Infectivity of Legionella pneumophila mip mutant for alveolar epithelial cells

Nicholas P. Cianciotto*, Julie Kim Stamos, David W. Kamp

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

56 Scopus citations


Legionella pneumophila can invade and grow within explanted alveolar epithelial cells. Given its potential clinical significance, an examination of the molecular basis of epithelial cell infection was initiated. The mip gene encodes a 24-kilodalton surface protein that promotes macrophage infection and virulence. To determine whether this gene is required for pneumocyte infection, we tested a strain bearing a mip null mutation for its ability to infect both explanted type II cells and type I-like cell lines. For infection of type II cells, the infective dose 50% for the Mip- strain was 25-fold higher than an isogenic Mip+ strain. Type I cell monolayers infected with the mutant for 3 days yielded ∼ 50-fold fewer bacteria than did monolayers infected with the parental strain. These data indicate that Mip enhances infection of pneumocytes and that L. pneumophila employs some of the same genes (mechanisms) to infect epithelial cells and marcophages.

Original languageEnglish (US)
Pages (from-to)247-250
Number of pages4
JournalCurrent Microbiology
Issue number4
StatePublished - Apr 1995

ASJC Scopus subject areas

  • Microbiology
  • Applied Microbiology and Biotechnology


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