L18: T And B Cell Co-operation Flashcards
What antibodies does naive B cells have on their surface
Igm
IgD
What antibodies does activated B cells have on their surface
Igg
Ige
Iga
What are the 2 responses that occur when you give someone a vaccination then a booster in a t dependent response
Primary response
Secondary response
What happens to the antibody levels in the primary response
Increase then decrease a little bit but doesn’t not level back to 0
What happens to the antibody levels in the secondary response
Antibody levels increase more and faster
Before immunisation which antibodies are present
Igm
Igg
After immunisation which antibodies are more present
Igg
Iga
In a vaccination with a t independent response what happen to the antibody levels in the primary response
Increase then go back to 0
What happens in the secondary response in a vaccination with t independent response
The same thing in the primary response
Which cells activate CD4 T cells
Dendritic cells
Which cells activate B cells
CD4 T cells
What are the primary lymphoid tissue
Bone marrow
Thymus
What are the secondary lymphoid tissue
Spleen
Lymph nodes
From which vessels does dendritic cells enter into the lymph node
Afferent lymph vessels
From which layer in the lymph node does the adaptive immune response start
Para cortex (t zone)
From which vessels does the t and B cells enter from
High endothelial vessels
Where are the B cell area follicular dendritic cells
In the cortex
What other structures is in the cortex
Germinal centre
Where does somatic hyper mutation and class switching occur
In the germinal centres
What are the 2 types of pulp the spleen contains
Red pulp
White pulp
What does the red pulp contain
Red blood cells
Platelets
Macrophages
What does the white pulp contain
Most lymphocytes
What are the zones/layers in the white pulp
T zone
Follicle
What are in the t done
Dendritic cells
T cells
B cells
What are in the follicles
Germinal centres
Which antibodies are produced in the t dependent antibody response
Igg
Iga
Ige
What are the affinity of the antibodies in t dependent antibody response
High affinity
What are the main antibodies produced in the t independent response
Igm
What is the affinity of the antibodies in the t independent response
Low
At which centre does the t dependent antibody response occur
Germinal centre
Where does the t independent response occur
Outside the follicles
What do B cells do when they encounter an antigen
1) B cell receptors bind to antigen
2) antigen becomes internalises and degraded into peptide fragments
3) fragments become represented on the MHC class 2
3) MHC class 2 is recognised by CD4 T helper cell
How do CD4 follicular T cells become activated
When they encounter MHC class 2 on dendritic cells
When CD4 follicular T cells are activated what do they recognise
MHC class 2 on the B cells
What happens to the B cells when they are activated
Migrate to the germinal centres in the follicle for a t-dependent response
Or migrate to the extra-follicular for a t- independent response
When does the B cell enter the extrafollicular cells for a t-independent response
When B cells don’t interact with dendritic cells and t follicular helper cells
Which antibodies are produced in the germinal centres
Igg
Iga
Ige
What are the 2 key processes that occur in the germinal centres
Somatic hyper mutation
Class switching
Which cells are involved in the germinal centres
Centroblasts
Centrocytes
Follicular dendritic cells
Follicular t helper cells
What are the 2 zones in the germinal centres
Light zone
Dark zone
Which zone are centroblasts found in
Dark zone
Which zone are centrocytes found in
Light zone
Where are follicular dendritic cells found in
The light zone
Describe what happens in the t dependent response in the germinal centres
1) in the dark zone centroblasts undergo somatic hyper mutation by the AID gene on the v region
2) centroblasts move into the light zone to become centrocytes
3) centrocytes with high affinity interact with the follicular dendritic cells that present antigen on them
4) t follicular helper cells provide signal to the centrocytes
5) centrocytes become plasma cells or memory cells
6) the centrocytes also undergo class swithching by the AID gene which act on the c region
7) immunoglobulin changes to IGG, IGA,IGE
8) plasma cells then release igg,iga ige
