T cell activation Flashcards
How are dendritic cells activated to an invader
-Neutrophils/macrophages release TNF
-Viral infection cells- release interferon
-Pattern-recognition receptors (TLR)
What is the eye of the T cell
TCR (t cell receptors)
What are the 2 forms of T cell receptors
Alpha-beta and gamma-delta
How many antigens does a TCR recognize
1
What is the most common TCR
alpha-beta
What is the traditional TCR
alpha-beta
What do the alpha-beta receptors of TCR recognize
both MHC molecule and peptide bound to it
what are non-traditional TCRs
gamma-delta
What is RAG deficiency
No b cells or T cells- good for studying nk cells or macrophage function, bc studies don’t have lymphocytes (but bad if you’re a person with this)
What co-receptor (CD4 or CD8) do non-traditional TCRs have
neither CD4 or CD8
Where do you find gamma-delta T cells
intestine, uterus, tongue
What percent of T cells are NKT cells
1%
What do NKT cells recognize
lipids presented by non-classical MHC molecules
What are the components of T cell receptors
alpha-beta (antigen recognition) and CD3 (signaling)
co-receptors
CD4 or CD8 (CD4= helper, CD8=cytotoxic)
What are intracellular vs extracellular infections in T cells
viruses / cancer, vs Bacteria
Which MHC goes with CD4
MHC2
Which MHC goes with CD8
MHC1
What will TCR binding to antigen cause
Nothing- TCR binding to the antigen alone is not sufficient to activate T cell
What causes T cell activation
- Need PAMPS, DAMPS, TNF from neutrophils- co-stimulation
What is one important co-simtulation example
CD28 TCR and B7 antigen
How long does the APC need to hold to the T cell to activate it
24 hours
What happens if there is no co stimulation vs when you do
No co-stimulation: No t cell response- no response or tolerance
co-stimulation: T cell survival, proliferation, differentiation, has response
What does IL2 do and what produces it
-make T cell long lived, develop further
- T cell produces it and it acts on itself (autocrine)
What are the 3 things you need for T cell activation
- Antigen recognition
- Costimulators
- IL2
How do cytotoxic cells kill invadors
Perforin perforates cell membrane and infuses Granzyme which tells cell to induce apoptosis.
- T cell binds to cell, cell turns itself off, shrivels up and dismembers itself in a non-inflammatory (mostly) way.
