Immune response

Immune response

1. Adaptive immune system

   • Humoral immunity (B lymphocytes)
     • Involve with extracellular microbes
     • Proposed by:
       • Paul Erlich
     • B lymphocytes
       • Derived from: lymphoid stem cell
       • Mature at: Bone marrow
       • Activated by helper T cells (Th2)
       • Possess (significant d):
         • IgM
         • MHC class II
         • CD18+CD11a = LFA-1
           • It is a integrin adhesion protein
         • CD54 (ICAM-1)
           • adhesion molecule: binding B cells to other cell types
   • Cell-mediated immunity (T lymphocytes)
     • T lymphocytes
       • 2 pathways
         • Cytotoxic T cells (35%) (CD8+)
           • Functions
             • 1) Recognises viral peptide + MHC-I
             • 2) Kills the infected cell
           • involve with intracellular microbes (virus)
         • Helper T cells (65%) (CD4+)
           • Functions
             • Th1
               • 1) Recognise bacterial peptide + MHC-II
               • 3) Activates macrophages
               • 2) Release cytokines; IFN--ɣ
                 • inhibits Th2 proliferation
             • Th2
               • 1) Recognise antigenic peptide + MHC-II
               • 3) Activates B cell / Mast cells / Eosinophil
               • Release IL-10 that inhibits Th1production
               • 2) Release IL4, IL5, IL6 and TGF-β
       • Activated by:
         • MHC-I
         • MHC-II
         • Other signals, i.e.CD28-80/86
       • Possess: T cell receptor + CD3 = TCR complex
       • Origin: Thymus
       • Mature at: Bone marrow
       • Proposed by:
         • Eli Metchnikoff

2. Innate immune system

   • Function
     • Express receptors on the surface
     • Able to detect infectious microorganisms
   • Derived from
     • Pleuripotent hemalopoletic stem cell
       • Myeloid stem cell
         • Dendritic cells
         • Monocytes
         • Neutrophils
         • Eosinophils
         • Mast cells
         • Basophils
         • Platelet
         • Erythrocytes