B cell immunity Flashcards Preview

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Flashcards in B cell immunity Deck (19):
1

IgD

role is to ensure autoreactive cells don't get out into the periphery

2

rearranged heavy chain and surrogate light chain

signals end of heavy chain rearrangement, cell survival, cell proliferation

leads to light chain rearrangement

3

RAG-1 and RAG-2

involved during heavy and light chain rearrangement

4

Immature B cells in bone marrow

no reaction with self antigen leads to B cell moving to the blood and expressing IgD and IgM.

reaction with self antigen leads to immature B cell retained in bone marrow (undergoes receptor editing)

5

receptor editing

rearrangement of light chain genes that occurs when B cell reacts to self antigen in bone marrow

allows immature B cell to make a new light chain, IgM with different specificity

6

what happens when B cell sees antigen without T cell help?

B cell dies or becomes totally unreactive

7

what happens if B cell fail to enter lymphoid follicles?

it dies. B cells have half life of 3 days

8

dendritic cells

takes infection from site of infection to lymph node to stimulate adaptive immunity.

9

how do B cells see antigen

natively. by binding to the entire antigen, it can produce a more effective antibody

10

TI-1 antigen

does not activate T cell. can activate B cell. results in innate response, no T cell response.

bacterial lipopolysaccharide, brucella abortus

11

TI-2 antigen

does not activate T cell. can activate B cell. results in innate response, no T cell response.

pneumococcalpolysaccharide, salmonella

12

without T cells

no immunologic memory, no memory B cells, no IgG, only IgM responses, responses are short lived

13

how can B cells be activated without T cells?

For TI-1, TLR4 (toll receptor) is a signal that can replace T-cell signals

For TI-2, by crosslinking of their receptors by antigens. repeated antigen increase signal to B cell.

14

memory cells

IL-4 from T-cell allows memory cells to differentiate. results in a cell that can grow, proliferate and stimulate T cells.

15

plasma cells

IL-10 from T-cell allows plasma cells to differentiate, results in a cell that does not grow, proliferate, and cannot stimulate T cell. High rate of IgG secretion.

16

hyper IgM syndrom

No germinal centers. caused by lack of CD40 ligand. no critical signal for B cells from T cells. No class switching.

17

germinal centers

class switching and affinity maturation take place here

18

follicular dendritic cells

hold antigen for B cells to examine. does not process them.

19

what activates the B cell and allows it to differentiate

antigen binding to B-cell receptor delivers first signal

T helper cell delivers the second signal via CD40 ligand and cytokines