Lecture 15 Humoral Immunity

Question 1

Antibody effector functions

Answer 1

Neutralization;
Opsonization;
Complement activation

Question 2

BCR functions

Answer 2

1. Initiate signal cascade by binding antigens
2. Deliver antigen to intracellular sites for processing/presentation (MHC II)

Question 3

What are the two ways B cells can be activated?

Answer 3

thymus-dependent antigens
thymus-independent antigens

Question 4

Follicular helper T cells help with ______ and _________. This process takes _______.

Answer 4

affinity maturation and class switching; longer

Question 5

_____ antigens cause B cells to activate quickly. It is ___ specific.

Answer 5

thymus-independent; not

Question 6

The primary response of B cells occurs in ___ phases

Answer 6

2

Question 7

Phase 1 of the primary response involves

Answer 7

antigen encounter;
Bcell Tcell interaction; B cell proliferation

Question 8

What is involved of Phase 2 of the B cell response?

Answer 8

somatic hypermutation; class switching

Question 9

What signals do TFH send to B cells to activate them/control differentiation?

Answer 9

CD40:CD40L
IL21
CD21 and CD19

Question 10

What does CD40:CD40L interaction do to B cells?

Answer 10

activates NFkappaB and enhances survival (anti-apoptotic Bcl-2)

Question 11

IL21 signaling in B cells

Answer 11

activate STAT3, enhances proliferation and differentiation into plasma cells and memory B cells

Question 12

CD21 and CD19 interact with

Answer 12

C3b

Question 13

The concept of linked recognition is

Answer 13

T and B cells respond to the same antigen (can be distinct but linked)

Question 14

T cells in T cell zones have ____ receptors and respond to ____ and ____

Answer 14

CCR7;
CCL19 and CCL21

Question 15

B cells in B cell zone have ____ receptors and respond to _______, expressed by follicular dendritic cells

Answer 15

CXCR5;
CXCL13

Question 16

structure/function of follicular dendritic cells

Answer 16

octopus, lots of arms/projections, it acts as a net not a phagocytoser and traps B cells

Question 17

When B cells are engaged they begin to upregulate _____ and move halfway to meet with active TFH (who begin to express _______). After communication, they _________

Answer 17

CCR7; CXCR5; downregulate

Question 18

Resting B cells -> ______ -> plasma cells

Answer 18

plasmablasts

Question 19

resting B cells do not have a high rate of _____

Answer 19

Ig secretion

Question 20

Plasma cells cannot

Answer 20

grow, class switch, do somatic hypermutation

Question 21

plasma cells have high surface ___ and _____ and low surface _____

Answer 21

IgA and E;
IgG

Question 22

Structure of germinal center

Answer 22

light zone, dark zone, mantle

Question 23

B cells proliferate at the highest rate in the _____ zone

Answer 23

dark

Question 24

Many TFH cells are present in the ____ zone

Answer 24

light

Question 25

cyclic reentry into the dark zone occurs due to _____ expression (responding to _____)

Answer 25

CXCR4; CXCL12

Question 26

B cells undergo somatic hypermutation in the ___ zone. They drop _____ expression and migrate into the ____ zone.

Answer 26

dark; CXCR4; light;

Question 27

_______ are present in GC with the antigen they caught. They can present to B cells with high affinity for the antigen (due to ________)

Answer 27

Follicular DCs; affinity maturation

Question 28

TFH will send _____ signals to B cells that present the antigen to them(_________). B cells that receive this signal will reenter the ___ zone and continue to mutate.

Answer 28

CD40 (survival); cross link dark

Question 29

_____ made by TFH direct class switching

Answer 29

cytokines

Question 30

_____ direct isotypes IgG1, IgE

Answer 30

IL-4

Question 31

IFN-gamma directs _____ and _____

Answer 31

IgG3 and IgG2a

Question 32

_______ directs IgG2b and IgA

Answer 32

TGF-beta

Question 33

______ directs IgG3, IgG1, and IgA

Answer 33

IL-21

Question 34

IL5 directs ____ and ______

Answer 34

IgG1 and IgA

Question 35

Which antibodies activate complement system?

Answer 35

IgM IgG3 and IgG1

Question 36

_____ can transport across epithelium

Answer 36

IgA (dimer)

Question 37

Which antibodies involved in neutralization?

Answer 37

IgGs and IgA

Question 38

sensitation of mast cells antibody

Answer 38

IgE (G1 and G3 to some extent)

Question 39

diffusing into extravascular sites

Answer 39

IgGs and A (monomer)

Question 40

opsonization antibody class

Answer 40

G1, G2, G4ish, Aish

Question 41

transport across placenta antibody class

Answer 41

IgG1 and IgG3 somewhat G2 and G4

Question 42

_____ has secretory component that binds to polymeric Ig receptor (pIgR)

Answer 42

IgA

Question 43

IgA and IgG can neutralize ______ and ________

Answer 43

bacterial toxins and viruses

Question 44

Opsonization function

Answer 44

antibody dependent cellular activation antibody-virus engages Fc receptor to destroy virus

Question 45

C1q can bind to _______ form of IgM (5-10% is isomeric)

Answer 45

planar

Question 46

at least 2 IgG can cluster to bind _____

Answer 46

C1q

Question 47

antigen:antibody complexes lead to activation of _______ and deposition of ____. _____ can bind and phagocytic cells in the liver and spleen can dispose of complex

Answer 47

complement; C3b; CR1

Question 48

aggregation of ig on bacterial surface leads to _______ of Fc receptors and activation of ______.

Answer 48

cross linking; macrophages

Question 49

Fcgamma R3 receptors on NK cells recognize antibodies ___ and ___ bound to target cells through ___________

Answer 49

G1 and G3; antibody-dependent cell mediated cytotoxicity

Question 50

Mast cells and basophils bind IgE via ________ receptor for ________

Answer 50

Fc-epsilon, parasitic infections