Immunology

Vaccination
1. Features of a successful vaccination program
  1. Few side-effects
  2. Means of producing, storing and transporting available
  3. Means of administering vaccine available
  4. All vulnerable population vaccinated
2. Problems with controlling cholera
  1. Intestinal disease- not easily reached by immune system
  2. Antigenic variability
  3. Mobile populations spread cholera
3. Principles
  1. Weakened/mutated pathogen injected
    1. Stimulates immune response and production of antibodies
      1. Immunological memory - faster response to future infections
4. Ethics
  1. Use of animals in development of vaccines
  2. Could have side-effects/cause disease
  3. Human trials
5. Problems with controlling TB
  1. HIV - more people with impaired immune systems
  2. Body kills bacterium before antibodies produced
  3. Ageing populations - older people have weaker immune systems
Antibodies
1. Proteins synthesised by B cells
2. Quaternary structure: two heavy chains and two light chains
  1. Held together by disulfide bonds
3. Variable and constant regions
  1. Antigen-binding sites: antigen-antibody complex is formed
4. Monoclonal antibodies: produced from a single clone of B cells
  1. Formed by hybridisation with cancer cells
  2. Number of useful functions
    1. Immunoassay (e.g. pregnancy testing kits)
    2. Cancer treatment
    3. Transplant surgery
B cells and cell-mediated immunity
1. 1. B cells take up suface antigens of pathogens and present them on the membrane
2. 2. Activated T helper cells bind to antigens and activate the B cells
3. 3.B cells divide by mitosis and specialise into one of two types of cells:
  1. Plasma cells produce antibodies.
    1. Agglutination (clumping) of pathogens facilitates phagocytosis
    2. Cause lysis of pathogens
  2. Memory cells store an immunological memory of the antigen.
    1. Secondary immune response: greater and faster antibody production
Phagocytosis: the non-specific immune response
1. 1. Macrophage attracted to pathogen by chemoattractants
2. 2. Macrophage binds to pathogen and engulfs it, forming a phagosome
3. 3. Lysosome fuses with phagosome to form a phagolysosome
4. 4. Digestive enzymes break down the pathogen
T cells and cell-mediated immunity
1. T cells mature in the thymus gland.
2. T cells carry out cell-mediated immunity:
  1. 1. Pathogens invade body/ingested by phagocytes
    1. 2. Phagocyte presents antigens on its cell membrane
      1. 3. T cells have complementary receptors which bind to the antigens
        4. The T cell then divides rapidly by mitosis.
3. Roles of cloned T cells
  1. Developing into memory cells for faster secondary response
  2. Stimulating phagocytosis
  3. Producing interleukins, which stimulating B cells to divide
  4. Killing infected cells
    1. Perforin makes holes in cell membrane of infected cells - they become freely permeable and die

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Immunology

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	Created by Stephen Cole about 10 years ago