Lecture 24 Flashcards
What cytokines are associated with TH17’s signal 3
TGF-beta, IL-6, and IL-23
Which effector cytokines are associated with TH17 cells
IL-17 and IL-22
What master transcriptional regulator is associated with TH17
ROR-gammaT
Overall functions of TH17
1) Enhances neutrophil responses and mucosal immunity, helps respond to extracellular bacteria and fungi
2) Pro-inflammatory response and involved in many autoimmune disorders
TH17 transcription pathway
TGf-beta, IL-6, IL-23 (signal 3)–>activates STAT 3 (transcription factor)–> RORgammaT gene gets activated (master transcriptional regulator)–>IL-17 and IL-22 secretion
TH17 functions
1) Secretes IL-17 and IL-22 (stimulates other cells to secrete more cytokines, chemokines, and antimicrobial peptides)
2) Recruits neutrophils
3) Helps in targeting extracellular bacteria and fungi
What kind of cytokine is IL-17
IL-17 is a pro-inflammatory cytokine
Which inflammatory diseases are TH17 responses involved in
Autoimmune and allergy
Examples;
Psoriasis, Inflammatory bowel disease, Asthma, Rheumatoid arthritis, multiple sclerosis
How does Th17 induce production of antimicrobial peptides?
IL-17 and IL-22 can induce epithelial cells to produce antimicrobial peptides–>killing/slowing bacteria replication
What kind of response is TH17
TH17 is a Type 3 response to infection
TH17 effector functions
1) Induce production of antimicrobial peptides
2) Increase epithelial turnover
3) Induce other cells to produce G-CSF
4) Induce other cells to secrete chemokines
5) Attracts more TH17 cells
How does TH17 increase epithelial turnover
IL-22 increases division and shedding of epithelial cells–>hindering bacterial growth
How does TH17 induce other cells to produce G-CSF
IL-17 acts on stromal and myeloid cell (both secrete G-CSF)
G-CSF enters circulation–>targets bone marrow precursors to–>differentiate into neutrophils
How does TH17 induce other cells to secrete chemokines
IL-17 acts on stromal and epithelial cells (both also secrete chemokines)
Chemokines will attract neutrophils which will then work through phagocytosis, forming NETs, release granules to kill bacteria and fungi
How does TH17 attract more TH17 cells
TH17 cells secrete a chemokine that recruits more TH17 cells
