virulence factor |
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CHEBI:72316 |
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Any toxin secreted by bacteria, viruses, fungi or protozoa enabling them to achieve colonisation of a niche in the host, inhibit or evade the host's immune response, enter and exit cells, or obtain nutrition from the host. |
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This entity has been manually annotated by the ChEBI Team.
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Virulence factors (preferably known as pathogenicity factors or effectors in botany) are cellular structures, molecules and regulatory systems that enable microbial pathogens (bacteria, viruses, fungi, and protozoa) to achieve the following:
colonization of a niche in the host (this includes movement towards and attachment to host cells)
immunoevasion, evasion of the host's immune response
immunosuppression, inhibition of the host's immune response (this includes leukocidin-mediated cell death)
entry into and exit out of cells (if the pathogen is an intracellular one)
obtain nutrition from the host
Specific pathogens possess a wide array of virulence factors. Some are chromosomally encoded and intrinsic to the bacteria (e.g. capsules and endotoxin), whereas others are obtained from mobile genetic elements like plasmids and bacteriophages (e.g. some exotoxins). Virulence factors encoded on mobile genetic elements spread through horizontal gene transfer, and can convert harmless bacteria into dangerous pathogens. Bacteria like Escherichia coli O157:H7 gain the majority of their virulence from mobile genetic elements. Gram-negative bacteria secrete a variety of virulence factors at host–pathogen interface, via membrane vesicle trafficking as bacterial outer membrane vesicles for invasion, nutrition and other cell-cell communications. It has been found that many pathogens have converged on similar virulence factors to battle against eukaryotic host defenses. These obtained bacterial virulence factors have two different routes used to help them survive and grow:
The factors are used to assist and promote colonization of the host. These factors include adhesins, invasins, and antiphagocytic factors. Bacterial flagella that give motility are included in these virulence factors.
The factors, including toxins, hemolysins and proteases, bring damage to the host. |
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Seidler NW (2013) GAPDH, as a virulence factor. Advances in experimental medicine and biology 985, 149-178 [PubMed:22851449] [show Abstract] Pathogens, such as bacteria, viruses, protozoa and fungi, generate molecules that provide them with a selective advantage, often at the expense of the host. These molecules, or virulence factors, enable pathogens to colonize the host through several mechanisms. Some molecules offer the pathogen an advantage through better adhesion to host tissues, or superior invasive capability. Some allow the pathogen to evade or suppress the host's immune system. Some molecules enable intracellular parasites to disable cytoprotective mechansims, by re-directing the host phagocytic vesicles. Many of these molecules are proteins that are exported to the cell's surface or are secreted. As unlikely as it seems, GAPDH appears to play a role as a virulence factor in a number of pathogenic organisms by the mechanisms just described. This highly conserved protein is found on the outer surface or as a secretory product of these organisms. The process by which pathogenic GAPDH, which has >40 % sequence identity to human GAPDH, is exported and attached to the outer surface of cells remains unknown. This chapter also presents a previously unpublished proposed docking sequence on GAPDH. There is also discussion of the potential of using the antigenic properties of pathogenic GAPDH for medical as well as for veterinary purposes. |
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