Ch. Mody et al., LEGIONELLA-PNEUMOPHILA REPLICATES WITHIN RAT ALVEOLAR EPITHELIAL-CELLS, The Journal of infectious diseases, 167(5), 1993, pp. 1138-1145
Legionella pneumophila replicates in the distal pulmonary airspace, ca
using legionnaires' pneumonia. Legionella organisms replicate within a
lveolar macrophages and recruited blood monocytes; however, when these
cells are activated, they become potent inhibitors of L. pneumophila
proliferation. L. pneumophila may replicate in other cells and thereby
avoid the host defenses of macrophages. Experiments demonstrated that
L. pneumophila replicate within primary cultures of rat pulmonary alv
eolar epithelial cells. Double-label immunofluorescent and electron mi
croscopy demonstrated L. pneumophila within epithelial cells. Replicat
ion of L. pneumophila required similar numbers of alveolar epithelial
cells or alveolar macrophages, required viable epithelial cells, and t
ook place intracellularly. While replication of L. pneumophila occurre
d in both serum-free and serum-containing media, it was enhanced in th
e presence of serum. Pulmonary alveolar epithelial cells may represent
an alternative site for replication of Legionella species in the term
inal airspace and thus clarify some previously unexplained aspects of
the pathogenesis of legionnaires' disease.