Human Immune System

• The immune system defends the body against foreign substances and non-functional self cells
• Divisions of the immune system:

  1. Recognition + Response
  2. Innate + Adaptive/Acquired Immunity
  3. Humoral + Cellular responses
• Summary of Innate Immunity:

  
  

  Main components:

  • Physiological barriers (temp, low PH, chemical mediators)
  • receptor mediated processes (eg: Phagocytic/endocytic barriers
  • Inflammatory barriers
  • Very rapid (min/hr)

  
• Membrane attack complex (MAC) is a complex of proteins that are released from the cell during phagocytosis

  • They insert itself into a target cell membrane and form a channel (pore) causing cell lysis/cell death
• Adaptive Immunity Summary:

  Key Components:

  • Specific
  • Diverse (B cells, T cells)
  • Memory Cells
• T cells (T Lymphocytes)

  • Originate in bone marrow

  Structure:

  • Have unique antigen binding molecule that determine its function

  Function:

  1. Diverse: Th, Tc, Treg
  2. When encounter an antigen it stimulates rapid division, differentiation, memory T-cells and other effector T-cells
• B cells:

  • Mature in bone marrow
  • Unique in antigen-binding receptor

  Encounter antigen matching Ab leads tio:

  1. rapid division
  2. differentiation into memory B cells/Plasma cells that screte Ab

  
• Immunoglobulins (antibodies) Basic structure:

  • Composed of 4 polypeptide chains
  • ⤷ Two identical light chains, Two identical heavy )chains (isotopes

  
• Antibody-mediated effector functions [wip]

  • Abs do not kill pathogens just by binding onto them…