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cytokines
- small secreted proteins
- mediate and regulate immune response
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interferons (IFN)
- produced in response to viral infection (INF-a, INF-b)
- produced upon activation of the immune respone (INF-gamma)
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lymphokines
cytokines made by lymphocytes
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chemokines
- cytokines with chemotactic activities
- attracks leukocytes to infection sites
- associated with inflammatory response
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interleukins (IL)
cytokines made by one leukocyte which act on othr leukocytes
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antigen presenting cells (APC)
displays proteins of a foreign cell on its surface (epitope) to alarm and activate other immune cells
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different types of leukocytes
- neutrophils
- eosinophils
- basophils
- monocytes (dendritic cells, macrophages)
- lymphocytes (B and T cells and Natural Killer cells)
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neutrophil
phagocyte
known as a polymorphonuclear leukocytes or "seg"
migrates from the from blood to infection site in response to chemotactic factors
recognizes and binds to immunoglobulin and complement coated via receptors on its surface
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eosinophil
- phagocyte
- relases toxic contents of granules to burn holes in cells
- primary role: kill parasites
- minor role: against bacteria
- accumulate in the face of an allergic reaction
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Basophil
- not a phagocyte
- contain heparin and larg amount of histamine
- play a role in Type 1 hypersensitivity (allergic) reaction
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moncytes
- phagocytes that circulate in the blood
- develop into (macrophages, dendritic cells)
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macrophage
- phagocytosis
- antigen presentation to T-cells
- bind to immunoglobulin via cell surface receptor for IgG
- bind to complements
- secrete cytokins
- activated by T cells and cytokines
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dendritic cell
- phagocytosis
- most efficient antigen presenters
- determines nature of T-cell response
- secrete cytokines
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lymphocytes
- natural killer cells
- circulate in blood and lymp
- no specific surface markers
- B or T cells
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B cells
- indruce antibody production
- presents Af to T-cells
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T cells
- contain surface receptors (TCR) that recognize antigen on the surface of other cells
- basis of cell-mediated immunity
- CD8+ and CD4+
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CD8+ T cells
- cytotoxic cells
- recognize Ag presented by APC
- kell cells expressing appropriate Ag
- release lymphotoxins which cause cell lysis
- down regulate activity of other cells
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CD4+
- helper cells
- coordinate immune response by communitcating with other cells
- secrete cytokines - stimulate cytotoxic T cells and B cells to grow and differentiate
- activate macrophages
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Memory T cells
recognize and respond to an antigen once it's inhaved and been repelled
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Memory B cells
recognize and produce antibody to an antigen once it has invaded and been repelled
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Immunoglobulin (Ig)
- glycoprotien
- produced in response to a specific antigen
- known as antibodies - major role in humoral immunity
- produced by plasma cells
- may act as:
- antigen receptors on the surface of B cells
- antibodies that inactivate antigens
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IgG
- most common
- activates complement
- binds to phagocytic cells surfaces
- transferred via the placenta
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IgM
- fist Ab produced in response to antigen
- pentamic mlcl
- receptor on B cell surface
- most efficeint Ab for activating complement
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IgA
- exists as monomer, dimer, trimer, and multimer
- concentrates in body fluids to guard agains entrances to body
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IgE
- protects agains parasites
- binds to mast cell surfaces adn elicits allergic response
- responsible for anaphylactic hypersensitiveity reactions
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IgD
acts as a B cell receptor to intiate B cell response
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