Effects of surfactant protein A and NaCl concentration on the uptake of Pseudomonas aeruginosa by THP-1 cells.
In the present study, we characterized a model system in which we examined the effects of human surfactant protein A (SP-A) on the uptake of a common human pulmonary pathogen, Pseudomonas aeruginosa, by a human monocytic/macrophage cell line, THP-1 cells. We found that SP-A significantly increases uptake of the bacteria in a dose-dependent manner. Bacterial uptake was temperature-dependent, because an effect of SP-A on bacterial uptake was observed at 37 degrees C and not at 4 degrees C. The continued presence of SP-A during the period when the bacteria and THP-1 cells were co-incubated was necessary for enhanced uptake. Pre-incubation of the bacteria or THP-1 cells with SP-A, followed by washing, abolished the effect of SP-A on bacterial uptake. The effect of SP-A could be inhibited by high concentrations of mannose, but was not affected by the removal or addition of lipopolysaccharide (LPS). Finally, we observed that the SP-A-mediated increase in uptake of P. aeruginosa by THP-1 cells was optimal in a narrow (100 mM and 150 mM) range of NaCl concentrations. We conclude that SP-A enhances the THP-1 cell-mediated uptake of P. aeruginosa in a manner dependent on temperature, the concentration of SP-A, and the concentration of NaCl.
Khubchandani
K R
KR
Department of Anatomy and Cell Biology, University of Iowa College of Medicine, Iowa City, Iowa 52242, USA.
Oberley
R E
RE
Snyder
J M
JM
D016667:Bacterial Capsules / Q000378:metabolism; D003550:Cystic Fibrosis / Q000150:complications / Q000276:immunology / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D006025:Glycosaminoglycans / Q000378:metabolism; D006801:Humans; D008070:Lipopolysaccharides / Q000494:pharmacology; D008353:Mannitol / Q000494:pharmacology; D008358:Mannose / Q000494:pharmacology; D009000:Monocytes / Q000187:drug effects* / Q000502:physiology; D009994:Osmolar Concentration; D010587:Phagocytosis / Q000187:drug effects* / Q000502:physiology; D018410:Pneumonia, Bacterial / Q000209:etiology / Q000276:immunology / Q000378:metabolism; D011510:Proteolipids / Q000494:pharmacology*; D011552:Pseudomonas Infections / Q000209:etiology / Q000276:immunology / Q000378:metabolism; D011550:Pseudomonas aeruginosa / Q000378:metabolism; D037662:Pulmonary Surfactant-Associated Protein A; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants / Q000494:pharmacology*; D012462:Saline Solution, Hypertonic / Q000494:pharmacology; D012965:Sodium Chloride / Q000494:pharmacology*; D013696:Temperature
D006025:Glycosaminoglycans; D008070:Lipopolysaccharides; D011510:Proteolipids; D037662:Pulmonary Surfactant-Associated Protein A; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants; D012462:Saline Solution, Hypertonic; C046129:mucoid exopolysaccharide (P aeruginosa); D008353:Mannitol; D012965:Sodium Chloride; D008358:Mannose