Complement

Question 1

Classical pathway order

Answer 1

1r/q/s, 4, 2, 3, 5, 6/7/8/9

• C6,7,8 and 9 bind to the activated C5, forming the membrane attack complex
• C 8 is the one that first inserts itself into the membrane
• C9 polymerizes and forms a pore on the membrane surface
• creates lesions which kill the cell via a inrush of fluids

Question 2

opsinization and complement

Answer 2

coating of organisms with antibody and C3b so that they are more easily phagocytosed by neutrophils and macrophages (can do it alone but is much slower)

Question 3

chemotaxis in completment

Answer 3

• C3a and C5a

- phagocytic cels are attracted to the site of the antigen

Question 4

anaphylatoxin production and complement

Answer 4

• C3a and C5a degranulate mast cells and basophils

- granules contain potent inflammatory chemicals eg histamine

Question 5

lysis of organsims and complement

Answer 5

-coated with specific antibody and recruit C8 and C9

Question 6

inhibitor of the classical complement pathway

Answer 6

-C1-inhibitor

Question 7

alternative complement pathway

• how is it activated
• proteins involved

Answer 7

• by bacterial or viral products (LPS)
• proteins involved: C3b, factor B and D, properdin
• together generate C3bBbP which splits c3 into C3 and Cb and continues the the classical cascade

Question 8

inhibitors of the alternative pathways

Answer 8

-Factor H and Factor I are inhiibitors of the alternative pathway and regulate the activation of the system

Question 9

lectin pathway

Answer 9

• activated by organisms with mannose on their surface
• proteins involved: MBL (mannose binding lectin), MASP1, MASP2, C4, C2
• C4b2b cleave C3 and this cascade enters the classical pathway

Question 10

absence of C1q, C2, or C4

Answer 10

-associated with SLE

Question 11

absence of C3

Answer 11

-severe recurrent bacterial infection

Question 12

absence of C5

Answer 12

-bacterial infection

Question 13

absence of C6,7,8

Answer 13

overwhelming neisserial infection

Question 14

absence of alternative pathway components

Answer 14

-recurrent bacterial infections

Question 15

absence of lectin pathway proteins

Answer 15

-infection in childhood

Question 16

absence of C1-INH

Answer 16

-hereditary angioedema

Question 17

hereditary angioedeme

Answer 17

• rare AD
• disfunctional C1-INH
• recurrent episodes of angioedema
• without urticaria or pruritus, which most often affect the skin and mucous tissue of the upper resp tract
• laryngeal involvement may cause fatal asphyxiation