Hypersensitivity and Autoimmunity Flashcards
What is Type I Hypersensitivity mediated by?
IgE (mast cells)
What does Type 1 Hypersensitivity cause?
An allergic reaction
What is Type II Hypersensitivity mediated by?
IgG and IgM- complement system
What is Type II Hypersensitivity?
When the body’s own antibodies bind to antigens on its own cells
What is Type III Hypersensitivity?
Antibodies clump together and form immune complexes. (Low concentration of antibodies, High concentration of Antigens)
What is Type IV Hypersensitivity mediated by?
CD4+ T helper cells
What is Type IV Hypersensitivity a reaction to?
A foreign Antigen
What is an early phase response?
Occurs within minutes.
What mediators are present in Early Phase response?
Preformed Mast Cell- histamine, heparin etc)
What mediators are present in Late Phase response?
Newly Synthesised Mediators- Prostaglandins, Leukotrienes, Eosinophils, Th2 cytokines
What happens in localised immune complex formation? (Type III)
Localised Inflammation, can be cleared away by macrophages
What happens in Systemic Immune complex formation? (Type III)
Complexes are deposited in tissues and organs.
What does organ specific autoimmune disease affect?
Organs such as the Thyroid, Stomach etc
What does non organ specific autoimmune disease affect?
Muscle, skin, joints etc
