Exam 3: Cytokines Flashcards
What are cytokines?
Small, soluble proteins used by immune cells for communication
4 different cytokine properties
- Pleiotropic
- Redundant
- Synergistic
- Antagonistic
Signaling mech for many cytokines
JAK/STAT system
Role of cytokines and chemokines
fine-tuning of an immune response as it progresses
Functions of Cytokines
Stimulation (IL-2) Inhibition (TGF-β) Differentiation (IL-12, IL4, Il-23) Cell death (TNF) Chemoattract
3 modes of action
Autocrine --> Act on cell that produces them like IL-2 (respond to its own signal) Paracrine--> Act on nearby cell (class switching, T cells activating macrophages) Endocrine--> Act on distant cells via circulation (IL-1 acts on brain)
Properties of cytokines: Pleiotropy
1 cytokine has multiple effects on multiple cell types
Ex: IL-4 induces activation, proliferation, differentiation of B cells; proliferation of T cells; proliferation of Mast cells
Properties of cytokines: Redundancy
> 1 cytokine can have same effect
Ex: IL-2, IL-4, IL-5 induce proliferation of B cells
Properties of cytokines: Synergy
2 cytokines acting together have different or amplified effect than by themselves Ex: IL-4 + IL-5 dramatically increase IgE class switching when IL-5 does not have this affect alone and IL-4 exhibit lesser class switching
Properties of cytokines: Antagonism
cytokines interfere with another’s effect
Ex: IL-4 induces TH2 but inhibits TH1 and TH17; IFN-γ induces TH1 but inhibits TH2 and TH17
What cytokine(s) released by activated macrophages induce (s) change in vascular endothelium (vasodilation) that allow more leakiness of leukocytes and allow fluid to enter lymph system? (Local effect)
IL-1, TNF-α
Local effects rely on ___ levels of cytokines
Higher
Systemic effects result from TNF-α entering ____
bloodstream
Septic shock induces by __
systemic infection
Systemic infection (Too much immune response)
edema causes decreased blood volume leading to collapse of vessels, coagulation leads to multiple organ failure
What cytokines do virally infected cells secrete?
IFN-α; IFN-β
These induce resistance to viral replication replication in all cells by increasing MHC I expression and antigen presentation in all cells and activating NK cells to kill these infected cells
TH1 or TH2?
IL-2
TH1
TH1 or TH2?
IFN-γ
TH1
TH1 or TH2?
TNF-β
TH1
TH1 or TH2?
GM-CSF
TH1
TH1 or TH2?
IL-3
TH1 and TTH2
TH1 or TH2?
IL-4
TH2