B Cell Development and Immunity Flashcards Preview

Immunology > B Cell Development and Immunity > Flashcards

Flashcards in B Cell Development and Immunity Deck (22):
1

Where is hematopoiesis in the fetus?

developing liver

2

Where the primary site of hematopoiesis in adults?

bone marrow

3

How long can naive B cells circulate before apoptosis if they don't encounter Ag?

2-3 days

4

What gene is expressed during heavy and light chain rearrangement?

RAG

5

When is TdT expressed?

From heavy chain rearrangment to light chain arrangment, but begins going away as light chain since no N regions are added

6

When are surrogate light chain genes expressed?

Only in heavy chain rearrangment region

7

What is receptor editing?

Immature B cells in the BM that are self-reactive will edit the light chain to try to eliminate self-reactivity, if it fails, self-reactive B cell retained in BM

8

What happens to a B cell that see Ag in an early stage without T cell help?

anergy

9

Can B cells recognize Ag presented on dendritic cells?

No, they must see ag in native conformation

10

What is an immune synapse?

Ag-activated B cells act as APC to T cells, induces immunological memory

11

What type of antigen is LPS?

T-independent 1 (TI-1)

12

What type of antigen is bacterial DNA?

TI-1 antigen that can activate B cells specific for bacterial surface Ag

13

How are T-independent responses different from T-dependent responses?

no memory, no IgG response, mainly IgM, short-lived

14

What are TI-1 antigens? What signal replaces T cell signal? What is activated?

LPS, bacterial DNA
-TLR-4 replaces T cell signals
-activates nonspecific B cells to produce IgM against bacterial surface

15

What are TI-2 antigens?

repeating polysaccharides with same epitope that causes crosslinking of receptors to activate

16

In what organ is the highest concentration of B cell development? what regions?

lymph nodes, in the medullary cords and germinal center

17

What is different about follicular dendritic cells? Where are they found? What is their purpose?

don't process Ag, found in germinal centers, present Ag to B cells

18

Where is a focal point for B cells to undergo cell division, class switching and affinity maturation?

germinal centers

19

What causes hyperIgM syndrome?

lack of CD40 because of lack of T cells, no class switching, no germinal centers

20

What is a centrocyte?

dividing B cell in germinal center

21

What will IL-10 induce a B cell to differentiate into?

plasma cell

22

What will IL-4 cause a B cell to differentiate into?

memory B cell