IP 3 Immunology Definitions

alchemist04's version from 2018-12-22 00:34


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Immunity isthe ability to resist damage from foreign substances such as microorganisms, harmful chemicals, or cancer cells.
Innate immunity, or nonspecific immunity isa branch of the immune system that recognizes and destroys foreign substances with the same response to each exposure.
Adaptive Immunity, or specific immunity, isa branch of the immune system that recognizes and destroys foreign substances with faster and stronger responses each time the foreign substance is encountered.
Specificity isthe ability of adaptive immunity to recognize a particular substance.
Diversity, in relation to adaptive immunity, refers to theexistence of a large number of lymphocytes with different antigenic specificities.


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Memory isthe ability of adaptive immunity to remember previous encounters with a particular substance, and as a result, to respond faster, stronger, and longer.
Antigens aresubstances that stimulate adaptive immunity, and are divided into two groups: foreign antigens and self-antigens.
Foreign antigens arenot produced by the body, but are introduced from outside. Examples include: pollen, animal dander, foods, drugs, and components of bacteria, viruses, and other microorganisms.
Self-antigens aremolecules the body produces that stimulate an adaptive immune response. The response can be beneficial or harmful, such as recognition of tumor antigens to enable tumor destruction, or the stimulation of unwanted tissue destruction in autoimmune diseases, respectively.
Antibodies areproteins that are produced by plasma cells (differentiated B cells) in response to an antigen. They are also referred to as immunoglobulins (Ig) because they are globulin proteins involved in immunity.


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Opsonization isthe ability to render invading pathogens more susceptible to phagocytosis (i.e. through the binding of antibody or complement proteins to the surface membrane).
Complement is agroup of 20 proteins that comprise 10% of the plasma globulin. When activated in the complement cascade, formation of a membrane attack complex (MAC) that mediates cell lysis, opsonization of bacterial cells, and/or attraction of immune cells to site(s) of infection can occur.
Major Histocompatibility Complex (MHC) molecules areglycoproteins expressed on the surface of most of the body’s cells. MHC molecules display antigens produced or processed inside the cell on the cell’s surface to be recognized by immune cells.
Lymph isthe clear or yellowish fluid found in lymphatic vessels that is derived from excess interstital fluid from blood vessel capillary exchange.
Costimulator isa molecule on the surface of an antigen-presenting cell that provides a second signal required for activation of naive T cells in addition to the first signal, the antigen.