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INNATE IMMUNITY includes what?
- Physical Barriers
- Cellular Barriers
- Chemical Barriers
What are the Features of Innate Immunity?
- First Line of Defense
- Present on Birth
- Resistance not improved by repeated infections
- Physiological Barriers
- Phagocytosis, Inflammation, Fever
What are the characteristics of the Adaptive/Acquired Immunity?
- Resistance improves after repeated infections
- Cells involved include B lymphocytes, T lymphocytes and Macrophages
- Primary and secondary lymphoid organs are involved in the process
What is an IMMUNOGEN?
Any agent inducing an immune response
What are the characteristics of an immunogen?
- High Molecular Weight
- Chemical Complexity
What is an Antigen?
Any agent capable of binding specifically to components of immune response
What are the antigens composed of?
- Nucleic Acids
What are Antibodies?
Soluble globulin proteins
What are the characteristics of antibodies?
- Distinct biological activity
- Four chain structure: two identical light and two identical heavy chains
- Three fragments of equal sizes
- Fab fragment
- Fc fragment
What are the Functions of IgG?
- Agglutination , precipitation and opsonisation
- Conferral of immunity to fetus
- Activation of complement
- Neutralization of toxins and viruses
- Immobilization of bacteria
What are the Properties of IgM?
- Pentamer molecule
- Synthesized after immunization
- Elevated levels levels indicate recent infection
- Synthesized by placenta and elevated levels in fetus indicative of congenital infection
- Best agglutinating and complement-activating antibody
What are the properties/functions of IgA?
- Major immunoglobulin in secretions
- Monomeric as well as Diameric
- Role in Mucosal infections
- Bactericidal Activity
- Antiviral Activity
What are the properties/functions of IgD?
- Causes the differentiation of B cells to a more mature form
- Present on the surface of B lymphocytes
- Present in monomeric form
What are the properties/functions of IgE?
- Reaginic antibody
- Protects against parasites
- Important role in hypersensitivity
How do Primary and Secondary Antibody Responses differ?
- Time course; secondary response has a shorter lag phase and an extended plateau and decline
- Antibody titer: greater in secondary response
What are the LYMPHOID CELLS?
- T cells: develop in the thymus
- B cells: differentiate in fetal liver and adult bone marrow
- NK cells: does not possess T cell or B cell receptors
What are the characteristics of T Cells?
- The definitive T cell marker is the cell antigen receptor (TCR)
- TCR-1 (Composed of ϒ and Ϭ chains, 5%)
- TCR-2 (Composed of α and β chains, 95%)
- Both receptors are associated with a complex of polypeptides making up the CD3 complex.
The TCR-2 cells are divided into two major subsets, what are they?
- CD4+ (Helper T cells)
- CD8+ (Cytotoxic T cells)
CD4+ (Helper T cells) TCR-2 cells are divided into what subgroups?
- CDw29+ (positively influence the immune response of T cells and B cells-the helper function)
- CD45R+ (Induce cytotoxic function in CD8+ cells)