Vaccination and Immunity: Immunological Memory, Vaccination, Passive Immunity
Edited by Jamie (ScienceAid Editor), Administrator, Taylor (ScienceAid Editor)
Vaccination and Immunity
After an immune response, memory cells are produced. These lay dormant in the lymphatic system for many years. If they detect a pathogen with the specific antigen, they rapidly clone, and secrete antibodies. This means that secondary exposure to a pathogen produces a much more rapid secondary response, and you are not as badly affected the second time the virus appears. This is an important function in vaccinations. See the image below.
You might think it odd then, that we can suffer from flu several times. The reason is that there are different types: influenza - type A, B and C, and within these types of flu, there are various strains. This variation in pathogens means that it is difficult to develop an immunity to so many different pathogens.
A vaccine takes advantage of the secondary response effect. It contains an antigen from pathogens, and this induces the production of memory cells - giving protection from infection by that particular organism.
There are several types of vaccine used, these are:
|Name and Example||Production|
| Killed virulent organisms.
|The pathogen is killed and the antigens remain so an immune response is induced without the pathogen spreading.|
| Live non-virulent strains.
|A strain of pathogen that doesn't cause disease but still causes antibody production.|
| Modified toxins.
|A modified version of toxin treated with heat or chemicals, shouldn't produce symptoms but still triggers a response.|
| Isolated antigens from a pathogen.
|The antigen is separated from the pathogen and injected separately.|
| Genetically engineered antigens.
|The antigens have been isolated and made by genetic engineering, These are injected without the virus.|
This is when the antibodies themselves are given to prevent infection. This occurs naturally for babies when a type of milk called colostrum is produced by mothers that contains lots of antibodies. Passive immunity can also be artificially induced if someone is given an antibody by injection.
Passive immunity is only temporary and will last a few months at most. This is because they are not your own antibodies and they will be removed by the body.
- If you have problems with any of these steps, ask a question for more help, or post in the comments section below.
Categories : Micro
Recent edits by: Administrator, Jamie (ScienceAid Editor)