Lecture 15

Question 1

thymus-dependent b cell-mediated immunity involves (general components)…

Answer 1

• b cell
• protein antigens (TD antigen)
• T cells (helper)

Question 2

thymus-independent b cell-mediated immunity involves (general components)…

Answer 2

• multivalent antigens (usually carbs) w repeating eptopes (TI-1 / TI-2)
• B cell (BCR clustering)

Question 3

TI-1s activate B cells via…

Answer 3

TLRs

Question 4

TI-2s activate B cells via…

Answer 4

compliment system

Question 5

what is linked recognition?

Answer 5

the pathogen presented to the helper T cell is identical to that which was recognized by the respective b cell.

Question 6

What are three essential components of thymus-dependent b cell-mediated immunity? What do they do?

Answer 6

1. CD40-CD40L (signal survival and proliferation)
2. IL-21 (signals proliferationa nd differentiation)
3. cytokines (signal isotype switching)

Question 7

where do antigen-binding b cells meet T cells?

Answer 7

the border between the t-cell area and b-cell follicle in the secondary lymphoid organs.

Question 8

describe the process of b-cell mediated immunity.

Answer 8

1. b-cells in the follicles produce CXCR5, and t-cell cells in the t-cell zones produce CCR7
2. upon activation, b cells upregulate CCR7 and EB12 receptors. t cells upregulate CCR5 receptors. they are therefore drawn together at the borders of their respective zones.
3. the cells aggregate at the periphery of the follicles.
4. some b cells becomes a primary focus, while some t cells become T follicular helper cells.

Question 9

what is a primary focus?

Answer 9

a collection of plasmablasts

Question 10

What are the three components of a follicle with a germinal center?

Answer 10

1. mantle zone (edge – contains unactivated b cells)
2. light zone (Ig testing – contains t follicular helper cells and activated b cells)
3. dark zone (Ig gene mutation – contains activated b cells)

Question 11

Ig gene mutation is mediated by ____ , and is ____ driven.

Answer 11

AID, antigen

Question 12

which types of antibodies undergo class switching (GC b cells)?

Answer 12

IgG, IgA, IgE

Question 13

what is Neutralization?

Answer 13

blocks toxins and bacteria from binding

Question 14

what is Opsonization?

Answer 14

coating the surface of a pathogen or target particle, enhancing its recognition and ingestion by phagocytes

Question 15

what mediates opsonization?

Answer 15

Fcu/γ

Question 16

what antibodies do neutralization?

Answer 16

IgG and IgA

Question 17

What antibodies do opsonization?

Answer 17

IgG

Question 18

what antibodies do sensitization for killing via NK cells?

Answer 18

IgG

Question 19

what antibodies do sensitization of mast cells?

Answer 19

IgE

Question 20

what antibodies do activation of compliment system?

Answer 20

IgM and IgG

Question 21

What is sensitization of mast cells?

Answer 21

enabling of mast cell activation and anti-parasitic function

Question 22

What initiates the compliment system? How does it do this?

Answer 22

C1q

(it binds to CRPs, and then binds antibodies binding microbes)

Question 23

If in the light zone of a GC, an Ig is found to be not reactive enough, it will…

Answer 23

return to the dark zone

Question 24

proliferating b cells in the light zone are known as…

Answer 24

centrocytes

Question 25

proliferating b cells in the dark zone are known as...

Answer 25

centroblasts

Question 26

what is the first phase of primary humoral immunity?

Answer 26

- activated and proliferating b cells are outside of the follicle (in red pulp of spleen / lymph nodes), and undergo no interaction w T follicular helper cells). - they become plasmablasts, OR becomes plasma cells who becomes memory cells.

Question 27

what is the second phase of primary humoral immunity?

Answer 27

- activated and proliferating b cells are inside of the follicle, and undergo interaction w T follicular helper cells. - They become germinal centers (secondary lympoid follicles), and then becomes memory cells.