23 - T cells V: Th17 cells Flashcards
-[p00TH17 cells – Type 3 response
Signal 3
TGF-b
IL-6
IL-23
TH17 cells – Type 3 response
Transcription factors
STAT 3 protein activated
TH17 cells – Type 3 response
Master transcriptional regulator
RORyT gene activated (also a TF)
TH17 cells – Type 3 response
Effector cytokines
IL-17
IL-22
TH17 cells – Type 3 response
Discovery
In 2005
-2003: IL-23 is important for autoimmunity
Rethink classic TH1 vs TH2 paradigm
TH17 cells – Type 3 response
Responses
Enhance neutrophil responses & mucosal immunity
-help respond to extracellular bacteria & fungi
Pro-inflammatory response & involved in autoimmune disorders
TH17 functions
Secrete IL-17 & IL-22 = stimulate other cells to secrete more cytokines/chemokines/antimicrobial peptides
Recruit neutrophils
Aid in targeting extracellular bacteria & fungi
IL-17
pro-inflammatory cytokine
TH17 response = involved in … examples:
inflammatory diseases (autoimmune diseases)
o Psoriasis
o Inflammatory Bowel disease
o Asthma
o Rheumatoid arthritis
o Multiple sclerosis
TH17 effector functions (6)
-Aid in targeting extracellular bacteria & fungi
-Induce production of antimicrobial peptides
-Increase epithelial turnover
-Induces other cells to produce G-CSF
-Induce other cells to secrete chemokines
-Attracts more TH17 cells
TH17 effector functions
Induce production of antimicrobial peptides
o IL-17 & IL-22 induce epithelial cells – produce antimicrobial peptides
o Contribute to killing/slowing replication of bacteria
TH17 effector functions
Increase epithelial turnover
o IL-22 increases division & shedding of epithelial cells
o Hinder bacterial growth
TH17 effector functions
Induces other cells to produce G-CSF
o Il-17 acts I stromal & myeloid cell = secrete G-CSF
o G-CSF enters circulation & target bone marrow precursors to differentiate into neutrophils
TH17 effector functions
Induce other cells to secrete chemokines
o IL-17 act on stromal & epithelial cells – secrete chemokines
o Chemokines attract neutrophils
-Phagocytosis
-Form NETs
-Release granules – can kill bacteria & fungi
TH17 effector functions
Attracts more TH17 cells
o TH17 cells secrete chemokine – recruit additional TH17 cells
IL-17 – induce
macrophage to secrete pro-inflammatory cytokines
-IL-1b & TNF-a
TH17 cells have several
different pro-inflammatory effects
Monoclonal antibody
antibody produced by single clone of B lymphocytes – all identical
-Bind specifically to target to activated or inhibit its activity
Involved in response against parasitic helminths
TH1 or TH2 or TH17 orEffector CTL
TH2
Can directly activate macrophages to produce reactive oxygen species
TH1 or TH2 or TH17 orEffector CTL
TH1
Recognize antigen presented on MHC I
TH1 or TH2 or TH17 orEffector CTL
Effector CTL
Involved in response against extracellular bacteria & fungi
TH1 or TH2 or TH17 orEffector CTL
TH17
ILC activated by
cytokines
Different group target
different pathogens
ILC2 & TH2 cells produce cytokines
generate…
IL-4, IL-5, IL-13
Generate IgE & degranulation of granulocytes & other functions
ILC3 cooperate with
TH17 & produce IL-17 to defend against bacterial infection
TH17 Response to:
extracellular bacteria & fungi
Th17 function:
Induce production of anti-microbial peptides from epithelial cells
Promote turnover of epithelial cells
Induce stromal & myeloid cells to produce G-CSF = promote production of neutrophils
Induce other cells to secrete chemokines = recruit neutrophils
Attract more TH17 cells
Induce macrophages to secrete pro-inflammatory cytokines
TH17 cells also have role in
autoimmunity
