Acute Phase Proteins

Regulation

IL-6 released from T/B-cells, macrophage, keratinocyte, astrocyte, bone marrow stromal cell and others binds to receptors.

Gp130 protein undergoes conformational change and this activtates 2 paths:

• MAPK: NF-IL6 dimer formed, binds to type1 IL-6RE promoter for acute phase proteins
• STAT3: STAT3 dimer formed, binds to type 2 IL-6RE promoter for acute phase proteins

Types of Acute Phase Proteins

1. Complement (c5, c3) needed for all pathways of cascade to cause pagocyte recruitement and MAC which alters the cytoskeleton

2. Protinase inhibitors to prevent harmful action of neutrophils (cathepsin-G), mast cell (chymases) which can release oxidative agents which cause cell damage

Types of Acute Phase Proteins

3. Coagulation proteins such as firbinogen and thrombin as these are needed for clotting and preventing further infiltration of pathogens to cause further immune response and inflammation

4. Pentraxins such as the pattern recognition receptors ( C-reactive protein, serum amyloid P) activate classical pathway

5. Soluble pattern recognition receptors such as mannose-binding lectin which activates the lectin pathway of the complement cascade

6. Transport proteins: haptoglobin (prevents harmful products from haemoglobin oxidation from causing damage to cells such as necrosis and thus elciting inflammation) and ferritin