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Immune Response. Adaptive Immune Response. Adaptive Immune. Adaptive or Acquired Immune Response. Protects against infectious agents and abnormal body cells Amplifies the inflammatory response Activates complement. Adaptive Defenses. Adaptive immune response Is systemic Is specific - PowerPoint PPT Presentation
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Immune Response
Adaptive Immune Response
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Adaptive ImmuneAdaptive Immune
Response
Humoral Immunity
B cells
Cellular Immunity
T cells
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Adaptive or Acquired Immune Response
Protects against infectious agents and abnormal body cells
Amplifies the inflammatory response
Activates complement
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Adaptive Defenses Adaptive immune response
Is systemic Is specific Has memory
Two separate overlapping arms1. Humoral (antibody-mediated) immunity2. Cellular (cell-mediated) immunity
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Acquired or Adaptive Immune ResponseThere are two major branches of the adaptive immune response
Humoral Antibody- mediated
immune response Mediated by B-
lymphocytes
Cellular Cell-mediated
immune response Involves the
production of cytotoxic T- lymphocytes, activated macrophages, activated NK cells, and cytokines in response to an antigen
Mediated by T-lymphocytes
Antigens Substances that can mobilize the adaptive
defenses and provoke an immune response Most are large, complex molecules not
normally found in the body (nonself)
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Acquired or Adaptive Immune Response During adaptive immunity:
Bone marrow & thymus (primary lymphoid tissues) produce B cells and T cells, respectively
Immature T cells migrate to thymus and become competent T cells
B cells and T cells recirculate through spleen and lymph nodes (secondary lymphoid tissues)
Antigen (Ag) presenting cells (APC) pick up antigen and migrate to secondary lymphoid tissues & interact with T cells and B cells
Antigenic Determinants Certain parts of an entire antigen that are
immunogenic Antibodies and lymphocyte receptors bind to
them
Antigenic Determinants Most naturally occurring antigens have
numerous antigenic determinants that Mobilize several different lymphocyte populations Form different kinds of antibodies against it
Large, chemically simple molecules (e.g., plastics) have little or no immunogenicity
Examples
“Simple” molecules Stainless steel plastics
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Examples
Cells of the Adaptive Immune System Two types of lymphocytes
B lymphocytes (B cells)—humoral immunity T lymphocytes (T cells)—cell-mediated immunity
Antigen-presenting cells (APCs) Do not respond to specific antigens Play essential auxiliary roles in immunity
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Antigen Processing and Presentation In order to generate adaptive immunity, as
well as long lasting memory, Ag should be recognized by T and B cells
Lymphocytes make up to a billion different types of antigen receptors
Memory usually improves upon repeated exposure to a given infection
Antigen-Presenting Cells (APCs) Engulf antigens Present fragments of antigens to be
recognized by T cells Major types
Dendritic cells in connective tissues and epidermis
Macrophages in connective tissues and lymphoid organs
B cells
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Differences in Innate and Adaptive Immunity The innate and adaptive immune responses both function
to protect against invading organisms, but they differ in a number of ways
(1) The innate immune system is constitutively present and reacts immediately to infection. The adaptive immune response to an invading organism takes some time to develop
(2) The innate immune system is not specific in its response and reacts equally well to a variety of organisms, whereas the adaptive immune system is antigen-specific and reacts only with the organism that induced the response
(3) The adaptive immune system exhibits immunological memory. It "remembers" that it has encountered an invading organism (antigen) and reacts more rapidly on subsequent exposure to the same organism. The innate immune system does not possess a memory.
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Acquired ImmunityType of Immunity How acquired by Host Examples
Active Immunity Occurs when an individual is exposed to an infectious agent or one of its products (antigens)
Active Natural Immunity: Antibodies are produced by the host in response to the infectious agent itself (e.g. Recovery from disease)
Active Artificial Immunity: Occurs through vaccination with a form of the disease microorganism. It may be dead, attenuated (weakened), or altered so that it will not produce the disease but will cause the body to produce antibodies.
Passive Immunity
As a result of acquisition of antibodies which have been produced by another animal (by active means) or derived from cells grown in tissue culture
Passive Natural Immunity: Transfer of antibodies from a mother to her baby through the placenta; Transfer of antibodies from mother to infant in milk if nursing.
Passive Artificial Immunity: Acquired through inoculation with antibodies. Injection of immune serum from an individual previously immunized or recovered from disease