title: CD11b regulates recruitment of alveolar macrophages but not pulmonary dendritic cells after pneumococcal challenge.
abstract: Despite their close physical and functional relationships, alveolar macrophages (AMs) and pulmonary dendritic cells (pulDCs) have rarely been examined together in the context of infection. Using a nonlethal, resolving model of pneumonia caused by intranasal injection of Streptococcus pneumoniae, we demonstrate that AMs and pulDCs exhibit distinct characteristics during pulmonary inflammation. Recruitment of AMs and pulDCs occurred with different kinetics, and increased numbers of AMs resulted mainly from the appearance of a distinct subset of CD11b(High) AMs. Increased numbers of CD11b(High) and CD11b(Low) AMs, but not pulDCs, were recoverable from bronchoalveolar lavage fluid. CD11b expression on AMs was significantly increased by granulocyte-macrophage colony-stimulating factor but not by interleukin-10 or pathogen-associated stimuli. Finally, antibody blockade demonstrated that CD11b was critical for the recruitment of AMs, but not pulDCs, into the lung after pneumococcal challenge. These data demonstrate that there are significant differences between AM and pulDC responses to inflammatory pathogenic stimuli in vivo.
authors.affiliation: Immunology Unit, Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom. ak510@york.ac.uk
authors.forename: Alun C
authors.initials: AC
authors.lastname: Kirby
authors.forename: John G
authors.initials: JG
authors.lastname: Raynes
authors.forename: Paul M
authors.initials: PM
authors.lastname: Kaye
mesh_terms: D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D039481:CD11b Antigen / Q000096:biosynthesis / Q000502:physiology*; D003713:Dendritic Cells / Q000276:immunology*; D004195:Disease Models, Animal; D005434:Flow Cytometry; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000276:immunology; D016753:Interleukin-10 / Q000276:immunology; D008168:Lung / Q000276:immunology*; D016676:Macrophages, Alveolar / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D011018:Pneumonia, Pneumococcal / Q000276:immunology*; D013296:Streptococcus pneumoniae / Q000276:immunology
chemical_list: D039481:CD11b Antigen; D016753:Interleukin-10; D016178:Granulocyte-Macrophage Colony-Stimulating Factor