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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, also known as the acquired immune system, or specific immune system is a subsystem of the immune system that is composed of specialized, systemic cells and processes that eliminate pathogens or prevent their growth. The acquired immune system is one of the two main immunity strategies found in vertebrates (the other ...
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 ...
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. Specifically, the fragment, bound to the major histocompatibility ...
The innate immune system is an alternate defense strategy and is the dominant immune system response found in plants, fungi, prokaryotes, and invertebrates (see Beyond vertebrates). [2] The major functions of the innate immune system are to: act as a physical and chemical barrier to infectious agents; via physical measures such as skin and ...
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]
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".
Cytotoxic T cells are powerful agents of cellular immunity. Cellular immunity, also known as cell-mediated immunity, is an immune response that does not rely on the production of antibodies. Rather, cell-mediated immunity is the activation of phagocytes, antigen-specific cytotoxic T-lymphocytes, and the release of various cytokines in response ...