Our immune system is a complex network of cells, tissues and organs that protects our body from pathogens and other harmful invaders. It acts as a kind of defence system designed to recognize, fight and eliminate pathogens. The main task of the immune system is to produce antibodies that specifically target certain pathogens. These antibodies bind to the pathogens and mark them for destruction by immune cells such as T cells and macrophages. When our body first comes into contact with a particular pathogen, it can take some time for the immune system to produce antibodies that can effectively fight the pathogen. This is the reason why we often experience symptoms such as fever and aching limbs during an infection. However, once the immune system has overcome an infection, it forms an “immune memory”. This means that the immune system is able to remember the specific pathogens and react more quickly and effectively when another infection occurs. This is the reason why we do not normally contract the same disease twice. However, it is important to keep the immune system healthy and strong by eating a balanced diet, getting enough exercise and getting enough sleep. When the immune system is weakened, we are more susceptible to infections and diseases. Therefore, it is important to pay attention to our bodies and watch out for warning signs that our immune system is weakened.