The Complement System Flashcards
Complement consists of a group of __________ proteins circulating in inactive form.
serum
Once activated, the catalytic cascade can lead to multiple possible outcomes. Name 3 discussed in class.
- Directly lyse target cell membrane
- Chemotaxis
- Opsonization to enhance phagocytosis
What are the three pathways of complement activation?
- Classical
- Lectin
- Alternative
CR1 is expressed on ________________ and ________________.
leukocytes and erythrocytes
C3aR and C5aR are expressed on __________________.
granulocytes
C3aR and C5aR stimulate the release of ________________ cytokines. The “a” in their name refers to ________________.
pro-inflammatory; anaphylatoxins
Which receptor is involved in removal of immune complexes?
CR1
The classical pathway begins with the formation of ________________________.
Antigen-antibody complexes
The lectin pathway is initiated when ______________ proteins recognize ______________ ______.
soluble; microbial Ags
The alternative pathway is initiated in __________ ways.
three
Which pathway is initiated by IgM or IgG binding to a multivalent antigen?
classical
Small amounts of _____ are always being cleaved.
C3
In the _____________ pathway, MBL binds to microbial surfaces and serve as a docking site for MBL associated serine proteases (MASPs).
lectin
MASPs cleave _____ and ______ to form the _________________.
C2; C4; C3 convertase
The planar form of IgM has many more C1q binding sites than the staple form of IgM. T or F?
FALSE; the opposite is true
Monomeric IgG has how many binding sites for C1q per molecule?
one; it is therefore less efficient at activating complement than IgM
The three complement pathways converge at the formation of the ___ ______________.
C5 convertase
C5 initiates the generation of what system?
MAC - membrane attack complex
The membrane attack complex is the result of ______________________________________.
the deposition of C proteins
C protein deposition results in a ______ structure, which disrupts ____________ integrity, resulting in ________ __________.
pore; osmotic; cell death
