Flashcards in Extension of Ppt 6 Complement Deck (37):
What is C3b used for?
opsonization of microbes
who recognizes C3b in phagocytes?
What other complement molecule is recognized with C1 receptor in phagocytes?
what other complement molecule works as an opsonin?
what does the MAC (membrane attack complex) do to microbes?
it creates pores in their membranes
what are C3a, C4a and C5a?
what do anaphylatoxins do?
they cause smooth muscle contraction and histamine release from mast cells
what complement pathway is activated by C3b?
the alternate pathway
how do you start the classical pathway of complement? (binding what?)
you bind C1 to microbe
what happens with complement if you bind a lectin to a microbe?
you start the Mannose binding lectin pathway
what do all pathways have in common?
they all create the MAC complex and all lead to C3b
what happens to C3 in plasma during the alternative pathway?
C3 gets hydrolized and forms C3b that binds to antigen
In alternative pathway, fluid C3b will do what? by binding to whom?
bind to antigen, especially to Factor Bb
When C3b binds to Factor Bb in the alternative pathway, what will be created?
what does the C3 convertase in alternative pathway do?
cleave more C3 to C3b
In the alternative pathway, more C3b created will do what?
bind more and more to the microbe surface
in the alternative pathway, when many C3b are bound to the Factor Bb, what is formed?
in the alternative pathway, what will C5 convertase do?
it will cleave C5 into C5b
what does C5b initiate in the alternative pathway of complement?
it begins the late phase of complement
how is the classical pathway of complement initiated?
by binding of C1 to the antibodies bound on microbe
in the classical pathway of complement, what binds to the C1 protein? what happens after it binds?
C4 binds to C1 and C1 cleaves it to C4b
In the classical pathway of complement, what will C4b do after it is cleaved by C1?
C4b will bind to microbe surface
In the classical pathway of complement, what will happens after C4b binds to microbe and to the antibodies bound to microbe?
C2 binds to C4b and gets cleaved forming the complex C4b + C2a
In the classical pathway of complement, what is another name for the complex C4b + C2a?
In the classical pathway of complement, what will the C4b + C2a complex do in the microbial surface?
it will cleave C3 into C3b
In the classical pathway of complement, what will happen to the C3b produced by the C3 convertase (C4b+C2a complex)?
C3b binds to microbe surface and to the C3 convertase
In the classical pathway of complement, when the C3b binds to C3 convertase, what gets formed?
the C5 convertase
when does the late phase of compliment start?
when C5 convertase is formed
what does the late phase involve?
cell lysis (MAC) and inflammation (C5a)
what does DAF do to the alternate pathway of complement?
it removes the Factor Bb off the C3 convertase
what does DAF do to the classical pathway of complement?
it will remove C4b off the C3 convertase
what does the C1 inhibitor do?
blocks attachment of C1, so classical pathway of complement cant proceed
What does C1R do in the alternate pathway of complement?
it removes Factor Bb preventing the formation of C3 convertase
What does C1R do in the classical pathway of complement?
it removes C4b preventing formation of C3 convertase
deficiency of C9 leads to profound infection by who?
C2 and C4 deficiency leads to infections resembling what disease?