Answer
The receptor for lipopolysaccharide, a key component of the cell wall of Gram-negative bacteria, was discovered by Bruce Beutler. This receptor, called Toll-like receptor 4, plays a critical role in the immune system's response to infection. Beutler's discovery of Toll-like receptor 4 led to a better understanding of how the immune system works and has led to the development of new drugs to treat infections.