2 Immune Response and Host Defense in the Nursing-Home Patient

2015 ◽  
pp. 12-29
Author(s):  
J. Kelly Smith
Keyword(s):  
Immune Response ◽  
Nursing Home ◽  
Host Defense ◽  
Nursing Home Patient

Adverse Effects of Anticoagulation and Antiplatelet Therapies in a Frail Nursing Home Patient

2016 ◽  
Vol 17 (3) ◽  
pp. B3
Author(s):  
Scott Hanson ◽  
Scott Hanson ◽  
Allysa Houfek ◽  
Erin Nelson ◽  
Phoung Nguyen ◽  
...  
Keyword(s):  
Nursing Home ◽  
Adverse Effects ◽  
Nursing Home Patient

scholarly journals Megakaryocyte derived immune-stimulating cells regulate host-defense immunity against bacterial pathogens

2021 ◽  
Author(s):  
Jin Wang ◽  
Jiayi Xie ◽  
Xue Han ◽  
Daosong Wang ◽  
Minqi Chen ◽  
...  
Keyword(s):  
Immune Response ◽  
T Cell ◽  
Bacterial Infection ◽  
Host Defense ◽  
T Cell Activation ◽  
Cell Activation ◽  
Hematopoietic Stem ◽  
Bacterial Response ◽  
Stem Cell Quiescence ◽  
Express Cell

Megakaryocytes (MKs) continuously produce platelets in bone marrow to support hemostasis. However, MKs also play roles beyond thrombopoiesis as they regulate hematopoietic stem cell quiescence and erythropoiesis, which suggests the functional heterogeneity of MKs. Here, using single-cell sequencing we identified an MK-derived immune-stimulating cell (MDIC) population, which plays an important role in host-protective response against bacteria. In contrast to platelet-generating MKs, MDICs highly express cell migration, immune-modulatory, and response genes. Upon Listeria (L.) monocytogenes infection, MDICs egress to circulation and infiltrate into the spleen, liver and lung. MDICs interact with myeloid cells to promote their migration and tissue infiltration. More importantly, MDICs stimulate phagocytosis of macrophages and neutrophils by producing TNFα and IL-6 and facilitating antigen-specific T cell activation via IL-6 to enhance anti-bacterial response. Ablation of MKs reduced innate immune response and compromised T cell activation in spleen and liver, impairs the anti-bacterial effects in mice under L. monocytogenes challenge. Finally, infection-induced emergency megakaryopoiesis efficiently stimulated MDICs generation upon bacterial infection. Overall, we identify MDICs as a novel MK subpopulation, which regulates host-defense immune response against bacterial infection.

scholarly journals Differential Requirements for Mediator Complex Subunits in Drosophila melanogaster Host Defense Against Fungal and Bacterial Pathogens

2021 ◽  
Vol 11 ◽  
Author(s):  
Chuqin Huang ◽  
Rui Xu ◽  
Samuel Liégeois ◽  
Di Chen ◽  
Zi Li ◽  
...  
Keyword(s):  
Immune Response ◽  
Host Defense ◽  
Bacterial Infections ◽  
Fungal Infections ◽  
Transcriptional Response ◽  
Erwinia Carotovora ◽  
Mediator Complex ◽  
Toll Pathway ◽  
Metarhizium Robertsii ◽  
Immune Factor

The humoral immune response to bacterial or fungal infections in Drosophila relies largely on a transcriptional response mediated by the Toll and Immune deficiency NF-κB pathways. Antimicrobial peptides are potent effectors of these pathways and allow the organism to attack invading pathogens. Dorsal-related Immune Factor (DIF), a transcription factor regulated by the Toll pathway, is required in the host defense against fungal and some Gram-positive bacterial infections. The Mediator complex is involved in the initiation of transcription of most RNA polymerase B (PolB)-dependent genes by forming a functional bridge between transcription factors bound to enhancer regions and the gene promoter region and then recruiting the PolB pre-initiation complex. Mediator is formed by several modules that each comprises several subunits. The Med17 subunit of the head module of Mediator has been shown to be required for the expression of Drosomycin, which encodes a potent antifungal peptide, by binding to DIF. Thus, Mediator is expected to mediate the host defense against pathogens controlled by the Toll pathway-dependent innate immune response. Here, we first focus on the Med31 subunit of the middle module of Mediator and find that it is required in host defense against Aspergillus fumigatus, Enterococcus faecalis, and injected but not topically-applied Metarhizium robertsii. Thus, host defense against M. robertsii requires Dif but not necessarily Med31 in the two distinct infection models. The induction of some Toll-pathway-dependent genes is decreased after a challenge of Med31 RNAi-silenced flies with either A. fumigatus or E. faecalis, while these flies exhibit normal phagocytosis and melanization. We have further tested most Mediator subunits using RNAi by monitoring their survival after challenges to several other microbial infections known to be fought off through DIF. We report that the host defense against specific pathogens involves a distinct set of Mediator subunits with only one subunit for C. glabrata or Erwinia carotovora carotovora, at least one for M. robertsii or a somewhat extended repertoire for A. fumigatus (at least eight subunits) and E. faecalis (eight subunits), with two subunits, Med6 and Med11 being required only against A. fumigatus. Med31 but not Med17 is required in fighting off injected M. robertsii conidia. Thus, the involvement of Mediator in Drosophila innate immunity is more complex than expected.

