L41. Adaptive Immunity Flashcards
Name the 2 types of adaptive immune response.
Cell-mediated response
antibody (humoral) response
Cell mediated immunity: which cells is it driven by?
T cells
Cell mediated immunity : what does it involve the activation of?
macrophages
natural killer cells
cytotoxic T-lymphocytes
Humoral immunity : which cells drive it? Why?
B-cells produce antibodies
How does immunological memory occur?
When a pathogen is remembered by a signature T cell and/or B cell receptor
What is the time frame for adaptive immunity?
4-7 days from the start of infection
Describe the 2 stages following “recognition by naïve B and T cells”.
- Clonal expansion and differentiation
3. Removal of infectious agent
Name 3 adaptive immunity receptors
- T cell receptors
- B cell receptors
- MHC proteins
What do T cells do?
Give rise to cellular immunity.
Can respond to many antigens, called “T cell repertoire”.
“Thymic education” means they only respond to foreign pathogens
What is the role of CD4+ cells?
T helper cells which help support other immune cells to fight threats
What are CD8+ cells?
Cytotoxic T cells which destroy infected self cells
What do T-regs do?
Regulate or suppress other immune cells
How do all cells start?
As naïve cells and have protein specific receptors
Name the co-receptors of the following and what they each bind to.
CD8
CD4
CD8 has a co-receptor that binds to MHC1
CD4 has a co-receptor that binds to MHC2
What is CD3?
A co-receptor involved in CD4 and CD8 T-cell activation
What are most T cell receptors made of?
alpha and beta chains
Name the 2 regions which make up the T cell receptor.
Constant region
Variable region
Which genes make up the variable region, and which chains are they found on?
V (variable) (alpha and beta)
J (joining) (alpha and beta)
D (diversity) (beta only) (closes to B in alphabet)
How are genes re-arranged, and by which enzymes?
Somatic recombination by RAG enzymes
Name the 2 types of T cell selection after the thymus interaction.
Positive selection
Negative selection
What happens to positively and negatively selected CD4/CD8 cells?
Leave the thymus and regulate in the blood/lymphatics.
*Even although cells which leave the thymus (to regulate in the blood) are educated, what cell type are they still classed as?
“Naïve T cells”
What do immature dentritic cells do?
Take up the antigen to be processed in the epidermis. They migrate to the lymph nodes and mature on the way.
What does “priming” refer to?
The 3 signals required for activation and fate determination of T cells.
Name the middle step.
- Activation of T cell by T cell receptor and MHC2. (this is known as anergy if step 2 is absent)
- ___________________
- differentiation into subsets of effector T cells (using cytokines)
- Activation of T cell by T cell receptor and MHC2. (this is known as anergy if step 2 is absent)
- Survival and clonal expansion of T cells using CD28
- differentiation into subsets of effector T cells (using cytokines)
Name the 5 CD4 cell subsets.
Th1 Th2 Th17 Tfh Treg
Give the role and source of Th1
supporting macrophage function
interferon y
Give the role and source of Th2
supporting humoral responses and allergic reactions
interleukin 4,5 and 6
Give the role of Th17
Supports innate immune responses
Give the role of Tfh
T follicular helper cells work with b cells for antibody production
Give the role of Tregs
Immune suppression, inhibit T cell and dendritic cell activation.
What activates CD8 cells?
T cell receptor and MHC1 interaction
What does CD8 activation result in?
Induces host cell apoptosis
produces enzymes
What is the activation of T cells called? What does it result in?
Activation is called priming.
Results in the generation of memory T cells
