L9:Complement system and activation Flashcards
where are compliment serum proteins formed ?
liver
which pathway is important for adaptive immunity ?
classical pathway
what pathways are important for innate immunity ?
alternative and lecin pathways
what are the functions of compliment pathways ?
cell lysis by action of Major attack complex
opsonization of bacteria
generation of inflammatory mediators
what is the central molecule of all pathways ?
C3b
how is the classical pathway activated ?
antibody-antigen complex
c3 convertase in classical pathway is comprised of ?
C4b2b
what does C3a do?
activates mast cells causing rleases of vasoactive mediators like histamine
what does c5 convertase consist of ?
C4b,2b,3b
what does C5a do?
it is a pro-inflammatory anaphyltoxin and a chemotaxin
what is the major attack complex ?
C5b,6,7,8,9
how is the alternative pathway activated ?
there is NO antigen-antibody complex in the alternative pathway . instead , the pathway is activated when c3(h20) binds with B factor which has been cleaved by protease and factor D.
It is activated when C3b binds to any activator or microbial surface
how is factor b cleaved in the alternative pathway ?
by protease and factor D
how is the lecin pathway activated ?
when MBL or MBP bind to surface bearing mannose or mannon , which activates MBL associated serine proteases which in turn activates c4 and c2 to form c3 convertase
which pathway doesnt have c2 and c4?
alternative pathway
