Macrophage turnover kinetics in the lungs of mice infected with Streptococcus pneumoniae

Introduction: Streptococcus pneumoniae is the most prevalent cause of community-acquired pneumonia and is known to induce apoptosis and necrosis in macrophages in vivo. We analyzed the kinetics of alveolar and lung parenchymal macrophage replacement by newly recruited exudate macrophages in vehicle treated and S. pneumoniae challenged bone marrow chimeric CD45.1 mice. Methods: Following lethal irradiation, CD45.1 alloantigen-expressing recipient mice were transplanted with bone marrow cells from CD45.2 alloantigen-expressing donor mice. Results: After only 24h of low-dose S. pneumoniae infection, approximately 6…