Figure 5: Ceramide and S1P levels in TAMs from SCCVII tumors incubated with supernatants from PDT-treated SCCVII cells. Supernatants from cultures of in vitro grown SCCVII cells treated by PDT as described for Figure 1 were collected either after first 2 hours, first 6 hours or 3-24 hours of post-incubation. Cells from untreated SCCVII tumors were incubated with the supernatants for 5 hours before they were collected for antibody staining (performed as described for Figure 3) followed by flow cytometry. The bars denote SD; *=statistically significant difference from the values in control TAMs not co-incubated with SCCVII cells.