Lecture 11- Autoimmunity Flashcards
What are the four key mechanosms of tolerance?
Clonal Deletion, Clonal Anergy, Immunological ignorance, Supressor Cells
How does the immunological tolerance of clonal deletion work?
Self Reacted immune cells are detected in the primary lymphoid organs and deleted before they can be released
How does the immunological tolerance mechanism of Clonal anergy work?
Lack of ‘help’ signal via a costimulation molecule results in the cell becoming anergic and dying
What is the mechanism of immunological ignorance?
A self reactive B cell is never activated as there is no specific t Cell for it, or T Cells are sequestered as they are contained in regions such as the eye resulting in them never encountering the self antigen they are specific for
What is the mechanism of supressor cells?
Self reacting lymphocytes are kept in check by supressor t cells
Are autoantibodies typically produced?
Yes, in small amounts as they can help to regulate immune responses, these are low affinity autoantibodies, as high affinity ones will cause disease
What are the 3 mechanisms through which injury or infection can cause autoimmune disease?
Molecular Mimicry, Release of sequestered antigens, Polyclonal activation
What is molecular mimicry?
When a pathogen contains antignes that have a similar molecular shape to self atnigens resulting in cross reactions
What is polyclonal activation with regards to autoimmune disease?
Superantigens activate large populations of lymphocytes which may include those that are self reactive
What causes organ-specific autoimmune disease?
When the autoreactive lymphocytes are targeted by proteins only found in a specific organ
What role might Toll-like-receptors play in autoimmune disease?
They could potentially be reactive to self antigens, as those with reduced numbers of TLRs are more resistant to autoimmune disease
What is the key role of Toll-Like-receptors?
To recognise common patterns of pathogens to allow for an innate immune response and to trigger signalling for cytokines, costimulatory molecules via transcription facotr NF(Kappa)B
What does TLR-4 recognise?
Lipopolysaccharide
What does TLR-2 recognise?
Peptidoglycans
