III - autoimmune disease Flashcards
what is a normal CD4 T cell response steps 1-3
antigen presenting cell recognises a pathogen
internalisation and antigen processing
peptide presented via MHC class II
normal CD4 T cell response steps 4-6
interaction of the TCR complex with the peptide
danger signal/co-stimulation
T cell proliferation/cytokine production
what do T cells signal to, to launch an immune response
B cells and CD8 T cells
what is tolerance
prevention of an immune response against a specific antigens
tolerant against self antigens
features and function of MHC
act as antigen presenting structure
partly determines response to antigen
implicated in susceptibility and development of autoimmune diseases
what is central tolerance
mature T cells in the thymus are tested to check their reactivity to self
if they react to self they are destroyed
negative selection
what happens to a T cell precursor
rearrangement of TCR genes
converted into an immature thymocyte
what receptors does an immature thymocyte present
CD8
CD4
CD3
TCR
what happens to immature thymocytes that do not interact with MHC
death by apoptosis
what happens to immature thymocytes that do not interact with MHC
death by apoptosis
what do thymocytes interact with
class I/II MHC molecules presented on epithelial cell
what thymocytes are negatively selected
thymocytes with high affinity for self-MHC or self-antigen
what is the difference in the development of a T-cell with low and intermediate affinity to self-antigen
low affinity - becomes a T cell
intermediate affinity - becomes a T regulatory cell
what is peripheral tolerance
deletion or anergy of lymphocytes
that recognize self antigens in
peripheral tissue
what may lead to anergy or inactivation
Lack of accessory signals in presence of TCR
engagement with MHC-peptide
