Innate Immunity part II

Innate Immunity part II

1. Recognition mechanism

   • Toll receptors
     • Neutrophils and Macrophage have NONCLONALS (germ-line encoded receptors) that recognise the foreign invasion
     • There are a lot of Toll receptors that bind to specific mechanisms, this can activate cytokine genes and alert the entire immune system
     • Toll-like receptors are used to recognise PAMPs (pathogenic associated molecular patterns) and results in the phagoctysosis of the pathogen
   • Interferon
     • Reacts specifically in response to an invasion by viruses
     • The infected cell produce proteins that are sent to neighbouring cells to warn them of the impending doom that will be the attack of the virus
   • Opsonins
     • A specific opsonins is antibodies
     • They attach and flag the antigen and anything that is flagged will be phagocyted
   • Compliment
     • Is made up of a large number of distinct plasma proteins that react with one another to opsonize pathogens and induce a series of inflammatory responses that help to fight infection
     • Results in phagocytosis

2. Effector mechanism

   • Compliment activation (labelling and lysis)
     • Immune adherence (mast cells, neutrophylls and macrophages)
     • Anaphylatoxins (attract mast cells, neutrophylls and macrophages)
     • Membrane lysis
       • via the numerous amount of cells are able to punch a hole through the pathogens membrane
   • Natural Killer cells
     • These cells are able to release their preformed cytotoxic granules and kill cells that are infected by viruses and by some intracellular bacteria
     • Powerful producers of cytokines
     • Continuously polices the bodies cells 24/7

3. Recruitment mechanism

   • Cells entering the tissue
     • Neutrophils
     • Eosinophils
     • Basophils
     • Monocytes
     • B - lymphocytes
     • T - lymphocytes
   • Plasma entering the tissue
     • Complement proteins
     • Antibodies
     • Clotting factors and platelets
     • Lysozyme
     • Beta-defensins
     • Transferring
     • Nutrieints
   • Killing the invading pathogen
     • Complement proteins and Beta-defensins = attachment, WBC chemotaxis and cell lysis
     • Antibodies = opsonisation leads to cell lysis
     • Metalloprotease and lysozyme = breaks down microorganisms
     • Free Radicals = oxidases reduce oxygen to superoxide (very toxic to pathogen)
   • Initial recruitment
     • Following infection mast cells release vasodilators which enables vascular endothelial cell to increase their expression of adhesion molecules
     • This increases capillary permeability allowing plasma and leukocytes to leave the bloodstream and enter the tissue
     • Molecules called selectins cause the circulating leukocytes to slow their flow and roll along the inner blood vessel wall
     • The chemokines (IL-8) are held on the inner surface of the endothelial cells where they interact with chemokine receptors on the surface of the rolling leukocytes
     • This triggers the activation of molecules called integrins on the surface of the leukocytes that are activated by chemokines enabling the slowly rolling leukocytes to strongly bind to adhesion molecules on the inner surface of the vascular endothelial cells
   • Compartmentalised

Images and files in the map