Lymphocytes II

Question 1

T cell activation

Answer 1

MHC II Ag - to CD4 T cell
MHC I Ag - to CD8 T cell

costimulation - B7 and CD28

requires 2 signals**

Question 2

B cell activation

Answer 2

B cell receptor mediated endocytosis -foreign antigen on MHC II and recognized by TCR on CD4 T cell - signal 1

CD40 on B cell - bind CD40L on Th cell - signal 2

CD4 T cell - secrete cytokine - determine Ig class switch of B cell

Question 3

antibody structure

Answer 3

Fab - variable - L and H chain region

Fc - IgM and IgG - fixe complement - close to hinge

heavy cahin - Fc and Fab regions

light chain - only Fab region

Question 4

Fab regions

Answer 4

antigen binding

Question 5

antibody diversity

Answer 5

rearrangement VJ and VDJ genes

somatic hypermutation

Question 6

Fc region

Answer 6

constant
carboxy terminal
carb side chain
determine isotype

Question 7

mature B cells

Answer 7

express IgM and IgD

CD40 induce isotype switch - to IgA, IgE, and IgG

Question 8

IgG

Answer 8

main Ab - delayed response to antigen

most abundant in serum

fix complement
cross placenta
infant - passive immunity

Question 9

IgA

Answer 9

mucous membrane defense

does not fix complement

monomer in circulation
dimer when secreted

produced in GI tract - peyers patches

most produced - but low in serum

Question 10

released into tears, saliva, mucus, breast milk

Answer 10

IgA

Question 11

IgM

Answer 11

immediate response to antigen

fix complement
does not cross placenta

monomer on B cell

pentamer when secreted

Question 12

IgE

Answer 12

bind mast cell and basophil

cross linked when exposed to allergen

type I hypersensitivity

Question 13

thymus independent Ags

Answer 13

Ag lack peptide component cannot be presented by MHC to T cells

weak or nonimmunogenic

vaccine - require booster and adjuvant

Question 14

thymus dependent Ags

Answer 14

antigen with protein component

immuno memory occur
-bc B cell and CD4 T cell CD40 interaction

Question 15

acute phase reactants

Answer 15

induced by IL-6 mainly

signify inflammatory process

Question 16

C-RP

Answer 16

measure of inflammation

Question 17

ferritin

Answer 17

bind and sequester iron

acute phase reactant

Question 18

fibrinogen

Answer 18

coag factor

acute phase reactant

Question 19

hepcidin

Answer 19

prevent release of iron bound by ferritin

acute phase reactant

Question 20

serum amyloid A

Answer 20

acute phase reactant

prolonged elevation = amyloidosis

Question 21

class complement pathway

Answer 21

IgM

IgG

Question 22

alternative complement pathway

Answer 22

microbe surface molecule

Question 23

lectin complement pathway

Answer 23

mannose -other sugars on microbe surface

Question 24

anaphylaxins

Answer 24

C3a
C4a
C5a

Question 25

opzonin

Answer 25

C3b

Question 26

MAC complex

Answer 26

C5-9

Question 27

neutrophil chemotaxis

Answer 27

C5a

Question 28

inhibitors of complement

Answer 28

so don’t attack self cells

CD55
C1 esterase inhibitor

Question 29

C1 esterase inhibitor deficiency

Answer 29

hereditary angioedema

CI - ACE Is

Question 30

C3 deficiency

Answer 30

risk severe recurrent pyogenic sinus and resp infections

susceptible to type III HS

Question 31

C5-9 deficiency

Answer 31

susceptible to neisseria infection

Question 32

DAF deficiency

Answer 32

complement mediated lysis of RBCs and paroxysmal nocturnal hemoglobinuria

Question 33

C3 convertase of alternative

Answer 33

C3bBb

Question 34

C3 converatase of lectin and classic

Answer 34

C4b2b

Question 35

C3 convertase

Answer 35

cleave C3
to C3b and C3a

C3a - anaphylatoxin
C3b - helps to form C5 convertases

cleaves C5b and C5a

C5b - activate MAC complex
C5a - attract neutrophils