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Immune Response Adaptive Immune Response

Immune Response

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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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Page 1: Immune Response

Immune Response

Adaptive Immune Response

Page 2: 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

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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

Page 8: Immune Response

Antigenic Determinants Certain parts of an entire antigen that are

immunogenic Antibodies and lymphocyte receptors bind to

them

Page 9: Immune Response

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

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Examples

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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

Page 14: Immune Response

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