The interaction of macrophage receptors with bacterial ligands

2006 ◽  
Vol 8 (28) ◽  
pp. 1-25 ◽  
Author(s):  
Annette Plüddemann ◽  
Subhankar Mukhopadhyay ◽  
Siamon Gordon
Keyword(s):  
Immune Response ◽  
Early Recognition ◽  
Adaptive Immune Response ◽  
Innate Immune ◽  
Surface Proteins ◽  
Scavenger Receptors ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Macrophage Receptors

Innate immune receptors play a key role in the early recognition of invading bacterial pathogens and initiate the crucial innate immune response. The diverse macrophage receptors recognise Gram-positive and Gram-negative bacteria via conserved structures on the bacterial surface and facilitate phagocytosis and/or signalling, providing the trigger for the adaptive immune response. These receptors include scavenger receptors, C-type lectins, integrins, Toll-like receptors and siglecs. The bacterial ligands generally recognised by these receptors range from lipopolysaccharides on Gram-negative bacteria to peptidoglycan and lipoteichoic acid on Gram-positive bacteria. However, emerging evidence indicates that bacterial proteins are also important ligands; for example, surface proteins from Neisseria meningitidis have been shown to be ligands for class A scavenger receptors. In addition, a group of cytosolic receptors, the NBS-LRR proteins, have been implicated in recognition of bacterial breakdown products. It is becoming increasingly apparent that macrophage receptors can act in conjunction with one another to deliver an appropriate response.

scholarly journals Immune Responses to Gram-Negative Bacteria in Hemolymph of the Chinese Horseshoe Crab, Tachypleus tridentatus

2021 ◽  
Vol 11 ◽  
Author(s):  
Wei-Feng Wang ◽  
Xiao-Yong Xie ◽  
Kang Chen ◽  
Xiu-Li Chen ◽  
Wei-Lin Zhu ◽  
...  
Keyword(s):  
Immune Response ◽  
Horseshoe Crab ◽  
Mapk Signaling ◽  
Innate Immune ◽  
Coagulation Cascade ◽  
Gram Negative Bacteria ◽  
Fossil Species ◽  
Living Fossil ◽  
Gram Negative ◽  
Tachypleus Tridentatus

Chinese horseshoe crab, Tachypleus tridentatus, is an ancient marine arthropod with a long evolutionary history. As a kind of living fossil species, the pathogen defenses of horseshoe crabs entirely depend on the innate immune system. Although, there are abundant immune molecules found in the horseshoe crab hemolymph, the biological mechanisms underlying their abilities of distinguishing and defending against invading microbes are still unclear. In this study, we used high-throughput sequencing at mRNA and protein levels and bioinformatics analysis methods to systematically analyze the innate immune response to Gram-negative bacteria in hemolymph of Chinese horseshoe crab. These results showed that many genes in the complement and coagulation cascades, Toll, NF-κB, C-type lectin receptor, JAK-STAT, and MAPK signaling pathways, and antimicrobial substances were activated at 12 and 24 h post-infection, suggesting that Gram-negative bacteria could activate the hemolymph coagulation cascade and antibacterial substances release via the above pathways. In addition, we conjectured that Toll and NF-κB signaling pathway were most likely to participate in the immune response to Gram-negative bacteria in hemolymph of horseshoe crab through an integral signal cascade. These findings will provide a useful reference for exploring the ancient original innate immune mechanism.

Blood leukocyte transcriptomes in gram-positive and gram-negative community-acquired pneumonia

2021 ◽  
pp. 2101856
Author(s):  
Liza Pereverzeva ◽  
Fabrice Uhel ◽  
Hessel Peters Sengers ◽  
Joe Butler ◽  
Lonneke A. van Vught ◽  
...  
Keyword(s):  
Immune Response ◽  
Host Response ◽  
Host Immune Response ◽  
Community Acquired Pneumonia ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Icu Admission ◽  
Blood Leukocyte ◽  
Response Biomarkers

BackgroundGram-positive and Gram-negative bacteria are the most common causative pathogens in community-acquired pneumonia (CAP) on the intensive care unit (ICU). The aim of this study was to determine whether the host immune response differs between Gram-positive and Gram-negative CAP upon ICU admission.MethodsSixteen host response biomarkers providing insight in pathophysiological mechanisms implicated in sepsis and blood leukocyte transcriptomes were analysed in patients with CAP upon ICU admission in two tertiary hospitals in the Netherlands.Results309 patients with CAP with a definite or probable likelihood (determined by predefined criteria) were included. A causative pathogen was determined in 74.4% of admissions. Patients admitted with Gram-positive CAP (n=90) were not different from those admitted with Gram-negative CAP (n=75) regarding demographics, chronic comorbidities, severity of disease and mortality. Host response biomarkers reflective of systemic inflammation, coagulation activation and endothelial cell function, as well as blood leukocytes transcriptomes, were largely similar between Gram-positive and Gram-negative CAP. Blood leukocyte transcriptomes were also similar in Gram-positive and Gram-negative CAP in two independent validation cohorts. On a pathogen-specific level, Streptococcus pneumoniae and Escherichia coli induced the most distinct host immune response.ConclusionOutcome and host response are similar in critically ill patients with CAP due to Gram-positive bacteria compared to Gram-negative bacteria.

