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"innate memory"

Thomas Crowley, Christopher D Buckley, Andrew R Clark
All organisms are constantly exposed to a variety of infectious and injurious stimuli. These induce inflammatory responses tailored to the threat posed. Whilst the innate immune system is the front line of response to each stimulant, it has been traditionally considered to lack memory, acting in a generic fashion until the adaptive immune arm can take over. This outmoded simplification of the roles of innate and acquired arms of the immune system has been challenged by evidence of myeloid cells altering their response to subsequent encounters based on earlier exposure...
May 5, 2018: Clinical and Experimental Immunology
Eva Kaufmann, Joaquin Sanz, Jonathan L Dunn, Nargis Khan, Laura E Mendonça, Alain Pacis, Fanny Tzelepis, Erwan Pernet, Anne Dumaine, Jean-Christophe Grenier, Florence Mailhot-Léonard, Eisha Ahmed, Jad Belle, Rickvinder Besla, Bruce Mazer, Irah L King, Anastasia Nijnik, Clinton S Robbins, Luis B Barreiro, Maziar Divangahi
The dogma that adaptive immunity is the only arm of the immune response with memory capacity has been recently challenged by several studies demonstrating evidence for memory-like innate immune training. However, the underlying mechanisms and location for generating such innate memory responses in vivo remain unknown. Here, we show that access of Bacillus Calmette-Guérin (BCG) to the bone marrow (BM) changes the transcriptional landscape of hematopoietic stem cells (HSCs) and multipotent progenitors (MPPs), leading to local cell expansion and enhanced myelopoiesis at the expense of lymphopoiesis...
January 11, 2018: Cell
José Alberto Choreño Parra, Nayeli Martínez Zúñiga, Luis Antonio Jiménez Zamudio, Luis Armando Jiménez Álvarez, Citlaltepetl Salinas Lara, Joaquín Zúñiga
Natural killer (NK) cells are lymphocytes of the innate immune system, which play an important role in the initial defense against a wide variety of pathogens, including viruses and intracellular bacteria. NK cells produce cytokines that enhance immune responses directed toward pathogens and also exert cytotoxic activity against infected cells, thereby eliminating the reservoir of infection. Their role in defense against Mycobacterium tuberculosis (Mtb) has been recently studied, and there is increasing evidence that highlight the importance of NK cell function during pulmonary tuberculosis (PTB), especially in the absence of optimal T-cell responses...
2017: Frontiers in Immunology
Paola Italiani, Diana Boraschi
Innate immune memory is the capacity of cells of the innate immune system, such as monocytes and macrophages, to react differently to an inflammatory or infectious challenge if previously exposed to the same or to another agent. Innate immune memory is a protective mechanism, based on epigenetic reprogramming, that ensures effective protection while limiting side effects of tissue damage, by controlling innate/inflammatory responses to repeated stimulations. Engineered nanoparticles (NPs) are novel challenges for our innate immune system, and their ability to induce inflammatory activation, thereby posing health risks, is currently being investigated with controversial results...
2017: Frontiers in Immunology
Mariusz P Madej, Elfi Töpfer, Diana Boraschi, Paola Italiani
Production and activity of interleukin (IL)-1β are kept under strict control in our body, because of its powerful inflammation-promoting capacity. Control of IL-1β production and activity allows IL-1 to exert its defensive activities without causing extensive tissue damage. Monocytes are the major producers of IL-1β during inflammation, but they are also able to produce significant amounts of IL-1 inhibitors such as IL-1Ra and the soluble form of the decoy receptor IL-1R2, in an auto-regulatory feedback loop...
2017: Frontiers in Pharmacology
Jason T White, Eric W Cross, Ross M Kedl
Memory-phenotype CD8+ T cells exist in substantial numbers within hosts that have not been exposed to either foreign antigen or overt lymphopenia. These antigen-inexperienced memory-phenotype T cells can be divided into two major subsets: 'innate memory' T cells and 'virtual memory' T cells. Although these two subsets are nearly indistinguishable by surface markers alone, notable developmental and functional differences exist between the two subsets, which suggests that they represent distinct populations. In this Opinion article, we review the available literature on each subset, highlighting the key differences between these populations...
