Interaction of Aspergillus fumigatus spores and pulmonary alveolar macrophages of rabbits.

The in vitro and in vivo interaction of rabbit pulmonary alveolar macrophages (PAM) and Aspergillus fumigatus spores was studied. In vitro experiments showed that PAM from normal rabbits failed to appreciably kill A. fumigatus spores in 4 hours, while A. flavus and A. niger spores were destroyed effectively. Prior opsonization of the spores with normal rabbit serum, rabbit anti-A. fumigatus serum, complement or lung lavage fluid has no profound enhancing effect on the phagocytosis or killing of the spores. Activated macrophages, however, killed slightly more spores than normal macrophages. When A. fumigatus spores were injected intratracheally into rabbits, no dissemination to organs other than the lungs was detected during the first hour, while dissemination to the liver, spleen and kidneys was observed one hour after the inoculation. Free spores in the bronchoalveolar washings and ingested spores in macrophages diminished in 4 hours, while spores in the lung homogenate increased considerably.