It is thought that exposure to bacteria, viruses and parasites is important for the healthy development of the immune system. (health-and-parenting.com)
They help with proper development of the immune system, skin, eyes, nervous system, brain and other organs. (newkidscenter.com)
«This progressive colonization is thought to be important for development of immune system tolerance... lack of such tolerance possibly leads to food allergies and chronic inflammation,» the researchers write in Proceedings of the National Academy of Sciences. (genomenewsnetwork.org)