June 2017: Nature Reviews. Immunology
Alice Barbarin, Emilie Cayssials, Florence Jacomet, Nicolas Gonzalo Nunez, Sara Basbous, Lucie Lefèvre, Myriam Abdallah, Nathalie Piccirilli, Benjamin Morin, Vincent Lavoue, Véronique Catros, Eliane Piaggio, André Herbelin, Jean-Marc Gombert
Unconventional T cells are defined by their capacity to respond to signals other than the well-known complex of peptides and major histocompatibility complex proteins. Among the burgeoning family of unconventional T cells, innate-like CD8(+) T cells in the mouse were discovered in the early 2000s. This subset of CD8(+) T cells bears a memory phenotype without having encountered a foreign antigen and can respond to innate-like IL-12 + IL-18 stimulation. Although the concept of innate memory CD8(+) T cells is now well established in mice, whether an equivalent memory NK-like T-cell population exists in humans remains under debate...
2017: Frontiers in Immunology
John J Seeley, Sankar Ghosh
LPS is a potent trigger of macrophage-mediated inflammation. However, prolonged exposure to LPS induces a state of tolerance that reprograms the inflammatory response, resulting in reduced inflammatory cytokine production in vitro and in vivo. Recent evidence suggests that LPS tolerance also increases the expression of a subset of genes that may protect animals from systemic infection while they are in the tolerized state. However, a molecular basis for these selective changes in inflammatory gene expression during LPS tolerance has remained elusive...
January 2017: Journal of Leukocyte Biology
Hitendra S Chand, Yohannes A Mebratu, Marena Montera, Yohannes Tesfaigzi
BACKGROUND: Airway epithelial cells (AECs) are crucial for mucosal and adaptive immunity but whether these cells respond in a memory-dependent manner is poorly studied. Previously, we have reported that LPS intratracheal instillation in rodents causes extensive neutrophilic inflammation and airway epithelial cell hyperplasia accompanied by mucous cell metaplasia (MCM). And the resolution process required a period of 40 d for the inflammation to subside and the lung epithelia to resemble the non-exposed condition...
October 20, 2016: Respiratory Research
Mina O Seedhom, Heather D Hickman, Jiajie Wei, Alexandre David, Jonathan W Yewdell
We describe the in vivo ribopuromycylation (RPM) method, which uses a puromycin-specific Ab to fluorescently label ribosome-bound puromycylated nascent chains, enabling measurement of translational activity via immunohistochemistry or flow cytometry. Tissue staining provides a unique view of virus-induced activation of adaptive, innate, and stromal immune cells. RPM flow precisely quantitates virus-induced activation of lymphocytes and innate immune cells, and it provides a unique measure of immune cell deactivation and quiescence...
August 15, 2016: Journal of Immunology: Official Journal of the American Association of Immunologists
Vijaykumar Chennupati, Ute Koch, Manuel Coutaz, Leonardo Scarpellino, Fabienne Tacchini-Cottier, Sanjiv A Luther, Freddy Radtke, Dietmar Zehn, H Robson MacDonald
Although Notch signaling plays important roles in lineage commitment and differentiation of multiple cell types including conventional T cells, nothing is currently known concerning Notch function in innate-like T cells. We have found that the homeostasis of several well-characterized populations of innate-like T cells including invariant NKT cells (iNKT), CD8ααTCRαβ small intestinal intraepithelial lymphocytes, and innate memory phenotype CD8 T cells is controlled by Notch. Notch selectively regulates hepatic iNKT cell survival via tissue-restricted control of B cell lymphoma 2 and IL-7Rα expression...
August 1, 2016: Journal of Immunology: Official Journal of the American Association of Immunologists
Kristin R Renkema, June-Yong Lee, You Jeong Lee, Sara E Hamilton, Kristin A Hogquist, Stephen C Jameson
Previous studies have revealed that a population of innate memory CD8(+) T cells is generated in response to IL-4, first appearing in the thymus and bearing high expression levels of Eomesodermin (Eomes) but not T-bet. However, the antigen specificity and functional properties of these cells is poorly defined. In this study, we show that IL-4 regulates not only the frequency and function of innate memory CD8(+) T cells, but also regulates Eomes expression levels and functional reactivity of naive CD8(+) T cells...
June 27, 2016: Journal of Experimental Medicine
Silvain Pinaud, Julien Portela, David Duval, Fanny C Nowacki, Marie-Aude Olive, Jean-François Allienne, Richard Galinier, Nolwenn M Dheilly, Sylvie Kieffer-Jaquinod, Guillaume Mitta, André Théron, Benjamin Gourbal
Discoveries made over the past ten years have provided evidence that invertebrate antiparasitic responses may be primed in a sustainable manner, leading to the failure of a secondary encounter with the same pathogen. This phenomenon called "immune priming" or "innate immune memory" was mainly phenomenological. The demonstration of this process remains to be obtained and the underlying mechanisms remain to be discovered and exhaustively tested with rigorous functional and molecular methods, to eliminate all alternative explanations...
