FIG 2.

Expression of PD-L1: P. gingivalis extracts were fractionated into cytosolic and PDG-containing total membrane (TM) fractions. (A) P. gingivalis was extracted to generate cytosolic (Cyt) and TM fractions. These fractions were separated together with a PDG control by SDS-PAGE and the gel was stained with Coomassie blue. The positions of molecular weight markers are shown; the position of PDG is indicated by a box. (B) The TM fraction and PDG in the indicated concentrations were used to treat SCC-25 cells for 1 day, followed by analysis of PD-L1 expression using Western blot (upper) and a quantitative analysis of three Western blots (lower). (C) Upper: primary human gingival keratinocytes (PHGKs) were incubated with P. gingivalis PDG at the indicated concentrations for 1 day. Cells were harvested and equal amounts of protein contained in cell lysates were used for Western blotting using PD-L1 antibodies. Lower: the results from three Western blots were quantified by Image J. PD-L1 protein expression from unstimulated cells was arbitrarily set as 1; the error bars show standard deviations; *, P < 0.05.