Chap 5

• Immunity


  Protection from infectious disease, usually indicated by the presence of antibodies, very specific to a single organism

  
• Immunization


  Process of inducing immune response, humoral or cell mediated

  
• Vaccination


  Process of inoculating the vaccine or the antigen

  
• Passive immunity


  1. Transfer of maternal antibodies through placenta

  2. Transfer of maternal antibodies through milk

  3. Following administration of immunoglobulin or antiserum

  
• Active immunity


  1. Following clinical infection

  2. Following subclinical infection

  3. Following vaccination

  
• Active immunity


  Developed in response to stimulus by an antigen (infecting agent or vaccine) and is characterized by the production of antibodies by the host

  
• Passive immunity


  Immunity conferred by an antibody produced in another host, the body's immune system is not activated

  
• Immunizing agents


  • Vaccines
  • Antisera
  • Immunoglobulins

  
• Immunoglobulins


  Two types: normal human immunoglobulin and specific (hyper-immune) human immunoglobulin
• Antisera


  Materials prepared in animals or non human sources such as horses
• Vaccination


  Method of giving antigen to stimulate the immune response through active immunization

  
• Vaccine


  Immunogenic but not pathogenic substance designed to produce specific protection against a given disease

  
• How vaccination works


  1. Expose the patient to an antigen

  2. A live or inactivated substance derived from a pathogen capable of producing an immune response

  3. If the patient is subsequently exposed to virus carrying this antigen they will mount a faster immune response

  
• Types of vaccines


  • Live vaccines
  • Attenuated live vaccines
  • Inactivated (killed) vaccines
  • Toxoids
  • Polysaccharide and polypeptide (cellular fraction) vaccines
  • Recombinant vaccines

  
• Live vaccines


  Made from live infectious agents without any amendment

  
• Live attenuated (avirulent) vaccines


  Virulent pathogenic organisms are treated to become attenuated and avirulent but immunogenic

  
• Inactivated (killed) vaccines


  Organisms are killed or inactivated by heat or chemicals but remain immunogenic, usually safe but less effective than live attenuated vaccines

  
• Toxoids


  Prepared by detoxifying the exotoxins of some bacteria rendering them immunogenic but not pathogenic, adjuvant is used to increase the potency
• Polysaccharide and polypeptide (cellular fraction) vaccines


  Prepared from extracted cellular fractions, e.g. meningococcal vaccine from the polysaccharide antigen of the cell wall, pneumococcal vaccine from the polysaccharide contained in the capsule of the organism

  
• Recombinant vaccines


  Produced by genetic engineering technology, prepared by insertion of a segment of the respective viral gene into the gene a yeast cell or virus

  
• Routes of administration


  • Deep subcutaneous or intramuscular route (most vaccines)
  • Oral route (sabine vaccine, oral BCG vaccine)
  • Intradermal route (BCG vaccine)
  • Scarification (small pox vaccine)
  • Intranasal route (live attenuated influenza vaccine)

  
• Scheme of immunization


  1. Primary vaccination

  2. Booster vaccination
• Side-effects of vaccines


  • Localized hypersensitivity at site of infection
  • Fever
  • Contracting encephalitis after a vaccination against measles
  • Mutation of attenuated microorganisms → virulent → disease
  • Allergy reaction to vaccine's medium

  
• Immunization is the process whereby a person is made immune or resistant to an infectious disease, typically by the administration of a vaccine

  
• Vaccines stimulate the body's own immune system to protect the person against subsequent infection or disease

  
• Immunization is a proven tool for controlling and eliminating life-threatening infectious diseases