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Non-specific immunity, or innate immunity, is the immune system with which you were born, made up of phagocytes and barriers. Phagocytosis , derived from the Greek words phagein , meaning to eat, kytos or cell, and “osis” meaning process, was first described by Élie Metchnikoff , who won the Nobel Prize 100 years ago.
Some products of the coagulation system can contribute to non-specific defenses via their ability to increase vascular permeability and act as chemotactic agents for phagocytic cells. In addition, some of the products of the coagulation system are directly antimicrobial .
Phagocytes occur in many species; some amoebae behave like macrophage phagocytes, which suggests that phagocytes appeared early in the evolution of life. [ 6 ] Phagocytes of humans and other animals are called "professional" or "non-professional" depending on how effective they are at phagocytosis . [ 7 ]
Phagocytosis is one main mechanisms of the innate immune defense. It is one of the first processes responding to infection, and is also one of the initiating branches of an adaptive immune response. Although most cells are capable of phagocytosis, some cell types perform it as part of their main function. These are called 'professional phagocytes.'
Innate immune defenses are non-specific, meaning these systems respond to pathogens in a generic way. [19] This system does not confer long-lasting immunity against a pathogen. The innate immune system is the dominant system of host defense in most organisms, [2] and the only one in plants. [20]
The mononuclear phagocyte system is part of both humoral and cell-mediated immunity. The mononuclear phagocyte system has an important role in defense against microorganisms, including mycobacteria, fungi, bacteria, protozoa, and viruses. Macrophages remove senescent erythrocytes, leukocytes, and megakaryocytes by phagocytosis and digestion.
Cell-mediated immunity is directed primarily at microbes that survive in phagocytes and microbes that infect non-phagocytic cells. It is most effective in removing virus-infected cells, but also participates in defending against fungi, protozoans, cancers, and intracellular bacteria.
The second group is the non-phagocytic types that are distributed near regenerative fibers. These peak between two and four days and remain elevated for several days while muscle tissue is rebuilding. [60] The first subpopulation has no direct benefit to repairing muscle, while the second non-phagocytic group does.