preventing and treating disease

• vaccine

  = a dead/inactive/weakened version of a pathogen or antigens.

  • injected into the blood stream- triggers primary response- memory cells made so if infected again= secondary response.
  • antigen presenting cell- antigen binds to specific B-lymphocytes
  • T-helper cells produce interleukins- clonal selection+ expansion
  • produces plasma cells- antibodies= primary immune response
  • memory cells remain in blood= secondary immune response.
• herd immunity 


  = when a significant number of people in the population have been vaccinated, this gives protection to those who don't have immunity.
• diseases with no vaccination

  -malaria= protist is very evasive- spends time inside erythrocytes so it's protected by self antigens from immune system- within an infected individual, it's antigens reshuffle.

  -HIV= enters macrophages and T-helper cells so it disables the immune system.
• penicillin

  =1st widely used effective, safe antibiotic capable of curing bacterial diseases.

  • comes from mould, found by Fleming
  • Florey+ Chain developed an industrial process for the drug
• drug using computer programs

  -they build up models of molecules in the body- pathogens and their antigen systems- allows models of potential drug molecules to be built up which are targeted at particular areas of a pathogen.

  • can isolate chemicals with any useful action against a group of a pathogen or against the mutated cells in a cancer.
• sources of medicine

  -penicillin= commercial extraction originally from mould on melons- antibiotic treatment for bacterial disease.

  -docetaxel= derived from yew trees- treatment of breast cancer.

  -asprin= from willow bark- painkiller, anti-inflammatory

  -prialt= venom of a cone snail- painkiller

  -vaacomycin= from soil fungus- antibiotic

  -digoxin= from foxgloves- heart drug to treat heart failure