Figure 2.

Application of FAP-tPDT in monolayer culture of primary lesional SSc skin fibroblasts. In three fibroblast cell strains, a dose range of PS-FAP antibody construct was applied and cell viability was measured using CTG after exposure to light and compared to cells not exposed to light. The PS-FAP antibody construct dose-dependently killed fibroblasts with a LD₅₀ of approximately 0.25 nM but only in cells exposed to light (A). Application of a PS-non-targeting antibody (DP47GS) construct had no effect on fibroblast viability (B). (n = 4 replicates per donor). Cell viability decreases after FAP-tPDT as measured by the MTT assay. Cells were incubated with 0 or 10 nM 28H1-700DX or 0.5 M NaOH. No cell death was observed in the cells not exposed to light or not incubated with the antibody. Results are depicted as mean with SD (n = 4 or n = 3 for cells not incubated with the antibody (0 nM)) (C). *** = p < 0.001.