passive and active immunity

Question 1

what is passive immunity?

Answer 1

occurs when an individual is given antibodies that were produced by another organism

Question 2

what are the advantages and disadvantages of passive immunity?

Answer 2

advantage
- the immune response is much faster than a natural immune response because there is no delay in antibody production
disadvantage
- no memory B or T cells are produced. there is no immunological memory.

Question 3

what is natural passive immunity?

Answer 3

• occurs when a mother passes ready-made antibodies to her child
• via the placenta during the pregnancy and via breastmilk after birth
• maternal antibodies protect the baby while it develops its own adaptive immune system

Question 4

what is artificial passive immunity?

Answer 4

• occurs when ready-made antibodies are injected into the individual
• injections of antibodies is called an antiserum
• typically used during a highly virulent infection or for treating toxins such as snake venom.

Question 5

what is a haemolytic disease?

Answer 5

• rbc carry a number of antigens on their surface. people with the Rh factor on their rbc have the Rhesus positive blood type. those without Rh factor are Rhesus negative.
• rbc can pass between a baby and its mother via the placenta
• if a Rhesus negative mother is pregnant with a rhesus positive child, the mother’s immune system can detect the rhesus antigens on the baby’s blood. the mother’s immune system will develop antibodies against the baby
• to prevent this, mothers with rhesus negative blood types are given an antiserum of anti-Rh antibodies. these antibodies destroy any Rh factor antigens before the mother’s immune system has time to detect them.
• disadvantage; mother does not produce memory B or T cells, no immune response to the baby.

Question 6

what is active immunity?

Answer 6

• occurs when the body produces its own antibodies in response to a specific antigen
• advantage; memory B and T cells are produced, so immunity is long-lasting.
• disadvantage; the initial response is slower than with passive immunity to start the response

Question 7

what is natural active immunity?

Answer 7

• the result of normal cell-mediated and humoral responses to a pathogen. the immune responses produce memory B and T cells. These memory cells are also produced to provide immunological memory
• ensure a faster and stronger immune response during the repeated infection. prevents the disease from occurring again

Question 8

what is artificial active immunity?

Answer 8

• stimulates B and T cell responses without exposure to a harmful pathogen. antigens are typically injected into the individual in the form of a vaccine.
• vaccines can either contain live but weakened pathogens or dead pathogens. subunit vaccines only contain part of the pathogen sometimes just the isolated antigens
• the immune system responds to the vaccine as if it was the real pathogen. the immune system produces memory B and T cells that can recognise the real pathogen
• if a real infection occurs, the immune system will respond quickly so that the disease will not occur.
  advantages:
• the person can develop immunity without being exposed to dangerous pathogens
• mem B and T cells are produced for future real infections
• vaccination has successfully eliminated many dangerous diseases from some populations
  disadvantages:
• attenuated (weakened) vaccines can cause a mild form of the disease in immunocompromised people or even in some healthy ppl
• additional booster vaccination is required to achieve immunity.