What are the features of the innate immune system and how does it perform its function?

During the first critical hours and days of exposure to a new pathogen, we rely on our innate immune system to protect us from infection. Innate immunity depends on a group of proteins and phagocytic cells that recognise consistent features of pathogens and become quickly activated to help destroy them. The innate immune system produces a standardised response against any foreign material entering the body. There are many aspects of this response, some of which are directed at destroying the foreign material and others at stimulating activity in the acquired immune system. Phagocytes are important cells in the innate immune system that can scavenge and ingest microbes to destroy them. The exocytes, which include the eosinophils, mast cells and basophils, produce chemicals that can destroy microbes. Chemicals known as cytokines, which enable communication between different cells, also play an important role in innate immunity. The cells also produce chemicals that stimulate the inflammatory response. Part of the inflammatory response involves dilation of blood vessels which increases blood flow to the inflamed area and allows chemicals produced by the immune system is to enter the tissues together with cells of the innate immune system such as neutrophils.

The innate immune system: the first line of defense

The innate immune system is the first part of the body to detect invaders such as viruses, bacteria, parasites and toxins, or to sense wounds or trauma. Upon detection of these agents or events, the innate immune system activates cells to attack and destroy the outsider, or to initiate repair, while also informing and modulating the adaptive immune response that follows this first line of defense.