January 2016: PLoS Pathogens
Elfi Töpfer, Diana Boraschi, Paola Italiani
Recent findings in the field of immune memory have demonstrated that B and T cell mediated immunity following infections are enhanced by the so-called trained immunity. This effect has been most extensively investigated for the tuberculosis vaccine strain Bacillus Calmette-Guérin (BCG). Epidemiological studies suggest that this vaccine is associated with a substantial reduction in overall child mortality that cannot be solely explained by prevention of the target disease but that it seems to rely on inducing resistance to other infections...
2015: Journal of Immunology Research
Tom Hartwig, Stanislav Pantelyushin, Andrew L Croxford, Paulina Kulig, Burkhard Becher
Conventional αβ T cells have the ability to form a long-lasting resident memory T-cell (TRM ) population in nonlymphoid tissues after encountering foreign antigen. Conversely, the concept of 'innate memory', where the ability of nonadaptive branches of the immune system to deliver a rapid, strengthened immune response upon reinfection or rechallenge, is just emerging. Using the αβ T-cell-independent Aldara psoriasis mouse model in combination with genetic fate-mapping and reporter systems, we identified a subset of γδ T cells in mice that is capable of establishing a long-lived memory population in the skin...
November 2015: European Journal of Immunology
Wenhao Chen, Rafik M Ghobrial, Xian C Li
Memory cells are the products of immune responses but also exert significant impact on subsequent immunity and immune tolerance, thus placing them in a unique position in transplant research. Memory cells are heterogeneous, including not only memory T cells but also memory B cells and innate memory cells. Memory cells are a critical component of protective immunity against invading pathogens, especially in immunosuppressed patients, but they also mediate graft loss and tolerance resistance. Recent studies suggest that some memory cells unexpectedly act as regulatory cells, promoting rather than hindering transplant survival...
October 2015: Transplantation
Luc Van Kaer
A hallmark of the antigen-specific B and T lymphocytes of the adaptive immune system is their capacity to "remember" pathogens long after they are first encountered, a property that forms the basis for effective vaccine development. However, studies in mice have provided strong evidence that some naive T cells can develop characteristics of memory T cells in the absence of foreign antigen encounters. Such innate memory T cells may develop in response to lymphopenia or the presence of high levels of the cytokine IL-4, and have also been identified in unmanipulated animals, a phenomenal referred to as "virtual memory...
July 2015: European Journal of Immunology
Florence Jacomet, Emilie Cayssials, Sara Basbous, Anaïs Levescot, Nathalie Piccirilli, Deborah Desmier, Aurélie Robin, Anne Barra, Christine Giraud, François Guilhot, Lydia Roy, André Herbelin, Jean-Marc Gombert
Polyclonal CD8(+) T cells, with a marked innate/memory phenotype, high eomesodermin (Eomes) expression, and the capacity to generate IFN-γ rapidly without prior exposure to antigen, have been described in mice. However, even though a pool of human CD8(+) T cells expressing killer Ig-like receptors (KIRs) was recently documented, the existence of a human equivalent of murine innate/memory CD8(+) T cells remains to be established. Here, we provide evidence for a population of KIR/NKG2A(+) CD8(+) T cells in healthy human adults sharing the same features, namely increased Eomes expression, prompt IFN-γ production in response to innate-like stimulation by IL-12+IL-18, and a potent antigen-independent cytotoxic activity along with a preferential terminally differentiated effector memory phenotype...
July 2015: European Journal of Immunology
Stephen C Jameson, You Jeong Lee, Kristin A Hogquist
Memory T cells are usually considered to be a feature of a successful immune response against a foreign antigen, and such cells can mediate potent immunity. However, in mice, alternative pathways have been described, through which naïve T cells can acquire the characteristics and functions of memory T cells without encountering specific foreign antigen or the typical signals required for conventional T cell differentiation. Such cells reflect a response to the internal rather the external environment, and hence such cells are called innate memory T cells...
2015: Advances in Immunology
Amlan Kanti Ghosh, Debolina Sinha, Subhadeep Mukherjee, Ratna Biswas, Tapas Biswas
Nonconventional innate memory CD8(+) T cells characteristically expressing CD44, CD122, eomesodermin (Eomes) and promyelocytic leukemia zinc finger (PLZF) were derived in culture from CD4(+)CD8(+) double positive (DP) thymocytes of normal BALB/c and C57BL/6 mice. These culture-differentiated cells constitutively express toll-like receptor (TLR)4 and release interferon (IFN)-γ and interleukin (IL)-10. We show the TLR4-ligand lipopolysaccharide (LPS) stimulate the TLR and up-regulate IFN-γ skewing the cells towards type 1 polarization...
May 2015: Cytokine
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