The immune system is best known for its role in defending the body from infections but it also serves to maintain balance within the body. At the McMaster Immunology Research Centre scientists study immune regulation at the mucosal tissues which stand between internal organs (e.g. lungs, digestive tract, mammary ducts) and the environment. These tissues are not only the primary defense from infections, but the mucosal tissues also regulate other diseases, such as chronic obstructive pulmonary disease, cancer and allergies. Research from the centre has spawned a novel vaccine for tuberculosis, innovative methods for cancer treatment, new perspectives on the mechanisms and treatment of food allergy, and creative strategies to prevent and manage lung disease.