types of immunity

natural active immunity

• when pathogen enters body for the first time, immune system responds by producing antibodies

• t cells and b cells are produced so if you meet the pathogen for 2nd time, immune system will recognise and destroy pathogen

natural passive immunity

• new born baby immune system cant make antibodies for first few months

• some antibodies cross over placenta from mother so it has some immunity to disease at birth

• first milk mammal mothers make is v high in antibodies

• infants gut allows these glycoproteins to pass into bloodstream without being digested

artificial passive immunity

• for potentially fatal diseases antibodies are formed in one individual then extracted and ingested into the bloodstream of another individual

• gives TEMPORARY IMMUNITY. eg tetanus caused by bacteria, people are injected with antibodies from horse blood

artificial active immunity

• immune system stimulated to make its own antibodies to a safe from of antigen (vaccine)

• eg covid 19 vaccine

steps of a vaccine for artificial active immunity

1. pathogen is made safe in a number of ways:

   1. Killed or inactive

   2. weak

   3. toxin molecule modified

2. small amounts of safe antigen injected into blood

3. primary immune response is triggered by foreign antigens and body produces antibodies + memory cells as if you were injected with a live pathogen

4. if you come into contact with the pathogen again the secondary immune response is triggered and you destroy the pathogen