Flashcards
Complement
Flashcards do conjunto (19)
- 1C5a acts through a GPCR on...Endothelial cells
Mast cells
Smooth muscle cells
Phagocytes - 2C5a causesActivation
Contraction
Chemotaxis - 3CR1 is expressed onRBCs
Monocytes
Macrophages
B cells
PMNs
FDCs - 4CR2 is expressed onB cells
FDCs - 5CR3 is expressed onMonocytes
Macrophages
PMNs - 6CR4 is expressed onMonocytes
Macrophages
PMNs
Dendritic cells - 7Function of the small molecules of complementAct independently as diffusible signals to promote an inflammatory response by recruiting leukocytes to the site of infection
- 8How to activate classical complementAntibodies bound to the surface of a pathogen
- 9How to activate lectin complementMannose-binding lectin is a secreted PRR that initiates the lectin pathway when it recognises bacterial or fungal glycolipids and glycoproteins bearing terminal mannose and fucose sugars in a particular spatial conformation
- 10How to activate alternative complementMolecules on the surface of pathogens will often directly activate the alternative pathway
- 11Sialic acidCarbohydrate moiety which is a common constituent of cell surface glycoproteins and glycolipids which is used by the host to prevent complement reactions proceeding on their surface
- 12Sialic acid in pathogensNeisseria gonorrhoeae coats themselves with a layer of sialic acid to effectively hide from the complement system
- 13Methods of complement inactivation (to ensure no host cell damage)Inhibitor proteins in the blood or on membranes bind or cleave the complement components after they have been activated by proteolytic cleavage
Many complement proteins are unstable so unless they bind the next protein or a nearby membrane they are inactivated - 14Classical complement activationIgM binds to its antigen through its five antigen biding domains generating a major structural change affecting the whole molecule causing it to transition from a planar to a staple conformation. These events expose complement binding sites in the Fc regions of each of the 5 subunits that initiate the process of complement activation
- 15IgMLarge pentameric molecule
Most efficient activator of classical complement - 16The alternative pathway functions in two interlinked ways...1. An efficient amplification loop to drive further complement activation whatever the initiating trigger
2. An always-on pathogen sensor ready to attack foreign surfaces - 17ProperdinBinds and stabilizes AP convertases, reducing their inherent tendency to fall apart ("decay") and increasing markedly their capacity to perpetuate activation
- 18Lectin pathway activationOnly differs to the CP in the initiation step.
C1 complex is replaced by a structurally similar multimolecular complex, comprising a C1q-like recognition complex, either mannan-binding lectin (MBL) or ficolin, and MBL-associated serine protease-2 (MASP-2) that provides enzymatic activity. The recognition unit binds carbohydrate epitopes which are abundant in the cell walls of diverse pathogens - 19Host cell defence against C3b bindingC1 inhibitor dissociated C1r and C1s from the active C1 complex
DAF, C4BP and CR1 displace C2b from C4b2b. C4b bounf by C4Bp, MCP or CR1 is cleaved by a soluble protease to inactive forms C4d and C4c
Express CD59 to prevent MAC assembly
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- Descrição
- FHS Part I Immunology and Microbiology (Innate Immunity) FlashCards sobre Complement, criado por Eleanor Smith em 18-12-2019.
- Criado por
- Eleanor Smith
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