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
what do T regulatory cells induce an inhibitory response in
Ag
what happens if IgM is cross linked with an immature B cell
causes cell death
which immature B cells are not allowed to mature
ones with no strong reactivity to self-antigens
If Ag receptor is cross linked in the bone marrow - apoptosis
what is pernicious anemia
auto-antibodies against membrane bound intestinal proteins on gastric parietal cells
what does the thyroid convert tyrosine into
T4 - thyroxine
T3 - triiodothyromine
function of T4/3
regulation of basal metabolism and protein synthesis
what is hashimoto’s thyroiditis and how does it affect the thyroid
auto-reactive antibodies and T cells that attack the thyroid
inflammation, larger thyroid, destruction of thyroid follicles
what blocks antibodies in hashimoto’s thyroiditis
TSH
thyroid peroxidase
thyroglobulin
what is Grave’s diseases
unregulated overproduction of thyroid hormones
what are the antibodies produced by Grave’s disease
long-acting thyroid-stimulating antibodies (LATS)
increases metabolic rate by 60-100%
what are the symptoms of Grave’s disease
anxiety, irregular heartbeat, fatigue, tremor, exophthalmos
what is systemic lupus erythematosus and symptoms
systemic autoimmune disease that attacks many tissues
fever, arthritis, skin rash, pleurisy, kidney dysfunction
how does LSE effect the kidney
auto-antibodies bind to basement membrane in glomerulus
results in immune-driven inflammation
what is multiple sclerosis
auto-antibodies attacks myelin
causes inflammation
what are the possible causes of autoimmune diseases
release of sequestered antigen
molecular mimicry
inappropriate activation of MHC class II
polyclonal activation of B cells
