Lungs with a built-in immune system could change how we study respiratory disease

Testing a new vaccine or treatment usually starts with mice — imperfect stand-ins for human lungs. Stanford researchers, funded by the NIH, have built something better: miniature human lungs grown from tissue donated by more than 220 volunteers, with the organ's own immune system intact. In the lab, these organoids mounted real virus-specific immune responses, and a booster dose measurably weakened later infections — suggesting the lungs' local defenses may protect on their own, and opening the door to 'local' vaccines trained at the body's front lines. The platform could replace animal models for some tests and reveal things animal tests never could.