SIZE OF THE POOL OF ALVEOLAR NEUTROPHILS IN NORMAL RABBIT LUNGS

Morphometric methods and two unique characteristics of neutrophils enabled us to measure the size of the pool of neutrophils in alveoli of rabbit lungs. Rabbit lungs contained an estimated 6.11 x 104 alveolar neutrophils/g wet wt of lungs, and 9.57 x 105 alveolar neutrophils/rabbit. Lung lavage was successful in removing an average of 42.2% of the neutrophils in the air containing spaces of the lungs. An average of 2.5 ± 3.5 (SD)% of the cells in the lung washes were neutrophils, but an average of 10.23 ± 5.0 (SD)% of the cells that were free in the alveolus were neutrophils. Studies of the interaction of alveolar macrophages and neutrophils in vitro showed that neither cell phagocytoses or destroys the other in significant quantities; however, alveolar macrophages containing neutrophils have been observed.