When bacteria land in the lungs, innate immune responses determine the outcome. Neutrophils and plasma proteins are essential to eliminating bacteria, but they compromise respiratory physiology. Insufficient responses lead to overwhelming infection and excessive responses cause acute lung injury, so the regulation of these responses is critical. This regulation is the focus of our Pulmonary Center research on pneumonia biology.
The figure alongside this text, from a New England Journal of Medicine review, shows neutrophils in the alveoli of infected lungs, contributing to host defense, immunoregulation, and lung injury.