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Flashcards in complement pathway Deck (16):
1

what activates the 

classic complement pathway

antigen-antibody complexes

 

(IgG or IgM binds antigen and then C1 coimplement protein)

2

what activates the alternative pathway?

  • activated by molecules on the surface of microbes
  • spontaneous activation

DOES NOTrequire antibodies

 

 

 

3

lectin pathway in complement cascade

needs what to activate  it

Microbial surfaces (mannose)

Mannose-biniding lectin binds mannose on surface of microbes

4

what is the starting point of the CLASSIC PATHWAY

C1

C1 inhibitor inhibits (esterase inhibitor)  cleavage of C1 into active components

5

MAC 

membrane attack complex

is formed by

C5b

C6

C7

C8

C9

6

C3b

FUNCTION?

Opsonization

this causes phagocytosis of encapsulated bacteria

7

if a pt is def in C3b what infections are the suceptable to?

encapsulated organisms

8

C5a

function?

neutrophil chemotaxis!!!

9

what are the two most important opsonins 

C3b and IgG

10

C3a, C5a and C4a

stimulate?

Anaphylaxis

11

C3a

 stimulate what cells

Mast cells

Basophils

12

deficiency of C1 esterase inhibito

causes what disease?

hereditary angioedema

- due to unregulated activation of kallikrein --> inc bradykinin

classic findings: edema of skin (especially periorbital) + mucosal surface

CI: never give ACE inhibitor

 

13

Deficiency of C3 

can lead to?

recurrent pyogenic sinus infections and  respiratory tract infections.

(especially encapsulated bacteria) 

- strept pneumoniae, H. influ

and

**inc susecptibility to type III hypersensitivity rxn 

-especially ( glomerulonephritis) 

14

def of C5b, C6, C7, C8 or C9  (MAC)

cant form Membrance attack complex. 

this incresaed risk for?

Neisseria bacteremia!

( gonoccocal or meningococcal)

15

def in DAF (CD55)

.paraoxysmal nocturnal hemoglobinuria

occurs when RBCs are def in two surface molecules that help protect against the MAC:

-Glycoylphospnoinositol (GPI) which anchors decay accelerating factor (CD55) to plasma membrane

MAC- inhibitory protein (CD 59)

 

get chronic intravascular hemolysis-->

hemosiderinuria

- thrombosis (platelets get destroyed releasing prothrombotic contents) 

diagnosis - hams test (lysis rbc at low ph), flow cytometry - look for CD55/59. if not seen then they have it

TX - transfusion, warfarin, ECULIZUMAB.

 

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