scholarly journals β-Defensin Strengthens Antimicrobial Peritoneal Mast Cell Response

2020 ◽  
Vol 2020 ◽  
pp. 1-14 ◽  
Author(s):  
Justyna Agier ◽  
Ewa Brzezińska-Błaszczyk ◽  
Sylwia Różalska ◽  
Magdalena Wiktorska ◽  
Sebastian Wawrocki ◽  
...  
Keyword(s):  
Immune Response ◽  
Host Defense ◽  
Peritoneal Mast Cell ◽  
Pathogen Defense ◽  
Migratory Response ◽  
Mrna And Protein Expression ◽  
Molecular Patterns ◽  
Defense Molecules ◽  
Ongoing Infection ◽  
Inducible Gene

Mast cells (MCs) are engaged in the processes of host defense, primarily via the presence of receptors responsible for the detection of pathogen-associated molecular patterns (PAMPs). Since BDs are exclusively host defense molecules, and MCs can elicit the antimicrobial response, this study is aimed at determining whether BDs might be involved in MC pathogen defense. We found that defensin BD-2 significantly augments the mRNA and protein expression of Toll-like receptors (TLRs) and retinoic acid-inducible gene-I-like receptor (RLR) essential for the detection of viral molecules, i.e., TLR3, TLR7, TLR9, and RIG-I in mature tissue rat peritoneal MCs (PMCs). We established that BD-2 might stimulate PMCs to release proinflammatory and immunoregulatory mediators and to induce a migratory response. Presented data on IgE-coated PMC upon BD-2 treatment suggest that in the case of allergies, there is an enhanced MC immune response and cell influx to the site of the ongoing infection. In conclusion, our data highlight that BD-2 might strongly influence MC features and activity, mainly by strengthening their role in the inflammatory mechanisms and controlling the activity of cells participating in antimicrobial processes.

scholarly journals Immune Immunomodulation in Coronavirus Disease 2019 (COVID-19): Strategic Considerations for Personalized Therapeutic Intervention

2020 ◽  
Author(s):  
Mark W Hall ◽  
Ila Joshi ◽  
Luis Leal ◽  
Eng Eong Ooi
Keyword(s):  
Immune Response ◽  
Critical Illness ◽  
Severe Acute Respiratory Syndrome ◽  
Systemic Inflammation ◽  
Host Defense ◽  
Shortest Path ◽  
Immune Suppression ◽  
Host Response ◽  
Repair Mechanisms ◽  
Anticytokine Therapy

Abstract We are learning that the host response to severe acute respiratory syndrome coronavirus 2 ( SARS-CoV-2) infection is complex and highly dynamic. Effective initial host defense in the lung is associated with mild symptoms and disease resolution. Viral evasion of the immune response can lead to refractory alveolar damage, ineffective lung repair mechanisms, and systemic inflammation with associated organ dysfunction. The immune response in these patients is highly variable and can include moderate to severe systemic inflammation and/or marked systemic immune suppression. There is unlikely to be a “one size fits all” approach to immunomodulation in patients with coronavirus disease 2019 (COVID-19). We believe that a personalized, immunophenotype-driven approach to immunomodulation that may include anticytokine therapy in carefully selected patients and immunostimulatory therapies in others is the shortest path to success in the study and treatment of patients with critical illness due to COVID-19.

scholarly journals Haematophagous arthropod saliva and host defense system: a tale of tear and blood

2005 ◽  
Vol 77 (4) ◽  
pp. 665-693 ◽  
Author(s):  
Bruno B. Andrade ◽  
Clarissa R. Teixeira ◽  
Aldina Barral ◽  
Manoel Barral-Netto
Keyword(s):  
Immune Response ◽  
Immune Responses ◽  
Host Defense ◽  
Blood Meal ◽  
Disease Transmission ◽  
Blood Feeding ◽  
Defense System ◽  
Current Information ◽  
System A ◽  
Host Defense System

The saliva from blood-feeding arthropod vectors is enriched with molecules that display diverse functions that mediate a successful blood meal. They function not only as weapons against host's haemostatic, inflammatory and immune responses but also as important tools to pathogen establishment. Parasites, virus and bacteria taking advantage of vectors' armament have adapted to facilitate their entry in the host. Today, many salivary molecules have been identified and characterized as new targets to the development of future vaccines. Here we focus on current information on vector's saliva and the molecules responsible to modify host's hemostasis and immune response, also regarding their role in disease transmission.

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