Complement/Humoral

Question 1

neutralize microbes and microbial toxins

Answer 1

IgM, IgG, IgA - bind viruses and prevent attachment to cells; binds toxins and prevent toxin from binding receptors on cells

Question 2

opsonophagocytosis

Answer 2

IgM, IgG - coat microbe which then bind to macrohpages and neutrophils via Fc-gamma-R or complement receptors

induces phagocytosis, ROS, NO, proteolytic enzymes

major mechanism for encapsulated bacteria - spleen is the major site for phagocytosis

complement: C3b, C4b, iC3b, iC4b

Question 3

antibody-dependent cellular cytotoxicity

Answer 3

IgG - once bound to antigen, binds to Fc-gamma-R on NK cells; NK cells then release perforin and Granzyme B

Question 4

eosinophil/mast cell

Answer 4

IgE binds to Fc-epsilon-R which causes the eosinophils and mast cells degranulate

different from the others because IgE does not bind to the antibody

Question 5

complement

Answer 5

IgM, IgG

Question 6

protect mucosal surfaces

Answer 6

IgM, IgA - IgA production is induced by TGF-B which is produced in mucosal-associated lymphoid issue (MALT)

Question 7

protect neonates

Answer 7

IgG binds FcRn, which transports IgG across placenta

Question 8

M cells

Answer 8

transport antigens from lumen into Peyer’s patch (small lymph node)

Question 9

alternative pathway of complement activation

Answer 9

either spontaneous C3 hydrolysis to get C3b or get C3b from classical/lectin pathway -> C3b + microbial charged surfaces -> add factor B to get C3bB -> factor B cleaved by factor D -> C3bBb -> add factor P to get a C3 convertase: C3bBbP -> can get C5 convertase by adding C3b to C3bBb

Question 10

lysis of cell membranes

Answer 10

neisseria: Mac complex

Question 11

inflammation

Answer 11

chemotaxis (neutrophils): C5a&raquo_space; C5b67

mast cell degranulation: C5a&raquo_space; C3a, C4a (anaphylatoxins)

Question 12

solubilizaiton and clearance of immune complexes from circulation

Answer 12

C3b, iC3b

Question 13

B lymphocyte co-activation

Answer 13

C3d

Question 14

opsonic and adhesion complement receptors

Answer 14

CR3, CR4 > CR1 (phagocytes)

Question 15

anaphylaxis

Answer 15

C5aR > C3a/4aR (mast cells, basophils and smooth muscle cells)

Question 16

chemotactic receptors

Answer 16

C5aR (neutrophils)

Question 17

clearance receptor for soluble immune complexes

Answer 17

CR1 (erythrocytes)

Question 18

B cell co-receptor

Answer 18

CR2 complex

Question 19

LFA-1

Answer 19

CD11a + CD18

Question 20

CR3

Answer 20

CD11b + CD18

Question 21

CR4

Answer 21

CD11c + CD18

Question 22

measuring complement

Answer 22

ELISA (immmunoassay): C1, C2, C3, C4, B

total hemolytic complement: CH50 units - measures classical pathway components

opsonophagocytic activity: uptake of antibody-coated bacteria by neutrophils in the presence of fresh nonimmune serum

Question 23

block formation of C3 convertase

Answer 23

DAF prevents factor B from binding C3b

CR1 prevents Factor B from binding C3b

Factor I and MCP degrades C3b and C4b

Factor H binds C3b and acts as a cofactor for Factor I

C4b-binding protein binds C4b

Question 24

blocks MAC

Answer 24

S protein and Homologous restriction factor

Question 25

anaphylatoxin inhibitor (AI)

Answer 25

cleaves and inactivates C3a, C4a and C5a