Complement Flashcards

Complement Fixation Pathways

Question	Answer		Article
What are the names of the different pathways of the complement cascade?	Classical Alternative Mannose-binding Lectin		Link to Article
Which immunoglobulins can activate the classical pathway?	IgM IgG		Link to Article
What are the components of the C1 complex	C1q C1r C1s		Link to Article
Which two complexes bind to make the enzyme C3 convertase?	C2a C4b		Link to Article
What initiates the membrane attack complex (MAC)?	C3b		Link to Article
What functions do the C fragments C3a, C4a, C5a and C2b have?	Chemotactic for neutrophils Induces acute inflammation Increases vascular permeability Causes mast cell and basophil degranulation		Link to Article
What are efficient activators of the alternative pathway?	Gram-negative bacteria Yeasts Fungi		Link to Article
What are the main functions of the alternative pathway?	To coat bacteria with iC3b To induce an acute inflammatory response		Link to Article
What are lectins?	Proteins which bind carbohydrates		Link to Article
What does MASP stand for?	Mannose-binding lectin associated proteases		Link to Article

Complement Inhibitors

Question	Answer		Article
Which complement inhibitor exorts control over the classical pathway and how does it function?	Delay acclerating factor (DAF) Increases the degredation of C1 esterase		Link to Article
What do factors I and H do?	Breaks down C3b Controls positive feedback by inhibiting C3b¯Bb Prevents the complement cascade from running to exhaustion every time it is activated		Link to Article
Which complement inhibitor binds inflammatory immune complexes in the plasma, transporting them to the liver for phagocytosis?	Complement receptor 1 (CR1)		Link to Article
What does CD59 do?	Prevents cell lysis and pore formation It is a protective mechanism for cells		Link to Article

Functions of the Complement Cascade

Question	Answer		Article
What are the stages of opsonisation?	The complement system deposits a shell of protein on the bacterial cell surface, e.g. complement fragments Complement fragments released are chemotactic for phagocytes iC3b acts as a target for phagocytosis Phagocytes bind with the complement fragments destroying the bacteria		Link to Article
What role do complement fragments have to promote inflammation?	Smaller complement fragments attract granulocytes to the site of inflammation Smaller complement fragments stimulate the degranulation of granulocytes		Link to Article
By which process can C5-C9 directly kill pathogens?	Cell lysis		Link to Article

Originally funded by the RVC Jim Bee Award 2007