Immunology of the Endocrine System Flashcards
What is autoimmuinity?
An immune response against an antigen made by the body
Are the majority of autoimmune conditions more common in male or females?
Females
Which autoimmune condition is more common in men?
Ankylosing spondylitis
What is immunological tolerance?
Unresponsiveness to an antigen that the body has had previous exposure to
What name is given to the antigens that induce tolerance?
Tolerogens
What is self-tolerance and why is it important?
Tolerance to the self-antigens
Failure of this tolerance leads to autoimmune disease
To avoid autoimmune disease, what happens to the B and T cells?
The B and T cells bearing these self-reactive molecules are either eliminated and downregulated so the immune system is made specifically tolerant to self-antigens
Which part of the body plays an important role in eliminating the T cells that have a high affinity for self-antigens?
Thymus
Which part of the body plays an important role in B cell tolerance?
Bone marrow
Some cells escape the central tolerance and escape to the periphery. However, there is peripheral tolerance in place. What is meant by peripheral tolerance?
Mature lymphocytes that recognise self antigens in peripheral tissues become incapable of activation by re-exposure
Or, the cell die by apoptosis
Which mechanism induces peripheral tolerance?
Second signals
-> this is antigen recognition without co-stimulation
How is peripheral tolerance maintained by regulatory T cells?
These T cells supress the activation of lymphocytes specific for self and other antigens
Some self antigens are sequestered from the immune system.
What can act as barriers for these self-antigens?
Anatomic barriers, specifically in the CNS, testes and eyes
-> these cannot engage antigen receptors
Name three mechanisms of peripheral tolerance.
Anergy
Treg suppression
Deletion- cell death
->the cell death is of the lymphocytes when they recognise the antigens
(?idk gal soz)
Treg?
Regulatory T cells
When does anergy occur?
In the absence of co-stimulation
What happens in autoimmune disease which allows the cells to attack self-antigens?
Overcoming of peripheral tolerance
Why may autoimmune overcoming of peripheral intolerance occur?
-Inappropriate access of self-antigens
-Inappropriate/increased local expression of co-stimulatory molecules
-Alterations in the way these self-antigens are presented to the immune system
Why is autoimmune disease more likely to occur when there is inflammation of tissue damage present?
There will be increased activity of proteolytic enzymes, causing intra and extracellular proteins to be broken down.
Therefore, there are higher concentrations of peptides being presented to the responsive T cells.
How may the structures of self-peptides be altered?
Viruses
Free radicals
Ionising radiation
-> therefore, by changing structure, they bypass previously established tolerance
Is there a genetic disposition to autoimmune disease?
Yes
->if someone in the family has an autoimmune condition, they themselves are more likely to develop another condition but more likely their family will also develop some sort of autoimmune disease
What % of the population have some sort of autoimmune disease
3%
The peak years of onset for autoimmune conditions is 15-65yrs.
Which autoimmune condition is the exception to this?
Type 1 diabetes
->often occurs at an earlier age
Non-organ specific organ diseases can affect multiple organs. Why is this?
Associated with autoimmune responses against self-molecules. These self-molecules are widely distributed by the body, hence why affects multiple organs
