I&I adaptive immunity 2 Flashcards
Where do T cells undergo early developmental process and what does this generate?
T cell undergoes early developmental process in the thymus
to generate T cells expressing clonal TCR (T cell receptor)
What does the CD4 TCR recognise?
CD4 TCR recognises MHC II/peptide complex
What does the CD8 TCR recognise?
CD8 TCR recognises MHC I/peptide complex
What do MHC present?
MHC class I presents endogenous antigen
What do MHC class 2 present?
MHC class 2 presents exogenous antigen
Where are naive T cells are activated?
Naïve T cells are activated in secondary
lymphoid organs: spleen and LNs
What are the steps involved activation of naive T cells?
- Naive T cells circulate through lymph nodes and find antigens
- Then there is activation of naive T cells in lymph node, development of effector cells
- Then there is activation of effector T cells at site of infection; eradication of microbe
What express high levels of MHC class II?
Only activated professional APCs express high
levels of MHC class II
What do APC’s express?
These APCs also express co-stimulatory
molecules.
What are the 3 different signals that T cells need in order to be fully activated and differentiated into effector or memory T cell?
- Signal 1: Antigen recognition
- Signal 2: Co-stimulation
- Signal 3: Cytokines
What is the 1st signal that initiates the immune response?
Is the signal that initiates the
immune response, so that the
immune response is antigen-
specific
What are the steps involved in the 1st signal:antigen recognititon?
- TCR in T cell recognises the
antigen in the context of MHC:
* CD4 TCR recognises MHC
II/peptide complex
* CD8 TCR recognises MHC
I/peptide complex
What is MHC class 1 present in?
Present in all
nucleated cells
(including
professional APCs)
What does MHC class 1 do?
Continuous sampling
of peptides from
within the cells
(cytosol)
What is MHC class I recognised by?
Recognised by CD8+ CTL
