Transcript Chapter 16 Tolerance and Autoimmunity

Chapter 16 Tolerance and Autoimmunity
Tolerance –
a state of unresponsiveness to an antigen
1. Organ-specific autoimmune diseases:
Hishimoto’s thyroiditis – auto-Abs and sensitized TH1 cells
against thyroid Ags
Autoimmune anemias – auto-Abs against RBC Ags or other
factors
Goodpasture’s syndrome – auto-Abs against basement
membrane Ags
Insulin-dependent diabetes mellitus – auto-Abs against
pancreatic b cells
Graves’ disease – auto-Abs against receptors for thyroidstimulating hormone (TSH)
Myasthenia gravis – auto-Abs against acetylcholine receptor
2. Systemic autoimmune diseases
Systemic lupus erythematous – attacks many tissues
Multiple sclerosis – attacks the central nervous system
Rheumatoid arthritis – attacks joints
Proposed Mechanisms for
Induction of Autoimmunity
1. Release of sequestered antigens can induce
autoimmune disease.
2. Molecular mimicry may contribute to autoimmune
disease.
3. Inappropriate expression of class II MHC molecules
can sensitize autoreactive T cells.