Immune system, innate

A cascade of proteins of the immune response that can be triggered by antigen-antibody complexes and by the innate immune system (e.g. exposure to microbial polysaccharides) to raise the immune response. Complement proteins can detect and bind to foreign material or immune complexes and label them for phagocytosis. They can also cause inflammation by directly degranulating mast cells and releasing chemokines to recruit other immune cells into the affected area. 

Humoral immunity depends on soluble, noncellular effector mechanisms of the immune system. These include defensins and complement components (proteins of the innate immune system) and antibodies (products of the adaptive immune system). They are capable of reacting with foreign substances (e.g., bacteria and viruses) to produce detoxification and elimination. 

While cells of the innate immune system can combat invading microbes autonomously, their effector mechanisms are also used and greatly enforced by the... 

Pattern recognition receptors (PRRs) are receptors expressed by cells from the innate immune system... 

The innate immune system is found across all organisms and is thought to have originated before the split into animal and plant kingdoms. It is the body s primaiy response to attack. Receptors used in this system must be capable of recognising abroad range of pathogens. This... 

Ulevitch RJ (2004) Therapeutics targeting the innate immune system. Nat Rev Immunol 4(7) 512—520... 

Martinelli, C. 8c Reichhart, J.-M. (2005). Evolution and integration of innate immune systems from fruit flies to man lessons and questions. /. Endotoxin Res., 11, 243-8. 

Ulevitch, R.J. and Tobias, P.S. (1999) Recognition of gram-negative bacteria and endotoxin by the innate immune system. Current Opinion in Immunology 11, 19-22. 

In biochemical systems, acid-base and redox reactions are essential. Electron transfer plays an obvious, crucial role in photosynthesis, and redox reactions are central to the response to oxidative stress, and to the innate immune system and inflammatory response. Acid-base and proton transfer reactions are a part of most enzyme mechanisms, and are also closely linked to protein folding and stability. Proton and electron transfer are often coupled, as in almost all the steps of the mitochondrial respiratory chain. 

Several bacteria in the natural gut flora or non-pathogenic bacteria which can colonise the gut have been shown to have preventive or even therapeutic effects on pathogens. Most commonly used and studied are bifidobacteria and lactobacilli (see Fig. 13.2) they have been shown to stimulate the innate immune system to produce cytokines, antimicrobial compounds and other metabolites affecting either the host and/or enteric bacteria (Aattouri et al., 2001 Xuan et al., 2001 Kralik et al, 2004 Scharek et al., 2005 Tannock, 2005 Davis et al., 2006). 

In contrast to adaptive immune function, fewer studies have examined effects of TCDD on the innate immune system. Furthermore, of the limited data available, much of it is inconsistent. For example, natural killer (NK) cell activity has been reported to be unaffected,80,93 diminished,94 and increased95 following exposure to TCDD. Although a thorough assessment of AhR expression in all innate cell lineages has not been conducted, neutrophils and macrophages express the AhR,8,96 and neutrophils are affected... 

Inflammation is the normal host response to infection or injury that mediates immune elimination of pathogens and tissue repair. Inflammatory processes include increased production of cytokines, chemokines, nitric oxide, and eicosanoids by the innate immune system in conjunction with altered leukocyte homing, all of which greatly impact acquired immunity. Aberrant inflammatory responses evoke both acute injury such... 

Kurtz, J., Specific memory within innate immune systems, Trends Immunol. 26, 186, 2005. 

Rodent and human immunology has served to guide our understanding of the mammalian immune system, where the highly conserved innate immune system, and the more complex acquired or adaptive immune system, interact to protect the host from infection. 

A relatively sharp distinction must be drawn between what are termed the innate and the adaptive immunities (Ml). When an organism infects the body, the defense systems already in place may well be sufficient to prevent replication and spread of the infectious agent, thereby preventing the development of disease. These established mechanisms constitute the innate immune system. However, should innate immunity be insufficient to prevent the invasion by the infectious agent, the adaptive immune system then comes into action, although it takes time... 

Innate immune system Adaptive immune system... 

Thus, these data indicate that similar to immature DCs, alternatively activated MO can induce immunosuppressive Tregs and that in return these Tregs are potent suppressors of MO maturation (fig. 2). Since MO bridge the innate and the acquired immune system, Tregs are able to gain influence on the innate immune system by interactions with MO. 

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