How does immune system work against  microbes?

Besides tissue-specific or organ-specific effects of an infectious disease, there will be other common effects too. Most of these common effects depend upon the fact that the patient's immune system becomes activated in response to an infection. Activated body's immune system starts recruiting many cells to the affected tissue to kill the disease-causing microbes. This recruitment process of the active immune system is called inflammation. The inflammation results in some local effects such as swelling and pain and general effects such as fever.