Lecture 12 - Differentiation and Functions of CD4+ T Cells Flashcards
What signature cytokine(s) do Th1 cells produce?
L12 S19
-IFN-γ
What signature cytokine(s) do Th2 cells produce?
L12 S19
- IL-4
- IL-5
- IL-13
What signature cytokine(s) do Th17 cells produce?
L12 S19
- IL-17A
- IL-17F
- IL-22
What cytokines are produced by T cells and what are their functions?
IL-2, IL-4, IL-5, IL-13, IL-17, IL-21, IL-22, IFN-γ, and TGF-β
L12 S20
IL-2: T cell proliferation/survival
IL-4: B cell Ig switching to IgE
IL-5: activation of eosinophils
IL-13: B cell Ig switching to IgE; asthma
IL-17: stimulates acute inflammation
IL-21: autocrine amplification of Th17, affinity maturation and isotype switching of B cells
IL-22: maintenance of epithelial barrier function
IFN-γ: activates macrophages
TGF-β: inhibition of Th1/2 cell activation
What cytokines stimulate Th1 differentiation and what transcription factors do they activate?
L12 S21
Cytokines:
- IL-12 (DCs)
- IFN-γ (NK cells)
Transcription factors:
- T-bet (IL-12)
- STAT4 (IL-12)
- STAT1 (IFN-γ)
What cytokines stimulate Th2 differentiation and what transcription factors do they activate?
L12 S21
Cytokines:
-IL-4 (CD4+ T cell, mast cell, eosinophil)
Transcription factors:
- GATA-3
- STAT6
What cytokines stimulate Th17 differentiation and what transcription factors do they activate?
L12 S21
Cytokines (all from DCs):
- IL-1
- IL-6
- IL-23
- TGF-β
Transcription factors:
- RORγt
- STAT3
What transcription factor is responsible for development of T(reg) cells?
L12 S28
FOXP3
What are the signals required for the classical activation pathway of Mφ and what are the responses of a classically activated Mφ (M1)?
L12 S31
Signal 1:
-IFN-γ from Th1 cell
Signal 2:
-binding of CD40L (stimulated by antigen presentation to CD4+ T cell) to constitutively expressed CD40 (Mφ)
Responses:
- killing of phagocytized bacteria
- increased expression of MHC and B7
- secretion of cytokines (TNF, IL-1, IL-12, and chemokines)
What are the signals required for the alternate activation pathway of Mφ and what are the responses of a alternately activated Mφ (M2)?
L12 S32
Cytokines:
- IL-4
- IL-13
- both from Th2 cells
Responses:
- secretion of IL-10 and TGF-β
- inhibition of inflammation
- wound repair/scar tissue formation
How does IL-17/IL-22 ratio relate to Th17 cells function?
L12 S34
High IL-17/IL-22:
- stimulated
- stimulates inflammation, neutrophil response, and production of antimicrobial peptides
Low IL-17/IL-22:
- constitutive
- homeostasis
- increases barrier function and production of antimicrobial peptides
In what ways do CD4+ cells aid in activation of activation of CTLs?
What happens to CTLs in the absence of CD4+ cells?
L12 S35
Without CD4+ cells:
- APCs stimulate CTL activation through IL-15 (has same gamma-chain as IL-2)
- sub-optimally activates CTLs
With CD4+ cells:
- produce IL-2 which stimulates CTL activation
- produce IFN-γ to activate Mφ which then produce IL-12 that stimulates CTL activation
What are the traits of γδ T cells?
L12 S38
- Bridge gap between innate and adaptive immunity.
- Pre-activated phenotype that allows for rapid activation
- do not express CD4 or CD8
- immunoregulation
- present in intestine, uterus, and tongue
What are the the different sets of stimuli for γδ T cell activation?
L12 S41
- MHC-related and unrelated TCR ligands
- stress induced NKR ligands such as MHC class I polypeptide-related sequence A (MICA) that bind NKRs like NK group 2, member D (NKG2D)
- DAMPs and PAMPs that bind TLRs and Dectin-1
In what ways do γδ Τ cells act like part of both the adaptive and innate immune system?
L12 S43
Adaptive-like:
-rearrangement of TCR gene to produce large repertoire
Innate-like:
- restricted TCR acts like a PRR
- γδ TCR recognizes unpresented Ags
