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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.
The adaptive immune system evolved in early vertebrates and allows for a stronger immune response as well as immunological memory, where each pathogen is "remembered" by a signature antigen. [55] The adaptive immune response is antigen-specific and requires the recognition of specific "non-self" antigens during a process called antigen ...
T cells contribute to immune defenses in two major ways: some direct and regulate immune responses; others directly attack infected or cancerous cells. [7] CD4+ lymphocytes, also called "helper" T cells, are immune response mediators, and play an important role in establishing and maximizing the capabilities of the acquired immune response. [3]
Antigen presentation is a vital immune process that is essential for T cell immune response triggering. Because T cells recognize only fragmented antigens displayed on cell surfaces , antigen processing must occur before the antigen fragment can be recognized by a T-cell receptor .
The immune system has innate and adaptive components. Innate immunity is present in all metazoans, [1] immune responses: inflammatory responses and phagocytosis. [2] The adaptive component, on the other hand, involves more advanced lymphatic cells that can distinguish between specific "non-self" substances in the presence of "self".
Immunology is a branch of biology and medicine [1] that covers the study of immune systems [2] in all organisms.. Immunology charts, measures, and contextualizes the physiological functioning of the immune system in states of both health and diseases; malfunctions of the immune system in immunological disorders (such as autoimmune diseases, hypersensitivities, [3] immune deficiency, [4] and ...
However, strictly speaking, immunogenicity refers to the ability of an antigen to induce an adaptive immune response. Thus an antigen might bind specifically to a T or B cell receptor, but not induce an adaptive immune response. If the antigen does induce a response, it is an 'immunogenic antigen', which is referred to as an immunogen.
The history of phagocytosis represents the scientific establishment of immunology as the process is the first immune response mechanism discovered and understood as such. [1] [2] The earliest definitive account of cell eating was given by Swiss scientist Albert von Kölliker in 1849. [3]