Activation of the complement system by pathogenic fungi.

Fungi have been studied as prototype activators of the complement cascade since the early 1900s. More recently, attention has focused on the role of the complement system in the pathogenesis of fungal infections. The interactions of Cryptococcus neoformans and Candida albicans with the complement system are the most widely characterized; however, all pathogenic fungi examined to date have the ability to initiate the complement cascade. The molecular mechanisms for initiation and regulation of the complement cascade differ from one fungus to another, most likely reflecting differences in the structure of the outer layers of the cell wall. The molecular bases for such differences remain to be identified. Studies of mycoses in experimental animals with induced or congenital deficiencies in the complement system demonstrate that complement is an important innate system for control of fungal infection. Contributions to host resistance include opsonization and generation of inflammatory mediators. Inflammation induced by chemotactic products of the complement system may contribute to the pathogenesis of some fungal infections.

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Complement Activation Contributes to Severe Acute Respiratory Syndrome Coronavirus Pathogenesis

mBio ◽

10.1128/mbio.01753-18 ◽

2018 ◽

Vol 9 (5) ◽

Cited By ~ 224

Author(s):

Lisa E. Gralinski ◽

Timothy P. Sheahan ◽

Thomas E. Morrison ◽

Vineet D. Menachery ◽

Kara Jensen ◽

...

Keyword(s):

Severe Acute Respiratory Syndrome ◽

Host Defense ◽

Complement System ◽

Complement Activation ◽

Fungal Infections ◽

Central Component ◽

Lung Pathology ◽

Inflammatory Monocytes ◽

The Complement System

ABSTRACT Acute respiratory distress syndrome (ARDS) is immune-driven pathologies that are observed in severe cases of severe acute respiratory syndrome coronavirus (SARS-CoV) infection. SARS-CoV emerged in 2002 to 2003 and led to a global outbreak of SARS. As with the outcome of human infection, intranasal infection of C57BL/6J mice with mouse-adapted SARS-CoV results in high-titer virus replication within the lung, induction of inflammatory cytokines and chemokines, and immune cell infiltration within the lung. Using this model, we investigated the role of the complement system during SARS-CoV infection. We observed activation of the complement cascade in the lung as early as day 1 following SARS-CoV infection. To test whether this activation contributed to protective or pathologic outcomes, we utilized mice deficient in C3 (C3–/–), the central component of the complement system. Relative to C57BL/6J control mice, SARS-CoV-infected C3–/– mice exhibited significantly less weight loss and less respiratory dysfunction despite equivalent viral loads in the lung. Significantly fewer neutrophils and inflammatory monocytes were present in the lungs of C3–/– mice than in C56BL/6J controls, and subsequent studies revealed reduced lung pathology and lower cytokine and chemokine levels in both the lungs and the sera of C3–/– mice than in controls. These studies identify the complement system as an important host mediator of SARS-CoV-induced disease and suggest that complement activation regulates a systemic proinflammatory response to SARS-CoV infection. Furthermore, these data suggest that SARS-CoV-mediated disease is largely immune driven and that inhibiting complement signaling after SARS-CoV infection might function as an effective immune therapeutic. IMPORTANCE The complement system is a critical part of host defense to many bacterial, viral, and fungal infections. It works alongside pattern recognition receptors to stimulate host defense systems in advance of activation of the adaptive immune response. In this study, we directly test the role of complement in SARS-CoV pathogenesis using a mouse model and show that respiratory disease is significantly reduced in the absence of complement even though viral load is unchanged. Complement-deficient mice have reduced neutrophilia in their lungs and reduced systemic inflammation, consistent with the observation that SARS-CoV pathogenesis is an immune-driven disease. These data suggest that inhibition of complement signaling might be an effective treatment option following coronavirus infection.

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ROLE OF THE COMPLEMENT SYSTEM IN GRAFT REJECTIONS IN EXPERIMENTAL ANIMALS AND MAN*

Annals of the New York Academy of Sciences ◽

10.1111/j.1749-6632.1966.tb12887.x ◽

2006 ◽

Vol 129 (1) ◽

pp. 673-713 ◽

Cited By ~ 57

Author(s):

Henry Gewurz ◽

D. Scott Clark ◽

Joann Finstad ◽

William D. Kelly ◽

Richard L. Varco ◽

...

