Search results for "Immune system"
showing 10 items of 2885 documents
Host plant variation plastically impacts different traits of the immune system of a phytophagous insect
2011
Summary 1. Host plant quality affects herbivorous insect performance and consequently their susceptibility to natural enemies. Recently, it has been hypothesized that the immune function of herbivorous insects can be altered by their host plant, thus generating variation in their susceptibility to entomopathogens. Previous studies testing this hypothesis provided contradictory outcomes, mainly as a result of the differences in methodology such as measuring a single-immune parameter rather than considering trade-off-mediated interactions between immune defence systems of the insect. Here, we hypothesized that plant-mediated changes in insect immunity could result from the alteration of physi…
An experimental heat wave changes immune defense and life history traits in a freshwater snail
2013
The predicted increase in frequency and severity of heat waves due to climate change is expected to alter disease dynamics by reducing hosts' ability to resist infections. This could take place via two different mechanisms: (1) through general reduction in hosts' performance under harsh environmental conditions and/or (2) through altered resource allocation that reduces expression of defense traits in order to maintain other traits. We tested these alternative hypotheses by measuring the effect of an experimental heat wave (25 vs. 15°C) on the constitutive level of immune defense (hemocyte concentration, phenoloxidase [PO]‐like activity, antibacterial activity of hemolymph), and life histor…
Consequence of Histoincompatibility beyond GvH-Reaction in Cytomegalovirus Disease Associated with Allogeneic Hematopoietic Cell Transplantation: Cha…
2021
Hematopoietic cell (HC) transplantation (HCT) is the last resort to cure hematopoietic malignancies that are refractory to standard therapies. Hematoablative treatment aims at wiping out tumor cells as completely as possible to avoid leukemia/lymphoma relapse. This treatment inevitably co-depletes cells of hematopoietic cell lineages, including differentiated cells that constitute the immune system. HCT reconstitutes hematopoiesis and thus, eventually, also antiviral effector cells. In cases of an unrelated donor, that is, in allogeneic HCT, HLA-matching is performed to minimize the risk of graft-versus-host reaction and disease (GvHR/D), but a mismatch in minor histocompatibility antigens …
Cognate HLA absence in trans diminishes human NK cell education
2016
NK cells are innate lymphocytes with protective functions against viral infections and tumor formation. Human NK cells carry inhibitory killer cell Ig-like receptors (KIRs), which recognize distinct HLAs. NK cells with KIRs for self-HLA molecules acquire superior cytotoxicity against HLA– tumor cells during education for improved missing-self recognition. Here, we reconstituted mice with human hematopoietic cells from donors with homozygous KIR ligands or with a mix of hematopoietic cells from these homozygous donors, allowing assessment of the resulting KIR repertoire and NK cell education. We found that co-reconstitution with 2 KIR ligand–mismatched compartments did not alter the frequenc…
Lepidopteran species have a variety of defence strategies against bacterial infections
2017
The insect immune system has versatile ways of coping with microbial insults. Currently, innate immune priming has been described in several invertebrates, and the first insights into its mechanistic basis have been described. Here we studied infections with two different strains of Serratia marcescens bacteria in two different Lepidopteran hosts. The results reveal fundamental differences between the two hosts, a well-known model organism Galleria mellonella and a non-model species Arctia plantaginis. They differ in their strategies for resisting oral infections; priming their defences against a recurring sepsis; and upregulating immunity related genes as a response to the specific pathoge…
COVID-19 severity associates with pulmonary redistribution of CD1c+ DCs and inflammatory transitional and nonclassical monocytes
2020
SARS-CoV-2 is responsible for the development of coronavirus disease 2019 (COVID-19) in infected individuals, who can either exhibit mild symptoms or progress toward a life-threatening acute respiratory distress syndrome (ARDS). Exacerbated inflammation and dysregulated immune responses involving T and myeloid cells occur in COVID-19 patients with severe clinical progression. However, the differential contribution of specific subsets of dendritic cells and monocytes to ARDS is still poorly understood. In addition, the role of CD8+ T cells present in the lung of COVID-19 patients and relevant for viral control has not been characterized. Here, we have studied the frequencies and activation p…
Assessment of tumor-infiltrating TCRV γ 9V δ 2 γδ lymphocyte abundance by deconvolution of human cancers microarrays
2017
Most human blood γδ cells are cytolytic TCRVγ9Vδ2+lymphocytes with antitumor activity. They are currently investigated in several clinical trials of cancer immunotherapy but so far, their tumor infiltration has not been systematically explored across human cancers. Novel algorithms allowing the deconvolution of bulk tumor transcriptomes to find the relative proportions of infiltrating leucocytes, such as CIBERSORT, should be appropriate for this aim but in practice they fail to accurately recognize γδ T lymphocytes. Here, by implementing machine learning from microarray data, we first improved the computational identification of blood-derived TCRVγ9Vδ2+γδ lymphocytes and then appl…
Human ectonucleotidase-expressing CD25 high Th17 cells accumulate in breast cancer tumors and exert immunosuppressive functions
2015
IF 7.644; International audience; Th17 cells contribute to the development of some autoimmune and allergic diseases by driving tissue inflammation. However, the function of Th17 cells during cancer progression remains controversial. Here, we show that human memory CD25(high) Th17 cells suppress T cell immunity in breast cancer. Ectonucleotidase-expressing Th17 cells accumulated in breast cancer tumors and suppressed CD4(+) and CD8(+) T cell activation. These cells expressed both Ror gamma t and Foxp3 genes and secreted Th17 related cytokines. We further found that CD39 ectonucleotisase expression on tumor-infiltrating Th17 cells was driven by TGF-beta and IL-6. Finally, immunohistochemical …
CCR7 on CD4+ T Cells Plays a Crucial Role in the Induction of Experimental Autoimmune Encephalomyelitis
2018
Abstract Multiple sclerosis (MS) is the most common chronic inflammatory demyelinating disease of the CNS. Myelin-specific CD4+ Th lymphocytes are known to play a major role in both MS and its animal model experimental autoimmune encephalomyelitis (EAE). CCR7 is a critical element for immune cell trafficking and recirculation, that is, lymph node homing, under homeostatic conditions; blocking CCR7+ central memory cells from egress of lymph nodes is a therapeutic approach in MS. To define the effect of CD4+ T cell–specific constitutive deletion of CCR7 in the priming and effector phase in EAE, we used an active EAE approach in T cell reconstituted Rag1−/− mice, as well as adoptive transfer E…
From bedside to bench: The missing brick for patients with fungal sepsis
2016
We read with great interest the article by Spec et al. [1] investigating the immunophenotype of T cells from patients with Candida spp. sepsis. This is the first observational study describing the altered immune response of patients with candidemia. The authors included non-neutropenic critically ill patients with candidemia and non-septic controls, and excluded patients with human immunodeficiency virus infection, who had undergone solid or bone marrow transplantation or with other known causes of impaired immune response. The authors hypothesized that their findings may help explain why patients with fungal sepsis show a high mortality despite appropriate antifungal therapy. In our opinio…