Innate immunity: an overview.

Though sometimes portrayed as "new," the science of innate immunity made its start more than 100 years ago. Recent progress has reflected the application of new methods to old problems. In particular, genetic dissection of innate immune pathways has been pursued with great success in model organisms. This has opened the way to an understanding of innate immune sensing. The effector arm of innate immunity has also been tackled, largely though the use of biochemical methods.