Abstract: The inventors demonstrate that treatment of young, suckling mice with a glycolipid derived from Helicobacter pylori activates NKT cells in a CD1d-restricted fashion, and is protective against AHR in a model of allergen-induced asthma. The inventors further found that this protective effect can be transferred by NKT cells exposed to the glycolipid, and is associated with the expansion of a suppressive double-negative NKT cells and Foxp3+ TReg cells. The inventors also demonstrate herein that pre-treatment of adult mice with a glycolipid derived from Helicobacter pylori partially suppresses airway hyperreactivity and inhibits BAL inflammation in an ozone-exposure model. Accordingly, provided herein are compositions and methods for the treatment and prevention of inflammatory diseases, such as asthma or autoimmune diseases, in a subject in need thereof.