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Flashcards in Complement-L7 Deck (22):
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Complement

Term for a complex system of sequentially interacting serum proteins. Activation of the complement cascade results in cell lysis, increased phagocytosis, increased vascular permeability, enhanced leukocyte chemotaxis and functional stimulation of macrophages.

1

End result of complement pathways

Cleavage of C3 eventually leading to cell lysis.

2

Membrane attack complex

Components C5-C9, lyses the target cell

3

C3a

Recruits phagocyte

4

C3b

Tags bacterium for destruction

5

Alternative pathway

-Pathogen surface creates local environment conducive to complement activation
-First to act

6

Classical pathway

-C reactive protein or antibody binds to specific antigen on pathogen surface
-IgM binds antigen on a pathogen surface
-Third to act

7

Consequences of C3 being cleaved to C3a and C3b

-Recruitment of inflammatory cells
-Opsonization of pathogens, facilitating uptake and killing by phagocytes
-Perforation of pathogen cell membranes
-Death of pathogen

8

CR1

-Ligand:C3b, C4b
-Stimulates phagocytosis and erythrocyte transport of immune complexes

9

CR2

-Part of B cell co-receptor

10

CR3

-Stimulates phagocytosis

11

CR4

-Stimulates phagocytosis

12

Anaphylatoxin

-C3a, C5a
-Histamine release for mast cells
-Increase vascular permeability

13

Chemotaxis

-C5a
-Attract polymophonuclear leukocytes and macrophages

14

Opsonization

-C3b
-Increased phagocytosis of particles by granulocytes and macrophages

15

C1, C2, C4 deficiency

-Immune complex disease

16

C3 deficiency

Susceptibility to encapsulated bacteria

17

C5-C9 deficiency

-Susceptibility to Neisseria

18

Factor D, properdin deficiency

-Susceptibility to encapsulated bacteria and Neisseria but no immune complex disease

19

Factor I deficiency

-Susceptibility to encapsulated bacteria

20

DAF, CD59 deficiency

-Auto-immune like conditions including paroxysmal nocturnal hemogobinuria

21

C1INH deficiency

-Hereditary angioedema (HAE)