The triple culture consists of two steps of interaction. Step I: hDFSC interaction with bacteria. In a second step, primed hDFSCs were allowed to interact with neutrophils in direct and indirect (two chamber system) contact experiments (Step II). Unprimed hDFSCs, bacteria, fresh medium or conditioned DMEM media from the initial co-culture (Step I), which was carried over in the second step, were used as controls. Stem cells were preincubated with oral bacteria under anaerobic conditions at MOI = 100 (Step I). For the direct contact experiments, freshly isolated neutrophils were incubated with hDFSCs at a ratio of 1:10 under anaerobic conditions (Step II). At each experimental level, several phenotypes were analyzed as denoted in the figure.