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11 Cards in this Set
- Front
- Back
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Innate immune system
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- antigen independent
- no time lag - relatively non specific - no immunologic memory - physical barriers (skin, gut villi, lung cilia) - soluble factors include protein/non protein secretions - cells = phagocytes, natural killer cells, mast cells |
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Active immune system
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- antigen dependent
- has a lag period - antigen specific - memory cells (faster secondary response) - no physical barriers - soluble factors are immunoglobulins/antibodies - cells = T and B cells |
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Innate - Phagocytes (types)
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- Macrophages: mature from monocytes, adhere to surfaces and activate cytokines, take part in phagocytosis
- Neutrophils: short lived cells that are abundant in the blood and only enter tissue in response to inflammation + tissue damage. involved in phagocytosis, contain nucleus, cytoplasm and granules |
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Innate - Phagocytes (what they respond to(SOS signals))
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- LPS (gram -ve) or teichoic acid (gram +ve)
- mannose and other sugar residues - N-formyl methionine - bacterial heat shock proteins - clotting system peptides - complement products - proinflammatory cytokines/chemokines |
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Innate - Phagocytes (how they respond)
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- vascular adherence
- diapedesis (extravasation) - chemotaxis - activation - phagocytosis + killing |
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Innate - Phagocytes (oxygen independent killing)
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- phagosomal compartment containing bacteria fuses with lysosomes which release digestive enzymes into the vacuole and destroy the bacterium
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Innate - Phagocytes (oxygen dependent killing)
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- Reactive oxygen: binding bacteria in vacuole increases O2 uptake known as a respiratory burst, superoxide is formed which can be reduced to OH radicals or H2O2, which act as oxidising agents and damage cell structures (dna, membranes etc)
- Reactive nitrogen: activation of phagocyte leads to induction of nitric oxides synthase which produces high levels of NO and other reactive nitrogen species that act as microbicidal agents |
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Innate - Basophiles/Mast cells
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- basophiles: in the blood and mast cells in the tissue both share similar properties
- contain cytoplasmic granules which stimulate inflammation - degranulation is induced by trauma, toxins, antibodies etc and causes release of histamine, anticoagulants, leukotrieres and cytokines |
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Innate - Natural killer cells
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- kill infected or malignant cells
- on contact with an infected cell they release toxic granules which punch holes into the cell membrane causing it to burst by cell lysis - release high levels of cytokines |
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Active - Humoral/antibody response
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- B cells produce antibodies (immunoglobulins) these mark infected cells for destruction by phagocytosis by binding to antigens on microbe surface (specific)
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Active - Cell mediated response
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- T helper cells (CD4+) can be Th1 (produce cytokines that activate macrophages to increase there activity) or Th2 (activate B cells to produce antibodies)
- T killer cells (CD8+) recognise antibodies on infected cell, a lethal hit is given to the infected cell by the release of perforin which creates pores in the membrane and causes cell lysis |
