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Regulatory T Cells
Regulatory T Cells
12
Immunology
09/13/2012

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Term
Regulatory T (TReg) cells are ...
Definition
specialized CD4+ T cells.
Term
Function of Tregs is to 
Definition
maintain self-tolerance and immune homeostasis by suppressing the activation, proliferation, and effector functions of various immune cells.
Term
Where exactly do Tregs generate?
Definition

i) thymus

ii) periphery

Term
T/F Are Thymically-derived CD4+CD25+Foxp3+ TReg cells  a relatively homogeneous population?
Definition
True
Term
What is the change in thymically-derived CD4+CD25+Foxp3+ TReg cells when they migrate to periphery?
Definition
A subpopulation of these cells  develop phenotypic characteristics similar to conventional memory and effector T cells.
Term
How does this phenotypic change helps?
Definition
Enables their subsequent migration to lymphoid and non-lymphoid tissues to maintain proper immune homeostasis.
Term
Except for the greek word ήλιος (sun), what is Helios in the immune cells.
Definition
Is a member of the Ikaros transcription factor family and it is preferentially expressed at the mRNA level by regulatory T cells.
Term
Helios is expressed uniquely in human FOXP3+ Tregs and distinguishes...
Definition
the thymic over the peripheral derived Tregs.
Term
 Members of secreted TReg  cytokine expression are:
Definition

i) IL-10

ii) TGF-β

iii) IL-35

Term
Role of IL-10 during TReg  differentiation.
Definition

i) Inhibits cytokine production by T cells, macrophages and dendritic cells

ii) Suppresses TH1/2 cell proliferation via inhibition of IL-2

iii) Down regulates MHC class II on monocytes, impairing antigen presentation for proper activation of T cells

Term
Role of IL-35 during TReg differentiation
Definition
Enhances TReg proliferation and IL-10 expression, while suppressing the development of TH17 and TH1 activated T cells
Term
Role of TGF-β during TReg differentiation
Definition

i) Inhibits IL-1- and IL-2-dependent T cell proliferation

ii) Inhibits activation of both T helper and cytotoxic T cells

iii) Inhibits the secretion of IFNγ, TNFα and other interleukins

iv) Downregulates the expression of cytokine receptors on activated T cells

v) Inhibits the proliferation of macrophages and monocytes and limits their production of reactive oxygen and nitrogen species

vi) Induces Foxp3 expression.