Fig. 8. TM9SF2 and TM9SF4 are required for phagocytosis in S2 cells. S2 cells were untreated (Control) or treated for 3 days with siRNA GFP (Green fluorescent protein), TM9SF4, TM9SF2, PGRP-LC or Dscar, either alone or in combination (TM9SF2+4), as indicated. Cells were then incubated for 10 minutes with FITC-labelled E. coli (A) or FITC-labelled S. aureus (B) and the internalised fluorescence was measured in the presence of external Trypan Blue quenching solution. The phagocytosis index was quantified as the percentage of fluorescence-positive cells multiplied by the mean fluorescence of these cells. We counted 10,000-20,000 cells from each sample. A phagocytosis index of 100% was attributed to control cells. The results presented are the mean ± s.d. of three experiments. Significant differences were observed using Student's t-test between: (A) TM9SF4 and control (P<0.003), TM9SF2 and control (P<0.02), PGRP-LC and control (P<0.001), Dscar and control (P<0.001); and (B) TM9SF2 and control (P<0.001), TM9SF2+4 and TM9SF2 (P<0.05), Dscar and control (P<0.001).