PT  - JOURNAL ARTICLE
AU  - Nash, T W
AU  - Libby, D M
AU  - Horwitz, M A
TI  - IFN-gamma-activated human alveolar macrophages inhibit the intracellular multiplication of Legionella pneumophila.
DP  - 1988 Jun 01
TA  - The Journal of Immunology
PG  - 3978--3981
VI  - 140
IP  - 11
4099  - http://www.jimmunol.org/content/140/11/3978.short
4100  - http://www.jimmunol.org/content/140/11/3978.full
SO  - J. Immunol.1988 Jun 01; 140
AB  - Human alveolar macrophages activated by human rIFN-gamma inhibit the intracellular multiplication of Legionella pneumophila, an intracellular bacterial pathogen and the agent of Legionnaires' disease. Activation of alveolar macrophages with IFN-gamma is dose dependent; significant inhibition of L. pneumophila multiplication (mean 1.60 +/- 0.20 logs) is achieved consistently with concentrations of IFN-gamma of greater than or equal to 2 x 10(-2) micrograms/ml (220 U/ml). Activation of alveolar macrophages is also time dependent. In macrophages treated continuously after explantation, macrophages infected at 48 to 96 h after explantation are more inhibitory than macrophages infected at 24 h after explantation. In macrophages not treated continuously after explantation but treated for various lengths of time before infection, the longer their exposure to IFN-gamma before infection, the greater the inhibition of L. pneumophila multiplication (96 greater than 72 greater than 48 greater than 24 h). IFN-gamma-activated alveolar macrophages exhibit morphologic signs of activation, including increased size, spreading, and aggregation. This paper demonstrates that a human resident macrophage can be activated with IFN-gamma such that it exhibits enhanced antimicrobial activity against a relevant pathogen.