Vaccines and Antibodies in Medicine
Vaccines can protect Individuals and Populations against Disease
1. While B-cells are busy dividing to build up numbers to deal with pathogen, you suffer from disease. Vaccination can help avoid this.
2. Vaccines contain antigens – cause body to produce memory cells against particular pathogen without pathogen causing disease. Means become immune without getting any symptoms
3. Vaccines protect individuals that have them – reduce the occurrence of the disease, those not vaccinated are also less likely to catch disease (fewer people to catch it from) called herd immunity.
4. Vaccines contain antigens – free or attached to dead or attenuated (weakened) pathogen.
5. Vaccines may be injected or taken orally. Disadvantages: taking a vaccine orally could be broken down by enzymes in the gut or the molecules of vaccine may be too large to be absorbed into the blood.
6. Booster vaccines – given later on (several years) to make sure that memory cells are produced.
Antigenic Variation helps some Pathogen evade the Immune System
1. Antigens on the surface of pathogens – activate primary response
2. When infected a second time with same pathogen (same antigens on its surface) they activate the secondary response so you don’t get ill.
3. Sneaky pathogens can change their surface antigens. This is called antigenic variation. (Different antigens are formed due to changes in the genes of pathogen)
4. Infected for a second time – memory cells produced from the first infection will not recognise different antigens. Immune system has to start from scratch and carry out a primary response against…