In this IBDP Biology post, we will be looking at how pathogens are destroyed, and how vaccines prevent the creation of diseases, let's get to it!
Antibodies
Antibodies: (Immunoglobins) Y shaped protein produced mainly by plasma cells
Antibodies aid in the destruction of pathogens:
- Opsonization: Make pathogen more recognizable to phagocytes so pathogen is more readily engulfed. Once bound they link the pathogen to the phagocyte
- Neurtalization of viruses and bacteria: Prevent viruses from docking to host cells
- Neutralization of toxins: Bind to toxins produced by antibodies
- Activation of complement: A collection of proteins which ultimetly lead to the perforation of pathogen membranes by forming a pore in the membrane allowing water and ions to enter the cell causing the cell to lyse
- Agglutination: Cause pathogens to stick together so they are prevented from entering cells and easier for phagoctyes to ingest
Immunity
Immunity is due to:
- Presence of antibodies that recognize antibodies
- Memory cells that allow for the production of antibodies
Primary Immune Response: Launched the first time pathogen infects the body
Secondary Immune Response: Launched second time pathogen infects the body
Memory cells ensure the second time an antigen is encountered the body is ready to respond rapidly by producing antibodies at a faster rate
Vaccine: Live attenuated (weakened) version of the pathogen
- A vaccine is introduced (usually through injection) into the body
- Stimulates a primary immune response
- If the pathogen enters the body it is destroyed by
antibodies during a secondary immune response which is much faster and stronger so little to no symptoms are experienced
Smallpox
Smallpox was the first infectious disease to have been eradicated by vaccination
Cowpox is a mild viral infection of cows very similar to Smallpox
Edward Jenner's procedure:
- 1796 delibrately infected an 8 year old boy with Cowpox using the blisters of a milkmaid who had this disease
- Attempted to infect the boy with Smallpox but found that he was immune
- This testing was repreated on a small group of people and Jenner himself
- Jenner's testing procedure is considered unethical:
- No prior research had been done before human testing to determine the effectiveness and possible side - effects
- Informed consent was not given
- Initial testing was done on a child which would not be approved
That's all for this post!
References:
- https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.livescience.com%2Fantibodies.html&psig=AOvVaw1v_B2VXe6M6dzKjoHk6eRS&ust=1626202520068000&source=images&cd=vfe&ved=0CAoQjRxqFwoTCIirl9ua3vECFQAAAAAdAAAAABAD
- https://www.google.com/url?sa=i&url=https%3A%2F%2Fgfycat.com%2Fstickers%2Fsearch%2Fand%2Bit%2Bturned%2Bout%2Bwell&psig=AOvVaw2_PBGLLqXYoW9bMexXZ0mL&ust=1626201912736000&source=images&cd=vfe&ved=0CAoQjRxqFwoTCPCAna2Y3vECFQAAAAAdAAAAABAO
Drafted by Venetia (Biology)