Vaccines disease and monoclonal antibodies

• state what a vaccine is ?

  A suspension of antigens that are intentionally put into the body to induce artificial active immunity.
• what are the two main types of vaccines

  Live attenuated

  inactivated
• Disadvantages of vaccines

  People can have poor responses (defective immune system)

  antigenic variation

  antigenic concealment - pathogens hide from the immune system by living inside cells
• What is active immunity 


  Active immunity occurs when an antigen enters the body triggering specific immune response (antibodies are produced)

  the body produces memory cells. Giving the person long term immunity.
• what are the two types of active immunity?

  natural - the body produces its own antibodies due to the individual becoming infected with a disease under normal circumstances

  artificial - forms the basis I of vaccination. involves inducing an immune response in an individual, without them suffering the symptoms of the disease.
• what is passive immunity ? 


  passive immunity is produced by the introduction of antibodies into individuals from an outside source. no memory cells are formed. therefore no locating immunity.
• what is herd immunity ?

  when a sufficiently large proportion of the population has been vaccinated making it difficult for the pathogen to spread.
• What are the ethics of using vaccines ?

  The production and use of vaccines raise the following problems/questions ?

  1. some side-effects may cause long-term harm
  2. the development of vaccines often uses animals
• how can HIV be transmitted ?

  HIV is a virus- viruses are unable to surface outside the human body. and can only be transmitted by direct exchange of bodily fluids such as:

  1. blood donation
  2. sharing needles
  3. from mother across the placenta
  4. from mother to child through breast milk.
• what is the structure of HIV?

  Two RNA strands

  proteins - reverse transcriptase

  a protein coat (capsid)

  viral envelope - derived fro the cell membrane of the host helper T cell that the particle escaped from

  attachment proteins
• describe the replication of HIV

  when the virus enters the bloodstream it infects lymphocytes - helper T cells.

  1. viral RNA enters the cell
  2. viral reverse transcriptase enzymes produce DNA copy of the viral RNA
  3. the DNA is inserted into the chromosomes of the cell
  4. HIV uses the host cells cellular machinery to make copies of itself
  5. the host cell bursts (cell lysis) releasing the viral particles.

  gradually the viruses reduce the number of helper T cells in the immune system

  • B cells are no longer activated
  • no antibodies are produced
• Why are antibiotics ineffective against viral diseases like AIDS

  Viruses are non-living

  viruses are particles and not cells therefore have no metabolism.