Tolerance And Autoimmunity Flashcards
What is tolerance
A state of immune non-responsiveness to self
Which mechanisms generate tolerance
Central tolerance
Peripheral tolerance
What does autoimmunity reflect
A loss of self tolerance
What does AIRE do
Modulate transcription of peripheral self antigens in the thymus
How are T cells kept tolerant
Deletion
Maintenance of immunologic ignorance
Functional inactivation (anergy)
Suppression
What does CTLA-4 bind to
B7 on APC
What does CTLA-4 do
Serve as a negative regulator of T cell activation and proliferation
What does PD-1 do
Influence central and peripheral tolerance mechanisms
What features of protein antigens can favour tolerance over an immune response
Persistence
Location
Presence of adjuvant
Characteristics of APCs
What do regulatory T cells do in tolerance
Suppress immune responses and maintain self tolerance
What does TGF-b stimulate the expression of
Foxp3
What does IL-2 do to T cells
Promotes differentiation of T cells into regulatory cells
What % of thymocytes that develop in the thymus die in there from apoptosis
98%
What are the classes of self antigens
Cell surface antigens
Intracellular antigens
Soluble antigens
What does IL-10 inhibit
Production of IL-12 by activated macrophages and DC’s
Expression of co stimulators & MHC class II
Where does B cell tolerance take place
Bone marrow
What is B cell tolerance important for
Maintaining unresponsiveness to thymus-independent self antigens
What does PTPN22 encode
Lymphoid protein tyrosine phosphatase (Lyp)
