mannose binding lectin Flashcards
mannose binding lectins belongs to the class of
collectins in the c-type lectin superfamily
function of collectins
pattern recognition
manose binding lectin is instrumental
in innate immunity
mannose binding lectin role in the lectin pathway
as an opsonin
how does MBL start the lectin pathway?
MBL binds to carbohydrates found on the surface of many pathogens
examples of pathogens MBL binds to
yeasts- candida
viruses- HIV
Bacteria- salmonella
Parasite
MBL is completed with
MASPs
MASPs are
MBL-asoaited serine proteases
in order to activate the lectin complement system
when MBL binds to its target e.g. mannose on the surface of a bacterium, the MASP protein cleaves blood protein CD4 into C4a and C4b.
C4b
binds to the surface of the bacterium and initiates the formation of a C3- convertase
activation of C3-convertase
results in the creation of the membrane attack complex
the membrane attack complex
a structure which forms one the surface of pathogen cell membranes as a result of the hosts complement system
structure of the MAC
The membrane-attack complex (MAC) forms transmembrane channels. These channels disrupt the cell membrane of target cells, leading to cell lysis and death
MAC is composed of subunits
C5b, C6, C7, C8 and several C9 molecules
