Autoimmunity (Exam 3) Flashcards
What is autoimmunity?
inflammatory response to self-antigen (from failure of self-tolerance)
When is an autoimmunity disease systemic?
if self-reactive lymphocytes are circulating or if self-antigen is everywhere
Which autoimmune disease has circulating self-nucleoprotein + antibody immune complexes which leads to the systemic disease?
lupus
How are autoimmune diseases organ-specific?
antigens are restricted to specific locations
Give two examples of organ-specific autoimmune diseases.
diabetes (insulin in pancreas)
arthritis (collagen in joints)
(T/F) There is a strong genetic component to autoimmune disease.
True
Higher risk of autoimmune disease is associated with complex _______ traits.
polygenic
How do viral or bacterial infections affect autoimmunity?
can trigger it or worsen it
What two mechanisms can infection use to trigger autoimmunity?
- bystander activation
- molecular mimicry
How does bystander activation via infection cause autoimmunity?
infection –> inflammation –> APCs activate self-reactive T cells
What is molecular mimicry?
when microbe has antigen similar to self-antigen –> activates self-reactive T cells (to cause autoimmunity)
Autoimmune reactions can worsen by amplification of the response through ___________.
epitope spreading
What is epitope spreading?
self-reactive T cells respond to antigen –> tissue injury –> amplifies self-reactive T cells
Match whether an AIRE, CTLA4, FoxP3, or Fas receptor defect causes each autoimmunity mechanism:
- failure of T cell anergy; reduced threshold to activate self-reactive T cells
- failure of apoptosis for self-reactive lymphocytes
- decreased regulatory T cell function
- decreased self-antigen in thymus –> defective negative selection
- CTLA4
- Fas
- FoxP3
- AIRE
