All human beings get affected by acute and chronic diseases. When we have immunity, our body is able to fight against diseases and infection on its own. But in simple words, being immune means that the body has already fought against the diseases without any symptoms. Sometimes, the immune system is unable to protect us from germs entering the body, which indicates that our system is weak and special care should be taken. The immune system must remain alert and resist invasion from harmful organisms. The immune system is made up of different types of cells and proteins and each play their specific role in fighting against the foreign invaders. Any type of stress, poor diet, alcohol consumption or lack of sleep may weaken the immune system.