Complement Cascade (Bowden)

Question 1

C’ functions

Answer 1

triggering amplification of inflammation reactions
attracting phagocytes by chemotaxis
clearance of immune complexes
cellular activation
direct microbial killins
important development of humoral responses

Question 2

Anaphylatoxins

Answer 2

the a fragments from C’ cascade. play a role in initiating localized inflammatory response

Question 3

C’ role in classical pathway

Answer 3

activated by Ab binding to Ag
viruses and bacteria.
assists Ab and adaptive immune system

Question 4

C’ role in alternative pathway

Answer 4

independent of Ab. Innate immunity

always on guard.- surveillance

Question 5

Which C’ pathway is most rapid and efficient

Answer 5

Classical

Question 6

How can we distinguish self membrane from non-self

Answer 6

self: high [ ] sialic acid & rapidly inactivates bound C3b via Factor H
non: low [ ] sialic acid & bound C3b remains active longer, ex: bact/yeast walla and viral envelopes

Question 7

Two main types of Regulation in C’ cascade

Answer 7

proteolytic digestion

binding with dissociation

Question 8

What acts as opsonin, what R do they bind to

Answer 8

C3b and C4b

these bind to CR1,-CR4 on phagocytes

Question 9

What else activates phagocytic cells

Answer 9

C5a anaphylatoxin thru

increase # C’R on cell surface

Question 10

What removes immune complexes with C3b

Answer 10

monocytes and phagocytes–>liver

erythroctyes–>spleen

Question 11

How many MACs does it take to lyse RBC

Answer 11

1

Question 12

What type of cells are resistant to MACs

Answer 12

nucleated. can endocytose MACs because they are repairing membrane damage
some cancer cells have this ability

Question 13

Activation of complement results in what direction of fluid flow

Answer 13

influx of fluid

Question 14

Fucntions of anaphylatoxins

Answer 14

bind R of mast cells and blood basophils to induce degranulation
induce sm. mm contraction to inc vascular perm
induce monocytes and neutrophils to adhere endothelial cells–>extravasation

Question 15

Which C’ a fragment is the most potent

Answer 15

C5a

Question 16

Prokinin

Answer 16

C2a cleaved by plasmin to yield kinin–> EDEMA

Question 17

What are they general schemes of many complement particle pathways to degradation

Answer 17

Opsonization of C3b or C4b and phagocytosed
Complement mediated- MAC formation= osmotic lysis
Stimulation of inflammatory rxns via a fragments(destruction is by leukocytes)

Question 18

C3 deficiencies

Answer 18

life-threatening. severe recurrent infections right after birth.
C3b plays in opsonin of infectious material

Question 19

What types of deficiencies mimic C3 deficiency

Answer 19

Facto H and I because unregulated C3b generation exhausts C3 from serum

Question 20

MAC deficiencies

Answer 20

generally healthy

increase in infection by neisseria gonorrhoeae and N. meningitidis

Question 21

Most common early C’ deficiency

Answer 21

C2 deficiency: high degree of systemic lupus erythematosis. inability to clear immune complexes.
this activates alternative pathways and leads to local inflammation
may promote breakdown of self antigens–>autoimmunity

Question 22

C1 inhibitory deficiency

Answer 22

C1 not regulated. C4 and C2 levels are low

experience Hereditary Angioneurotic edema

Question 23

Hereditaty Angioneurotic edema symptoms and Tx

Answer 23

attacks of swelling, no obvious cause. extremities, face and GI tract. upper respiratory tract
Tx: androgens to produce C1inhibitor

Question 24

DAF deficiency

Answer 24

Paroxysmal Nocturnal Hemoglobinuria
acquired hemolytic disorder with spontaneous episodes of RBC lysis
Increased sensitivity to lysis
Treat with EPO

Question 25

Epstein-Barr virus (herpesviridae)

Answer 25

uses CR2 as a R for attachment

Question 26

Measles virus (paramyxovirdidae)

Answer 26

uses MCP(CD46) as R

Question 27

The west nile virus (flavivirdae)

Answer 27

C3b coats viral particle and then gains entry into cell via the CR3 Receptor