[Control of over-activated innate immunity]

The basic reactions of innate immunity are reviewed. The mechanisms of innate immunity described are: phagocytosis, secretion and activity of cytokines, cytokine-dependent resistance of leukocytes to viral infections, the killing activity of NK cells independent on MHC, and killing by lectin-activated complement. Properly controlled, these mechanisms are responsible for maintaining homeostasis. Deficiency is frequently associated with the occurrence of infections or tumor diseases. On the other hand, over-activation is observed in autoimmunity, neurodegeneration, and inflammatory diseases. It is usually accompanied by elevated cytokine production, NO, oxidative stress, and the killing of cells. Therefore, the mechanisms which control the reactions of natural immunity are of importance for human and animal organisms. Natural mechanisms in human and animal organisms which mitigate these reactions are know. Among the mechanisms controlling innate immunity are cytokines (IL-10, TGFbeta), suppressors of cytokines signaling (SOCS), Tyro-3 receptors, and adenosine and adenosine phosphates. The possible participation of other mechanisms involved in controlling innate immunity are also considered.