INTRODUCTION TO IMMUNOLOGY

INTRODUCTION TO IMMUNOLOGY

1. COMPONENTS OF THE 'IS'

   • CARDIOVASCULAR SYSTEM
     • Heart and Blood
   • MONONUCLEAR PHAGOCYTE SYSTEM
     • Network of Reticular Fibres
     • Phagocytes (ESP macrophages)
   • LYMPHATIC SYSTEM
     • Organ of the Lymphatic System
       • PRIMARY LYMPHOID ORGANS -production sites of immune cells -maturation sites (absence of antigens)
         • Bone marrow
         • Thymus
       • SECONDARY LYMPHOID ORGANS -maturation sites for antigen-driven immune cells
         • Adenoid
         • Tonsils
         • Lymph nodes
         • Spleen
         • MALT
       • LYMPH CIRCULATORY SYSTEM
         • Lymphatic vessels

2. CELLS OF THE 'IS'

   • Leukocytes
     • Have nuclei
     • Involved in phagocytosis, inflammation and adaptive immune response
   • Platelets
     • Do not have nuclei
     • Involved in inflammation and bloood clotting

3. INNNATE IMMUNITY

   • 2ND LINE OF DEFENCE (PHYSIOLOGICAL BARRIERS)
     • Fever
       • > 37 degree celcius
       • initiated by PYROGENS
       • BENEFITS
         • reduced iron availability
         • inhibition of microbial multiplication
         • increase metabolic rate
     • Inflammation
       • Symptoms
         • Redness ( increased RBC )
         • Heat ( increased blood flow )
         • Pain ( stimulation of nerve endings )
         • Oedema ( swelling )
       • Stages
         • 1. Tissue injury by release chemical signals (HISTAMINE) 2. Dilation and increased leakiness of local blood vesssels. 3. Phagocytes consume bacteria and cell debris
       • Release of cytokines
       • Vasodilation
     • Phagocytosis
       • 1. Attachment
       • 2. Ingestion
       • 3. Killing
       • 4. Degradation
     • Antimicrobial proteins
       • Complement System
         • 3 pathways : classical, lectin and alternative
       • Interferons
         • 3 major types : IFN-alpha, IFN-beta, IFN-gamma
       • Iron-binding Proteins
         • SIDESPHORES (to steal iron from host proteins)
       • Antimicrobial peptides
         • Eg. Bacteriocins, Defensins, Magainins, Protegrins
   • 1ST LINE OF DEFENCE (PHYSICAL BARRIERS)
     • Antibacterial defense eg. SALIVA and TEARS
     • Prevents entry eg. SKIN
     • Traps dirt and microbes eg. MUCUS LININGS
     • Low pH killls eg. STOMACH ACID