Keyword(s):

Complement System ◽

Experimental Animals ◽

The Complement System

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The Role of Fungi in the Cocoa Production Chain and the Challenge of Climate Change

Journal of Fungi ◽

10.3390/jof7030202 ◽

2021 ◽

Vol 7 (3) ◽

pp. 202

Author(s):

Johannes Delgado-Ospina ◽

Junior Bernardo Molina-Hernández ◽

Clemencia Chaves-López ◽

Gianfranco Romanazzi ◽

Antonello Paparella

Keyword(s):

Climate Change ◽

Fungal Infections ◽

Close Association ◽

Pathogenic Fungi ◽

Fungal Species ◽

Mitigation Strategies ◽

Plant Diseases ◽

Production Chain ◽

Cocoa Production

Background: The role of fungi in cocoa crops is mainly associated with plant diseases and contamination of harvest with unwanted metabolites such as mycotoxins that can reach the final consumer. However, in recent years there has been interest in discovering other existing interactions in the environment that may be beneficial, such as antagonism, commensalism, and the production of specific enzymes, among others. Scope and approach: This review summarizes the different fungi species involved in cocoa production and the cocoa supply chain. In particular, it examines the presence of fungal species during cultivation, harvest, fermentation, drying, and storage, emphasizing the factors that possibly influence their prevalence in the different stages of production and the health risks associated with the production of mycotoxins in the light of recent literature. Key findings and conclusion: Fungi associated with the cocoa production chain have many different roles. They have evolved in a varied range of ecosystems in close association with plants and various habitats, affecting nearly all the cocoa chain steps. Reports of the isolation of 60 genera of fungi were found, of which only 19 were involved in several stages. Although endophytic fungi can help control some diseases caused by pathogenic fungi, climate change, with increased rain and temperatures, together with intensified exchanges, can favour most of these fungal infections, and the presence of highly aggressive new fungal genotypes increasing the concern of mycotoxin production. For this reason, mitigation strategies need to be determined to prevent the spread of disease-causing fungi and preserve beneficial ones.

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Analysis of the Role of Bradysiaimpatiens (Diptera: Sciaridae) as a Vector Transmitting Peanut Stunt Virus on the Model Plant Nicotiana benthamiana

Cells ◽

10.3390/cells10061546 ◽

2021 ◽

Vol 10 (6) ◽

pp. 1546

Author(s):

Marta Budziszewska ◽

Patryk Frąckowiak ◽

Aleksandra Obrępalska-Stęplowska

Keyword(s):

Nicotiana Benthamiana ◽

Molecular Mechanisms ◽

Virus Transmission ◽

Pathogenic Fungi ◽

Economic Losses ◽

Fungus Gnats ◽

Droplet Pcr ◽

Viral Coat ◽

Peanut Stunt Virus

Bradysia species, commonly known as fungus gnats, are ubiquitous in greenhouses, nurseries of horticultural plants, and commercial mushroom houses, causing significant economic losses. Moreover, the insects from the Bradysia genus have a well-documented role in plant pathogenic fungi transmission. Here, a study on the potential of Bradysia impatiens to acquire and transmit the peanut stunt virus (PSV) from plant to plant was undertaken. Four-day-old larvae of B. impatiens were exposed to PSV-P strain by feeding on virus-infected leaves of Nicotiana benthamiana and then transferred to healthy plants in laboratory conditions. Using the reverse transcription-polymerase chain reaction (RT-PCR), real-time PCR (RT-qPCR), and digital droplet PCR (RT-ddPCR), the PSV RNAs in the larva, pupa, and imago of B. impatiens were detected and quantified. The presence of PSV genomic RNA strands as well as viral coat protein in N. benthamiana, on which the viruliferous larvae were feeding, was also confirmed at the molecular level, even though the characteristic symptoms of PSV infection were not observed. The results have shown that larvae of B. impatiens could acquire the virus and transmit it to healthy plants. Moreover, it has been proven that PSV might persist in the insect body transstadially. Although the molecular mechanisms of virion acquisition and retention during insect development need further studies, this is the first report on B. impatiens playing a potential role in plant virus transmission.

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Special Issue: The Role of Complement in Cancer Immunotherapy

Antibodies ◽

10.3390/antib10030029 ◽

2021 ◽

Vol 10 (3) ◽

pp. 29

Author(s):

Ronald P. Taylor

Keyword(s):

Cancer Immunotherapy ◽

Complement System ◽

Immune Defense ◽

Special Issue ◽

The Complement System ◽

Critical Aspects

The complement system plays an important role in critical aspects of immune defense and in the maintenance of homeostasis in the bloodstream, as well as in essentially all tissues and organs [...]

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