uniform persistence of the system is also obtained. As a novel approach, multiple exposures of HIV-1 are illustrated and discussed in the paper. Through numerical stimulations, we check the sensitivity of APCs and helper T-cells in impacting the infection outcome and obtain some relevant results. We also give the lowest infectioe dose for certain individuals. [Copyright &y& Elsevier]
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- 2004
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8. Jump-starting the immune system: prime–boosting comes of age
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Woodland, David L.
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VACCINES , *IMMUNE response , *T cells , *IMMUNITY , *PATHOGENIC microorganisms , *ANIMAL models in research - Abstract
A major challenge for immunologists has been the development of vaccines designed to emphasize cellular immune responses. One particularly promising approach is the prime–boost strategy, which has been shown to generate high levels of T-cell memory in animal models. Recently, several papers have highlighted the power of prime–boost strategies in eliciting protective cellular immunity to a variety of pathogens and have demonstrated efficacy in humans. Coupled with recent advances in our understanding of the mechanisms underlying the generation, maintenance and recall of T-cell memory, the field is poised to make tremendous progress. This Review discusses the impact of these recent developments on the future of prime–boost vaccine strategies. [Copyright &y& Elsevier]
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- 2004
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9. ORIGINAL ARTICLE Novel Immunotherapies for Psoriasis: Clinical Research Delivers New Hope for Patients and Scientific Advances.
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Gottlieb, Alice B.
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PSORIASIS , *IMMUNITY , *IMMUNOTHERAPY , *IMMUNOLOGIC diseases , *T cells , *IMMUNE response - Abstract
Immunobiologics provide the hope for safe and effective long-term management of psoriasis, a life-disabling condition. The use of targeted immunotherapies as pathogenic probes has led to scientific discoveries that help uncover new information on the pathogenesis of psoriasis and on the control of cutaneous immunity. The research described in this paper employs targeted immunotherapies as pathogenic probes of T1-mediated immune disorders, using psoriasis as the primary disease model. This approach has wide applicability to other immune-mediated inflammatory isorders. [ABSTRACT FROM AUTHOR]
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- 2004
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10. Vaccinology for control of apicomplexan parasites: a simplified language of immune programming and its use in vaccine design
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Brake, David A.
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APICOMPLEXA , *IMMUNITY , *TOXOPLASMA , *T cells - Abstract
Most mammalian immune systems and parasites have co-evolved over the millennia, interacting within a common environment and communicating through a common language. This language is comprised of copious dialects in which a variety of host innate and acquired immune pathways actively interact with a multitude of parasite-specific survival strategies. Nonetheless, a simplified language is likely present since the same basic molecular and cellular mechanisms are associated with resistance or susceptibility to parasite infection. Protective immunity against protozoa within the phylum Apicomplexa (e.g. Cryptosporidia, Eimeria, Neospora, Plasmodia and Toxoplasma) is generally CD4+ T cell-dependent and elicited along the IL-12/IFN-γ/iNOS effector axis. This simplified language can be decoded in part by significant advances in understanding naı¨ve T cell activation, differentiation and generation of immunologic memory. Vaccine adjuvants and new immunisation strategies for generation of more potent immunity can also be viewed through this common language lens. The aim of this paper is to summarise recently published fundamental immunology studies, their relevance through examples in specific coccidian-host immune dialects, and how this simplified language can be used for the more rationale design of parasite vaccine control strategies. [Copyright &y& Elsevier]
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- 2002
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11. Stability of a general adaptive immunity HIV infection model with silent infected cell-to-cell spread.
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AlShamrani, N.H.
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CYTOTOXIC T cells , *HIV infections , *GLOBAL asymptotic stability , *T cells , *HIV infection transmission , *IMMUNITY , *DYNAMICAL systems - Abstract
This paper proposes and analyzes an adaptive immunity HIV infection model. The model describes the interaction between healthy CD 4 + T cells, silent (latent) infected cells, active infected cells, free HIV particles, Cytotoxic T lymphocytes (CTLs) and antibodies. The healthy CD 4 + T cells can be infected when they are contacted by one of the following: (i) free HIV particles, and this is known as virus-to-cell (VTC) transmission (ii) silent infected cells, and we call this mode of infection as silent HIV-infected cell-to-cell (CTC) transmission, and (iii) active infected cells, and we call this mechanism active HIV-infected CTC transmission. The incidence rates of the healthy CD 4 + T cells with free HIV particles, silent infected cells, and active infected cells are given by general functions. Moreover, the production/proliferation and removal/death rates of all compartments are represented by general functions. The model is an improvement of the existing HIV infection models which have neglected the incidence between the silent infected cells and healthy CD 4 + T cells. We first show that the model is well-posed. Then, we show that the model has five equilibria and their existence are governed by five threshold parameters. Under a set of conditions on the general functions and the threshold parameters, we have proven the global asymptotic stability of all equilibria by using Lyapunov's method. We have illustrated the theoretical results via numerical simulations. We have studied the effect of CTC transmission on the dynamical behavior of the system. We have shown that inclusion of CTC transmission decreases the concentration of the healthy CD4 + T cells and increases the concentrations of the infected cells and free HIV particles. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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12. Outside looking in: the inner workings of the crosspresentation pathway within dendritic cells
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Villadangos, Jose A., Heath, William R., and Carbone, Francis R.
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ANTIGENS , *IMMUNITY , *MAJOR histocompatibility complex , *IMMUNOGENETICS , *T cells - Abstract
The entry of exogenous antigen into the MHC class I-restricted crosspresentation pathway can contribute to CD8+ T cell tolerance and immunity, in particular to peripheral self-antigens or selected viruses and bacteria showing restricted tissue tropism. Dendritic cells are the key crosspresenting cells and, as such, they are thought to carry specialized machinery dedicated to this purpose. Two recent papers describe intracellular components tailored to the dendritic cell crosspresentation pathway. [Copyright &y& Elsevier]
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- 2007
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13. T helper cells, IL-2 and the generation of cytotoxic T-cell responses
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Malek, Thomas R.
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T cells , *LYMPHOCYTES , *IMMUNITY - Abstract
CD8 T-cell immunity is thought to require helper activity derived from CD4 T cells. Nevertheless, under some circumstances, effective CD8-dependent T-cell responses occur in vivo without CD4 T-cell help. Several recent papers help to explain this paradox and lead to a refined view concerning the role of T helper cells and interleukin-2 receptor signaling in the production of cytotoxic T lymphocytes. [ABSTRACT FROM AUTHOR]
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- 2002
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14. Will the idiotypic network help to solve natural tolerance?
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Coutinho, António
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IMMUNITY , *IMMUNOGLOBULIN idiotypes , *B cells , *T cells - Abstract
A recent paper on immunity and tolerance to antigenic determinants on antibody variable-regions (idiotypes) brings back to light the potential of idiotypic interactions among antibodies, B cells and T cells in the regulation of specific immune activities. The functional significance of idiotypic regulation has been established in a variety of systems, both concerning the establishment of ‘pre-immune’ diversity repertoires as well as the clonal regulation of immune responses to foreign and self-antigens. Also, recently the requirement for ‘dominant’ regulatory mechanisms in natural tolerance has received increasing support. It might thus be fruitful to evaluate the possibility that an idiotypic network has a fundamental role in the operation of the regulatory T cells that establish and maintain self-tolerance. [Copyright &y& Elsevier]
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- 2003
- Full Text
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