Fig. 1.
Exposure of M.tb to elderly human ALF is associated with increased intracellular bacterial growth in ATs. ATs were infected with ALF-exposed M.tb (H37Rv-Lux) for 2 hours at MOI of 10:1 followed by 1 hour of gentamicin to kill extracellular M.tb. (A) No differences in bacteria inoculum between conditions. (B) Infected monolayers in 96-well plates were read for increased luminescence (indicative of M.tb H37Rv-Lux intracellular growth in ATs) at the indicated time points, using the GloMax® reading system. Cumulative data of n = 4 (mean ± SEM) in triplicate, using four different A-ALFs and E-ALFs. (C) M.tb intracellular growth in ATs was assessed by colony-forming units (CFUs). Cumulative data of n = 2 (mean ± SEM) in triplicate, using two different A-ALFs and E-ALFs at the indicated time points. Student’s unpaired t test analysis of Adult versus Elderly at each time point, *p < 0.05, **p < 0.01. The “n” values represent the number of biological replicas using an individual ALF sample from different adult or elderly human donors. A = adult ALF-exposed M.tb (white bar); ALF = alveolar lining fluid; ATs = alveolar epithelial type cells; CFUs = colony-forming units; E = elderly ALF-exposed M.tb (black bar); MOI = multiplicity of infection; M.tb = Mycobacterium tuberculosis; ns: no significant differences; RLUs = relative light units; SEM = standard error of the mean.