Innate Immunity

Innate Immunity

1. First Line of Defense

   • Physical barrier
     • Skin
       • Skin form waterproof mechanical barrier
         • Prevent entry of microbes
     • Mucus lining
       • Trap dirt and microbes
   • Chemical barrier
     • Saliva
       • Contain enzyme that breaks down the cell wall of bacteria
     • Stomach acid
       • Has low pH acid that kills bacteria and parasites
     • Tears
       • Contain enzyme that breaks down the cell wall of bacteria

2. Second Line of Defense

   • Group of cells, tissues and organs that work together
     • To protect the body
   • It create hostile environment for the invaders
   • It has four components
     • Fever
       • The body temperature increase to 37 C and above
         • It initiated by pyrogens
           • It change the settings of hypothalamus
       • Reduced iron availability
         • Iron-required pathogens cannot get the iron needed
       • Inhibition of microbial multiplication
         • Creating sub optimal temperature
       • Increase metabolic rate
         • Stimulates immune reactions
     • Inflammation
       • Symptoms
         • Redness
         • Heat
         • Pain
         • Oedema
       • Stages
         • Tissue injury
           • Dilation and increased leakiness
             • Phagocytes consume bacteria
               • Release of cytokines
                 • Causing vasodilation
     • Phagocytosis
       • Contain phagocytes
         • They possess lysosome containing substances
       • Stages
         • Attachment
           • Ingestion
             • Killing
               • Degradation
     • Antimicrobial proteins
       • Four main types
         • The complement system
           • Work in cascade reactions
           • Three pathways
             • Classical
             • Lectin
             • Alternative
         • Interferons
           • Involve cytokines to against virus
         • Iron-binding protein
           • Limit the growth of pathogens
           • Examples
             • Hemoglobin
             • Lactoferrin
             • Transferrin
         • Antimicrobial peptides
           • Kill bacteria by inserting them into the membrane

3. It is non-specific

4. Immune components are preformed

5. Response magnitude is similar during the first and subsequent encounters

6. No memory is stored