1,721,091 research outputs found
Interleukin 10 in Antiviral Responses
No full textThe type of immune response a host can raise against an invading parasite may often be decisive between chronicity or clearance, and in the worst cases between host survival and death. Helper T cells are key to determining whether antibody-mediated, inflammatory or cytolytic responses will be predominant. Interleukin 10 (IL10) is widely recognized to be the most important cytokine for anti-inflammatory reactions and tends to be associated to chronicity in quite a few types of viral infections. On the other hand, it has also been associated to tissue preservation in chronic viral disease. This review summarizes the most recent data available in the literature on this pivotal cytokine during experimental viral infection and in the clinical setting
Intracellular staining and detection of cytokines by fluorescence-activated flow cytometry
No full textThe detection of cytokines inside cells producing them has made a tremendous impact on the way immune reactivity is measured. Intracellular cytokine staining is the only immunological technique allowing determination of antigen-specific T cell function and phenotype at the same time; for this reason, it is one of the most popular methods to measure antigenicity in the evaluation of vaccine efficacy and in the study of infectious diseases. It is a flow cytometric technique based on staining of intracellular cytokines and cell markers (surface or cytoplasmic) with fluorescent antibodies after short term culture of stimulated immune cells in the presence of a protein secretion inhibitor, followed by fixation and permeabilization. Most experiments involve detection of five to ten different colors but many more can be detected by modern flow cytometers. Here, we discuss our experience using a standard protocol for intracellular cytokine staining
NO RECOGNITION OF MHC CLASS II+ CELLS INFECTED WITH A VACCINIA VIRUS ENCODING INFLUENZA TYPE-A NUCLEOPROTEIN BY CLASS II-RESTRICTED T-CELLS
No full textMHC class II is mostly charged by antigens derived from the outside of the antigen-presenting cell (APC), while class I presents endogenous antigens transported as peptides to the endoplasmic reticulum (ER) by specific transporters. Nevertheless, many antigens, especially glycoproteins, can be presented in vitro by class II even if endogenous. In order to investigate the class-II-restricted T-cell response to endogenously synthesized influenza nucleoprotein (NP) synthesized in infected cells as a model of non-glycosylated nuclear protein, class-II-restricted cytolytic T-cell (CTL) clones were established from BALB/c (H-2d) mice immunized with either influenza A/PR/8/34 (PR8) strain or with a vaccinia virus encoding the NP protein. Two of the clones were characterized in detail and turned out to be cytolytic, I-A(d)-restricted and NP peptide 218-229 specific. Even though an in vivo class-II-restricted T-cell response was elicited in BALB/c mice immunized with a vaccinia virus encoding nucleoprotein (Vacc-NP), class II+ mouse lymphoma cells were not lysed by the class-II-restricted clones in vitro when they were infected with the same virus or with a vaccinia virus encoding a truncated form of NP with no karyophilic sequence, showing that the de novo synthesized protein targeted to the nucleus or remaining in the cytoplasm cannot charge class II through the same pathway as class I in murine APC. These results extend previous observations made on transfected cells to cells that express an antigen during viral infection
Intracellular cytokine detection by fluorescence-activated flow cytometry: Basic principles and recent advances
No full textIntracellular cytokine staining is a flow cytometric technique consisting of culturing stimulated cytokine-producing cells in the presence of a protein secretion inhibitor, followed by fixation, permeabilization and staining of intracellular cytokines and cell markers (surface or cytoplasmic) with fluorescent antibodies. Up to 18 different colors can be detected by modern flow cytometers, making it the only immunological technique allowing simultaneous determination of antigen-specific T cell function and phenotype. In addition, cell proliferation and viability can be also measured. For this reason, it is probably the most popular method to measure antigenicity during vaccine trials and in the study of infectious diseases, along with ELISPOT. In this review, we will summarize its features, provide the protocol used by most laboratories and review its most recent applications
Influence of Dendritic Cells on Viral Pathogenicity
No full textAlthough most viral infections cause minor, if any, symptoms, a certain number result in serious illness. Viral disease symptoms result both from direct viral replication within host cells and from indirect immunopathological consequences. Dendritic cells (DCs) are key determinants of viral disease outcome; they activate immune responses during viral infection and direct T cells toward distinct T helper type responses. Certain viruses are able to skew cytokine secretion by DCs inducing and/or downregulating the immune system with the aim of facilitating and prolonging release of progeny. Thus, the interaction of DCs with viruses most often results in the absence of disease or complete recovery when natural functions of DCs prevail, but may lead to chronic illness or death when these functions are outmanoeuvred by viruses in the exploitation of DCs
Varicella-zoster virus infection: natural history, clinical manifestations, immunity and current and future vaccination strategies
Full text linkVaricella-zoster virus (VZV) is the etiologic agent of varicella (chicken pox), a childhood exanthematic disease that develops as a result of primary infection, and zoster (shingles), caused by reactivation of the virus persisting in a latent form in the dorsal sensory ganglia. Although varicella is generally a mild self-limiting illness, in immunocompromised subjects and adults it can have a serious clinical course that can lead to permanent damage of the central nervous system. In these and in most zoster cases, treatment with anti-herpetic drugs and/or immunotherapy is necessary. Because it is highly contagious, varicella is one of the most common exanthematic diseases. It is preventable by vaccination with an attenuated vaccine administered around the first year of age, and with a boost vaccination in school age. This article briefly describes the natural history and pathophysiology of VZV infection and its current epidemiology and provides an overview of current and future vaccine options to protect against varicella and/or zoster
The role of cytokines in T help responses to viruses
No full textAlthough most viral infections cause minor, if any, symptoms, a certain number result in serious illness. Viral disease symptoms result both from direct viral replication within host cells and from indirect immunopathological consequences. Dendritic cells (DCs) are key determinants of viral disease outcome; they activate immune responses during viral infection and direct T cells toward distinct T helper type responses. Certain viruses are able to skew cytokine secretion by DCs inducing and/or downregulating the immune system with the aim of facilitating and prolonging release of progeny. Thus, the interaction of DCs with viruses most often results in the absence of disease or complete recovery when natural functions of DCs prevail, but may lead to chronic illness or death when these functions are outmanoeuvred by viruses in the exploitation of DCs
Virome and Inflammasomes, a Finely Tuned Balance with Important Consequences for the Host Health
No full textThe virome is a multifaceted network of viruses inhabiting humans in health and disease. The virome forms a conspicuous portion of the so-called microbiome. Massive amount of data recently emerging demonstrates that the microbiome, once generically referred to as human (or animal) flora, is not a static entity but closely reflects what we eat, how and where we live, what we do, and many other unexpected variables. Composition, location, and amount of the microbiome have a direct impact on innate and adaptive host immune defences. Indeed, the microbiome may activate inflammasomes, multiprotein complexes that assemble in most human cells and that are responsible for the downstream effects of sensing microorganisms. Depending on their interplay with microbes, inflammasomes instruct host defences to tolerate or forfeit a specific microorganism. Indeed, the microbiome not only colonizes the gut and facilitates food digestion and absorption, but also shapes human immune defences and contributes to inflammatory processes by quenching or increasing them. Viruses that make up the virome play their part in shaping the immune system. Anelloviruses, one of the recently discovered families that are part of the virome, form a large fraction of human virome. They are present in most, if not all, human beings, where they replicate persistently without causing apparent disease. This review illustrates the role of the virome in modulating inflammation in cancer and various degenerative diseases and provides strong evidence for Anelloviruses as useful and practical molecular markers to monitor inflammatory processes and immune system competence
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