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Flashcards in Adaptive Response Deck (15)
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1

Why do self reactive B cell receptors arise?

What happens to them

Random recombination of V gene

Die through apoptosis (-ve selection)

2

What are the five classes of antibody?

IgG
IgA (dimer)
IgM (pentamer)
IgD
IgE

All have different heavy chain

3

What is most common immunoglobulin?

IgG

4

What type of infection involves what Ig?

Primary : IgM
Secondary: IgG
Mucosal: IgA
Parasitic: IgE
During pregnancy: IgG

5

Outline path from naive B cell to antibody production

Enter circulation
Encounter antigen
Activated by CD4
Proliferate
Differentiation into plasma cell (class switching)
Antibody secretion

6

What is the important difference between B cell receptors and T cell receptor generation?

T cell repertoire is profoundly influenced by the MHC allotype of an individual through selection

7

How are T cell receptors selected for in regard to MHC?

Beta chain expression is key stage
Alpha chain then rearrange so for complete TCR
Positive selection removes weak MHC
Negative selection removes too strong MHC

8

What two types of T cell can arise due to interaction with MHC Class 2?

Th1 or Th2
Dependent on type of antigen. Each secretes different cytokines. Th2 interacts with B cells. Th1 activates macrophage

9

What are the four main functions of a CD4?

Cytokines secretion
CD8 help
B cell help
Antibody class switching

10

Outline CD8 action

Cytotoxic activity
Release granules containing perforin, forms pore, and granzyme, lytic enzyme.

11

Where does antigen presentation occur?

Lymph nodes

12

What do antibodies do?

Antibodies coat pathogens (opsonise) and target them for phagocytosis

13

What is difference between affinity and avidity?
Which Ig have highest?

Affinity: strength of binding, highest in IgG
Avidity: overall binding capacity, usually no. of binding sites per molecule = IgM highest

14

What happens to affinity over repeated infections?

Increased affinity of IgG antibodies due to somatic hypermutation

15

What is starting antibody before class switching?

IgM