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Flashcards in B-cell Immunity Deck (23):
1

Give 6 properties of B-1 cells?
V-region Repertoire
Location
Requirement for T cell
Memory
VDJ rearrangement
Isotype switch

restricted v-region repertoire
body cavities(peritoneal, pleural)-don't find them in blood
no tcell help
no memory development
do VDJ rearrangement
no isotype switch
-

2

Give 4 properties of B-1 cells?
V-region Repertoire
Location
Requirement for T cell
Memory

restricted v-region repertoire
body cavities(peritoneal, pleural)
no tcell help
no memory development

3

Where are marginal zone B-cells located?

Spleen-at the interface of circulation and lymphoid tissue
properties like B-1 cells

4

How does size, route, similiarity to self protein, adjuvants affect immunogenicity?

Better-->worse
Large-->small
Subcutaneous, intraperitoneal, intravenous or intragastric
Multiple differences-->few
slow release--> rapid release

5

What is a common adjuvant?

alum
composition: aluminum hydroxide gel
-delayed release of antigen; enhanced macrophage uptake

6

What two signals do B-cells (conventional B-2 cells) need to be activated?

1. IgM takes up antigen and presents it on the surface (MHC class 2)

2. t cells recognize this antigen and stimulate cytokines which cause b-cell to proliferate and differentiate into antibody producing cells (plasma cells)

For T-dependent responses, these two signals are:
1)interaction of BCR with antigen; 2) interaction of TCR with peptide/MHC complex and interaction
between costimulatory molecules CD40 (B cell) and CD40L (T cell).

7

Do carbs need t-cell help?

No

8

How do babies make anti-carb antibody(cant make T-independent response to polysaccharides)?

1. add tetanus protein to carb
2. b cell recognizes the the tetanus
3. internalizes it and presents it to t-cell
4. t-cell activates bcell
5. b-cell produces antibody against polysaccharide antigen on the surface of bacterium

9

Affinity increases in secondary responses because of what?

somatic hypermutation

10

What enzyme is responsible for isotype switch?

AID

11

What happens in the germinal center?

1. Somatic hypermutation
2. class switch recombination
3. development of memory b-cells

12

What happens in the dark zone of the germinal center?

1. somatic hypermutation
-happens primarily in the sequence of vdj genes--binding sites-capacity to bind antigen with high affinity
2. class switch

13

What is in the light zone?

follicular dendritic cells

14

How are b-cells that underwent somatic hypermutaiton selected?

Positive selection
-must have high-affinity surface immunoglobulin
-if they have BCR cross linking and T-cell help they can mature and proliferate

15

Where do the B-cells get the antigen from?

from the follicular dendritic cells

16

How do antibody response to Ti Antigen?(polysaccharide)

No germinal center
no somatic mutation
no memory
no isotype switch-IgM

17

What 2 types of arrangements are Somatic DNA Rearrangements?

VDJ rearrangement-mediated by RSS and RAGR1/RAG2
Isotype switch-by AID

18

When does isotype switch occur?

During T-dependent responses and is regulated by T-cell cytokines

19

What are geminal centers sites for?

B cell proliferation and differentiation

20

When do germianl centers form?

during immune responses
-isotype switch
-somatic hypermutaiton
-development of memory bcells

21

What happens after hypermutation?

cells with high affinity receptors are rescued from cell dealth by antigen in the form of antigen-antibody complexes bound to follicular dendritic cells followed by B-cell presentation of the antigen to Thelper cells

22

What happens after hypermutation?

cells with high affinity receptors are rescued from cell death by antigen in the form of antigen-antibody complexes bound to follicular dendritic cells followed by B-cell presentation of the antigen to Thelper cells

23

Are the antigens that trigger t-indepenedent b-cells comprised of repetitive units which triggers cross linking of the BCR?

yes