Bio 8A

Question 1

what are the types of immunity?

Answer 1

natural immunity
- protection against a disease formed without medical intervention

artificial immunity
- immunity that has been developed via medical intervention
- Humoral response
- Artificially acquired active immunity is formed after vaccination

active immunity
- protection against a disease created by antibodies and memory cells formed by a person’s own adaptive immune system

passive immunity
- protection against a disease created by antibodies from an external source

Question 2

what is natural active immunity?

Answer 2

• an individual’s own immune system encounters a pathogen and mounts a response against it
  
  • creates antibodies and memory cells specific to the pathogen

Question 3

what is natural passive immunity?

Answer 3

• an individual acquires antibodies from a ‘natural’, non-medical external source
  • breastfeeding
    
    • contains antibodies generated from the mother’s own immune system - once absorbed by the baby’s bloodstream, it protects them against pathogens)
  • placenta
    
    • antibodies produced by the mother are able to cross the placenta and enter the foetus’ bloodstream via the umbilical cord - protects the child during pregnancy and after it is born for a short period of time (helps compensate for their weak immune system)

Question 4

what is artificial active immunity?

Answer 4

• an individual’s own adaptive immune system produces antibodies and memory cells due to medical intervention
  • vaccinations
    
    • medical treatment containing antigens designed to create immunity to a pathogen without causing actual disease
    • Vaccination programs (series of vaccinations designed to create long-term immunity) vary depending on the type of vaccine being used + the disease being prevented
      
      • Booster vaccines - given to a person later in time to enhance their existing immunity against a disease (memory and B cells die after a long time) as they generate more antibodies and memory cells to restore immunity

Question 5

what is artificial passive immunity?

Answer 5

• an individual acquires antibodies from an external source via medical intervention (injection or fusion)
  
  • the body does not develop active immunity as the antibodies they receive will not trigger the production of the memory cells
• antibody treatment immediately increases the number of antibodies in the blood
  
  • over time the antibodies degrade until they’ve all disappeared and the immunity they’ve created disappears
    e.g.
• antivenom
  
  • contains antibodies designed to neutralise venom

Question 6

what entails the immune response in according to vaccinations?

Answer 6

• a part of artificial active immunity
• primary immune response
  
  • First vaccination: The reaction of the adaptive immune system to an antigen it has not been previously exposed to
    
    • Delay in the AIS - takes time for antigen-presenting cells to find T and B cells complementary to the vaccine’s antigen and for the process of clonal selection to occur)
• secondary immune response
  
  • Second vaccination: The heightened reaction of the AIS to an antigen it has previously been exposed to
    
    • Memory cells created by the first vaccine quickly recognise the antigen in the vaccine and mount a rapid, large secondary immune response

Question 7

what are some of the issues with antibody transfer?

Answer 7

Rhesus (Rh) incompatibility
- different proteins found on the surface of red blood cells
- Rh+ = has the protein
- Rh- = does not have the protein

Question 8

what is herd immunity?

Answer 8

• it refers to immunity to an infectious disease at a population level
  
  • Achieved when the majority of people in a community are immune to a particular pathogen
    
    • Prevents the spread of pathogen to those who haven’t been vaccinated or haven’t already been infected with the pathogen (more unlikely to come into contact with a person harbouring the pathogen)