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How do viruses trigger inflammation in body tissues?
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inflammation
The main function of complement proteins is to aid in the destruction of pathogens by piercing their outer membranes (cell lysis) or by making them more attractive to phagocytic cells such as macrophages (a process known as opsonization). Some complement components also promote inflammation by stimulating cells to release histamine and by attracting phagocytic cells to the site of infection.
Viruses trigger inflammation in body tissues primarily through two mechanisms: direct cellular destruction and the body's secondary immune response.12
- Direct Tissue Damage: Viruses are obligate parasites that must enter host cells to replicate. Many viruses cause inflammation by infecting and destroying these cells, which releases cellular debris and triggers an inflammatory response as the body attempts to clear the damage.342
- Secondary Immune Response: Often, the disease associated with a viral infection is caused by the host's own immune system rather than the virus itself. When the immune system detects viral proteins, it mounts a cellular immune response. Killer T cells identify and destroy virus-infected cells to prevent the spread of the pathogen. While this is a protective measure, the resulting death of vital cells—such as neurons, muscle cells, or liver cells—induces inflammation, which can inadvertently cause further tissue damage.1
Once triggered, the inflammatory response involves the release of chemical signals, such as cytokines, which increase blood flow and capillary permeability to bring phagocytic cells to the site of infection to eliminate the threat.45