scholarly journals Innate Immune Responses in Peptidoglycan Recognition Protein L-Deficient Mice

2004 ◽  
Vol 24 (18) ◽  
pp. 7949-7957 ◽  
Author(s):  
Min Xu ◽  
Zhien Wang ◽  
Richard M. Locksley
Keyword(s):  
Critical Role ◽  
Peritoneal Macrophages ◽  
Innate Immune ◽  
Immune Recognition ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Necrosis Factor Alpha ◽  
Gram Negative ◽  
Peptidoglycan Recognition Protein ◽  
Deficient Mice

ABSTRACT Peptidoglycan recognition proteins (PGRPs) constitute a family of innate immune recognition molecules. In Drosophila, distinct PGRPs bind to peptidoglycans on gram-positive or gram-negative bacteria and provide essential signals upstream of the Toll and Imd pathways required for immunity against infection. Four PGRPs, PGRP-L, -S, -Iα, and -Iβ, are expressed from three genes in mammals. In this paper, we provide direct evidence that the longest family member, PGRP-L, is a secreted serum protein with the capacity to multimerize. Using gene targeting to create PGRP-L-deficient mice, we demonstrate little contribution by PGRP-L to systemic challenge using gram-negative bacteria (Escherichia coli, slightly less susceptible), Gram-positive bacteria (Staphylococcus aureus), or yeast (Candida albicans). Peritoneal macrophages from PGRP-L-deficient mice produced decreased amounts of the inflammatory cytokines interleukin 6 and tumor necrosis factor alpha when stimulated with E. coli or lipopolysaccharide, but comparable amounts when stimulated with S. aureus, C. albicans, or their cell wall components. Additionally, these cells produced similar amounts of cytokines when challenged with gram-positive or -negative peptidoglycans. In contrast to its critical role in immunity in flies, PGRP-L is largely dispensable for mammalian immunity against bacteria and fungi.

scholarly journals Caspase-11 Plays a Protective Role in Pulmonary Acinetobacter baumannii Infection

2017 ◽  
Vol 85 (10) ◽  
Author(s):  
Wei Wang ◽  
Yue Shao ◽  
Shengjun Li ◽  
Na Xin ◽  
Tingxian Ma ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Immune Response ◽  
Acinetobacter Baumannii ◽  
Pulmonary Infection ◽  
Protective Role ◽  
Innate Immune ◽  
Gram Negative Bacteria ◽  
Pathological Changes ◽  
Gram Negative ◽  
Content Type

ABSTRACT Activation of caspase-11 by some Gram-negative bacteria triggers the caspase-1/interleukin 1β (IL-1β) pathway, independent of canonical inflammasomes. Acinetobacter baumannii is a Gram-negative, conditionally pathogenic bacterium that can cause severe pulmonary infection in hospitalized patients. A. baumannii was revealed to activate canonical and noncanonical inflammasome pathways in bone marrow-derived macrophages (BMDMs). Pulmonary infection of caspase-11−/− mice with A. baumannii showed that caspase-11 deficiency impaired A. baumannii clearance, exacerbated pulmonary pathological changes, and enhanced susceptibility to A. baumannii. These data indicate that the caspase-11-mediated innate immune response plays a crucial role in defending against A. baumannii.

scholarly journals Lipoproteins of Gram-Positive Bacteria: Key Players in the Immune Response and Virulence

2016 ◽  
Vol 80 (3) ◽  
pp. 891-903 ◽  
Author(s):  
Minh Thu Nguyen ◽  
Friedrich Götz
Keyword(s):  
Immune Response ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Content Type ◽  
Gram Positive Bacteria ◽  
Key Players ◽  
Toll Like Receptor 2 ◽  
Number Of Publications

SUMMARYSince the discovery in 1973 of the first of the bacterial lipoproteins (Lpp) inEscherichia coli, Braun's lipoprotein, the ever-increasing number of publications indicates the importance of these proteins. Bacterial Lpp belong to the class of lipid-anchored proteins that in Gram-negative bacteria are anchored in both the cytoplasmic and outer membranes and in Gram-positive bacteria are anchored only in the cytoplasmic membrane. In contrast to the case for Gram-negative bacteria, in Gram-positive bacteria lipoprotein maturation and processing are not vital. Physiologically, Lpp play an important role in nutrient and ion acquisition, allowing particularly pathogenic species to better survive in the host. Bacterial Lpp are recognized by Toll-like receptor 2 (TLR2) of the innate immune system. The important role of Lpp in Gram-positive bacteria, particularly in the phylumFirmicutes, as key players in the immune response and pathogenicity has emerged only in recent years. In this review, we address the role of Lpp in signaling and modulating the immune response, in inflammation, and in pathogenicity. We also address the potential of Lpp as promising vaccine candidates.

Differences in innate immune responses upon stimulation with gram-positive and gram-negative bacteria

2006 ◽  
Vol 41 (5) ◽  
pp. 447-454 ◽  
Author(s):  
Konrad Tietze ◽  
Alexander Dalpke ◽  
Sigfried Morath ◽  
Reinier Mutters ◽  
Klaus Heeg ◽  
...  
Keyword(s):  
Immune Responses ◽  
Innate Immune ◽  
Gram Negative Bacteria ◽  
Innate Immune Responses ◽  
Gram Positive ◽  
Gram Negative
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