Pulmonary surfactant protein A stimulates chemotaxis of alveolar macrophage.
Pulmonary surfactant modulates several functions of alveolar macrophages including phagocytosis, killing, and chemotaxis. We hypothesized that the reported stimulatory effect of surfactant on macrophage migration was mediated by one of the surfactant proteins, SP-A. We found that macrophage migration was stimulated by SP-A in a concentration-dependent manner. A concentration of 105 micrograms SP-A/ml enhanced migration approximately 10-fold. Heat treatment or reduction and alkylation of SP-A reduced its stimulatory effect. A checker-board analysis showed that SP-A stimulated migration primarily by enhancing chemotaxis (directed movement) rather than chemokinesis (random movement). The interaction of SP-A with macrophages may be mediated at least partly by the collagen-like domain of SP-A. We speculate that SP-A may play a multifunctional role in regulating pulmonary immune response by stimulating multiple macrophage functions.
Wright
J R
JR
Cardiovascular Research Institute, University of California, San Francisco 94143.
Youmans
D C
DC
D000818:Animals; D002633:Chemotaxis / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D006023:Glycoproteins / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D016676:Macrophages, Alveolar / Q000187:drug effects / Q000502:physiology*; D008297:Male; D010446:Peptide Fragments / Q000494:pharmacology; D011510:Proteolipids / Q000494:pharmacology*; D037662:Pulmonary Surfactant-Associated Protein A; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins / Q000494:pharmacology; D015054:Zymosan / Q000494:pharmacology
D006023:Glycoproteins; D010446:Peptide Fragments; D011510:Proteolipids; D037662:Pulmonary Surfactant-Associated Protein A; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants; D011994:Recombinant Proteins; D015054:Zymosan