Fluctuations in the frequencies of lung macrophage and dendritic cell phenotypes during infection. Single-cell suspensions of BAL samples obtained from the right diaphragmatic and cardiac lobes of uninfected (NC) and infected pigs were stained for multicolour flow cytometry to detect fluctuations in the A total CD163+ cell population and the B normalized dead CD163+ cells at each necropsy day. The dynamics of the respiratory macrophage/DC network were observed by flow cytometric analysis of the BAL cells. C MHC-II+ cells were identified and further divided into five subsets based on the expression of CD163 and CD172a. Two subsets fitted to the macrophage lineage and were recognized as D CD172a+/CD163high/MHC-II+ (alveolar macrophages; AM) and E CD172a+/CD163int/MHC-II+ (monocyte-derived macrophages; moMɸ), whereas the remaining three subsets were classified as dendritic cells and were identified as F CD172a+/CD163low/MHC-II+ (monocyte-derived dendritic cells; moDCs), G CD172a−/CD163−/MHC-II+, and H CD172a+/CD163−/MHC-II+. The bars represent the means, and the error bars represent the standard errors of the mean (SEM). Bars showing asterisks and different letters represent values that differ significantly from each other (* indicates p ≤ 0.05, ** indicates p ≤ 0.01 and *** indicates p ≤ 0.001).