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In the first line of defense, inhaled bacteria are trapped by mucus and are swept toward the pharynx and are swallowed. [1] Bacteria which penetrate the mucous layer are dealt with a second line of defense which includes antimicrobial peptides that are secreted by the surface epithelium of the respiratory tract which kill many strains of ...
An immune response is a physiological reaction which occurs within an organism in the context of inflammation for the purpose of defending against exogenous factors. These include a wide variety of different toxins, viruses, intra- and extracellular bacteria, protozoa, helminths, and fungi which could cause serious problems to the health of the host organism if not cleared from the body.
Inflammation is one of the first responses of the immune system to infection or irritation. Inflammation is stimulated by chemical factors released by injured cells. It establishes a physical barrier against the spread of infection and promotes healing of any damaged tissue following pathogen clearance. [5]
A scanning electron microscope image of a single neutrophil (yellow/right), engulfing anthrax bacteria (orange/left) – scale bar is 5 μm (false color). The immune system is a network of biological systems that protects an organism from diseases.
Complement proteins are proteins that play a role in the non-specific immune responses alongside these non-specific immune cells to make up the first line of immune defense. [4] The non-specific immune response is an immediate antigen-independent response, however it is not antigen-specific. Non-specific immunity results in no immunologic memory.
Once a DAMP is released from the cell, it promotes a noninfectious inflammatory response by binding to a pattern recognition receptor (PRR). [4] Inflammation is a key aspect of the innate immune response; it is used to help mitigate future damage to the organism by removing harmful invaders from the affected area and start the healing process. [5]
Inflammation is a generic response, and therefore is considered a mechanism of innate immunity, whereas adaptive immunity is specific to each pathogen. [2] Inflammation is a protective response involving immune cells, blood vessels, and molecular mediators. The function of inflammation is to eliminate the initial cause of cell injury, clear out ...
Among the PGs, anti-inflammatory PGE2 and pro-inflammatory PGD2 increase the most after activation, with PGE2 increasing expression of IL-10 and inhibiting production of TNFs via the COX-2 pathway. [35] [36] Neutrophils are among the first immune cells recruited by macrophages to exit the blood via extravasation and arrive at the infection site ...