16 – Linking innate & adaptive: T cell proliferation (signal 1 & 2) Flashcards
IL-2 induces
proliferation
IL-2 = example of
autocrine cytokine response system
T cell – produce cytokine & receptor for it
Binding of ligand = induce strong proliferation signal during activation stages
IL-2 proliferation outcome =
activation & robust proliferation
Production of memory (M) & effector (E) clonal cell populations
IL-2 require … and … .
activation of…. of….
Signal 1&2
Activation of transcription of:
IL-2 gene – the cytokine
IL-2Rα gene – part of receptor
-Aka CD25
-Not expressed at baseline
2 separate genes – transcription of these =
regulated differently
signaling cascade activating transcription factors going to nucleus =
- Signal 1 & signal 2 = required to initiate downstream signaling cascade activation of TF
- Activation of TF
- Activates IL-2 gene & IL-2 receptor α chain
IL-2 R 𝛽𝛾-chains, what about their affinity
constitutively expressed on cell surface
But have lower affinity for IL-2
When IL-2 Rα available & affinity?
affinity of receptor for IL-2 = higher
Resting/naive T cell
No IL-2
No IL-2R α chain
yes IL-2 R 𝛽𝛾-chains
T cell receives signal 1 & 2
transcription of IL-2 & IL-2Rα
IL-2 = secreted
High affinity IL-2R expressed
Signaling from IL-2 from IL-2R = result in
proliferation & help modulate T cell differentiation for some T cell subset
IL-2 binds its receptor in …. fashion primarily, Can also act in … fashion for ….
autocrine
paracrine fashion for Treg
Treg
A regulator protein for T cell cloning
Act as a sink for IL-2 to limit its availability to other cells
-don’t produce their own IL-2 but have IL-2R α chain on their IL-2R
signal 1 & 2 converge to
activate transcription of Il-2&IL-2R α chain receptor - CD25
