Biology – Blood and the Immune System
The immune system is our body’s natural defense against pathogens – bacteria, protists, fungi and viruses which cause disease. There are two parts to it – the innate and the adaptive immune systems. The innate immune system is a general defense against all pathogens, whereas the adaptive immune system involves a process where different types of white blood cells recognise and kill specific pathogens. Only once we understand how the immune system works, can we begin to understand what the different blood groups are and how people can become immune to certain pathogens.