Even after 24 #selleck inhibitor randurls[1|1|,|CHEM1|]# h, the viability (Figure 4A) and cell cycle profiles (Figure 4B) were not significantly different for RAW264.7 cells cultured in the absence or presence of FBS. The metabolic activity of RAW264.7 cells

increased after 24 h, but significantly more so in the presence than absence of FBS (Figure 4C), which we speculate was due to greater overall proliferation and number of cells in FBS-enriched medium. These results confirmed that, for at least 4 h, in vitro models of infection can be conducted under entirely non-germinating culture conditions without loss of host cell viability, cell cycle progression, or metabolic function. Figure 4 Effect of non-germinating conditions on RAW264.7 cell viability, cell cycle progression, and metabolic activity. RAW264.7 cells were incubated at 37° in DMEM in the presence (+, black bars) or absence (-, white bars) of FBS, and then evaluated at 4 or 24 h, as indicated, for viability (A), cell cycle progression (B), and metabolic activity (C). (A) The cells were assayed for PI uptake, as described

check details under Materials and Methods. The data are rendered as the relative PI uptake normalized at both 4 and 24 h to cells incubated in the absence of FBS. (B) The cells were analyzed for their cell cycle profiles, as described under Materials and Methods. The data are rendered as the relative numbers of cells in G2/M normalized at both 4 and 24 h to cells incubated in the absence of FBS. (C) The cells were analyzed for conversion of MTT to formazan. The data are rendered as the fold change of formazan production normalized at both 4 and 24

h to cells incubated in the absence of FBS. To generate the bar graphs, data Tangeritin were combined from three independent experiments, each conducted in triplicate. Error bars indicate standard deviations. The P values were calculated to evaluate the statistical significance of the differences in viability (A), cell cycle progression (B), and metabolism (C) between cells cultured in the absence or presence of FBS. Germination state of spores does not alter the uptake by mammalian cells The demonstration that cultured RAW264.7 cells remained viable and functional in FBS-free cell culture medium did not directly address the possibility that spore uptake by mammalian cells might be substantially different under germinating and non-germinating cell culture conditions. To evaluate this issue, Alexa Fluor 488-labeled spores were incubated with RAW264.7, MH-S, or JAWSII cells (MOI 10) in the absence or presence of FBS (10%). After 5 or 60 min, intracellular spores were monitored using flow cytometry to measure cell associated fluorescence that was not sensitive to the membrane-impermeable, Alexa Fluor 488 quenching agent, trypan blue [46].