Type II Hypersensitivity
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Introduction
Production of IgM or IgG to cell surface antigens or extracellular matrix proteins.
Mechanism
"Neutralisation" blockade of receptors:
- Antibodies attach to receptors, which prevents other molecules attaching.
- For example in myasthenia gravis antibodies attach to acetylcholine receptors which in turn prevents acetylcholine from attaching to the receptor and thus muscle contraction of that cell does not occur.
Immunological attack on target cells, destroying them by (see diagram):
1. Antibody dependent cell cytotoxicity (ADCC)
2. Complement mediated lysis
- Self RBC antigen:
- Foreign RBC:
- Blood transfusion reaction
- Haemolytic disease of new born (Rhesus disease in humans and neonatal isoerythrolysis in foals and kittens)
- RBC parasite:
- Feline infectious anaemia (Mycoplasma haemofelis)
3. Phagocytosis
From Pathology
- Cytotoxic reaction
- IgG and IgM interaction with antigens bound to cellular membranes
- Often involves complement fixation -> cellular damage
- In skin - circulating antibody to proteins of desmosomes in intercellular areas along basement membranes at epidermal-dermal junction
- Includes:
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Originally funded by the RVC Jim Bee Award 2007 |