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. 2019 Mar 29;220(3):514–523. doi: 10.1093/infdis/jiz138

Figure 3.

Figure 3.

Exposure of Mycobacterium tuberculosis (Mtb) to elderly alveolar lining fluid (E-ALF) is associated with increased bacterial intracellular growth in macrophages in vitro. Human monocyte-derived macrophage (hMDM, A) monolayers (shown is a representative experiment in triplicate of n = 8, mean ± standard deviation [SD], using 4 different adult alveolar lining fluids [A-ALFs] and 4 different E-ALFs) and human alveolar macrophages (hAMs, B; shown is a representative experiment in triplicate of n = 3 [mean ± SD], using 3 different A-ALFs and 3 different E-ALFs) were infected with human A-ALF– or E-ALF–exposed Mtb at a multiplicity of infection 1:1. Monolayers were lysed at the indicated time points to assess bacterial burden by colony-forming unit (CFU) counts. Despite similar numbers of bacteria at 2 hours postinfection, E-ALF–exposed Mtb had a significant growth advantage in macrophages at later time points. C, Percentage of E-ALF–exposed Mtb at 2 hours and 96 hours postinfection compared with A-ALF–exposed Mtb. A difference of 57.5% was observed at the 96-hour time point (overall data from n = 3 in triplicate, mean ± standard error of the mean). Student t test of human A-ALF vs E-ALF at each time point. *P < .05, **P < .005, ***P < .0005.