Effects of surfactant lipids and surfactant protein a on host defense functions of rat alveolar macrophages.
Survanta is commonly used as replacement therapy in newborn infants suffering from surfactant deficiency. We investigated the effects of Survanta and surfactant-like liposomes in the presence and absence of surfactant protein A (SP-A) on host defense functions of rat alveolar macrophages (AM). Phagocytosis of Streptococcus pneumoniae by AM was significantly inhibited in the presence of 100 microg/mL of Survanta. The ability of SP-A to enhance phagocytosis of S. pneumoniae was significantly compromised upon exposure to either Survanta or liposomes, although the overall level of phagocytosis remained higher than in the absence of SP-A. This inhibitory effect was not overcome by opsonization of the bacteria with SP-A before incubation with Survanta and AM. We also found that the ability of SP-A to mediate the association of group B Streptococcus with AM was compromised to a significant degree when exposed to either Survanta or liposomes in concentrations of 150 and 250 microg/mL. However, at most concentrations of Survanta or liposomes tested, the presence of SP-A resulted in significantly higher levels of bacterial association. These data show that Survanta and surfactant-like lipids suppress host defense functions of AM in the presence and absence of SP-A in vitro, although SP-A continues to enhance host defense functions overall.
Golioto
Annmarie
A
Neonatal-Perinatal Research Institute, Duke University Medical Center, Durham, North Carolina 27710, USA.
Wright
Jo Rae
JR
D000818:Animals; D001688:Biological Products; D002469:Cell Separation; D005434:Flow Cytometry; D006801:Humans; D008081:Liposomes; D016676:Macrophages, Alveolar / Q000187:drug effects / Q000276:immunology*; D008297:Male; D010587:Phagocytosis / Q000187:drug effects; D011510:Proteolipids / Q000276:immunology*; D037662:Pulmonary Surfactant-Associated Protein A; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants / Q000737:chemistry / Q000276:immunology* / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013296:Streptococcus pneumoniae / Q000276:immunology*
D001688:Biological Products; D008081:Liposomes; D011510:Proteolipids; D037662:Pulmonary Surfactant-Associated Protein A; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants; C072197:beractant