INFLAMMATORY RESPONSE

INFLAMMATORY RESPONSE

1. STEP I

   • Pathogen invade the body and enter through the damaged tissue
     • The pathogen has foreign protein/polysaccharides that is immediately recognized by the immune system through Pathogen-Associated Molecular Patterns(PAMPs)

2. STEP II

   • When the invasion is detected, mast cells will secrete histamine
     • This causes the blood vessels to dilate and become more permeable, allowing more blood flow and white blood cells to accumulate
   • Histamine causes
     • Vasodilation
     • Increased vascular permeability

3. STEP III

   • Due to increased permeability of blood vessels, the monocytes & granulocytes can easily migrate to the injured area
     • This process is called diapedisis

4. STEP IV

   • The macrophages will also secretes cytokines
     • Main functions of cytokines are
       • immune cell proliferation
       • differentiation
     • Examples of cytokines
       • Interleukins (ILs)
       • Interferons (IFNs)
       • Tumor necrosis factors (TNF)
     • Cytokines will cause
       • Local effect
         • Inflammation
         • Tissue repair
         • Promote migration of WBC from blood vessels
       • Systemic effect
         • Fever
         • Leukocytosis— accumulation of WBC in blood vessels

5. STEP V

   • Once the macrophages recognizes the pathogen by PAMP, it will undergo phagocytosis

6. STEP IV

   • Complement proteins
     • Important complement protein: C3a
     • Needs the adaptive immune system to be activated first— by releasing antibodies
     • Functions
       • opsonization
         • Opsonization is a process whereby the pathogen is marked for destruction by a phagocyte. The antibody released by the adaptive immune system will bind to the epitopes of the antigen of the pathogen
       • pathogen lysis— by Membrane Attack Complex (MAC)
         • Membrane Attack Complex causes cytolysis— the pathogen will burst
         • The circular membrane attack complex acts as a channel which excess water moves into the cytoplasm
       • activation of inflammatory response
       • clearance of immune complexes