Fig. 5. Functionality of candidate effectors at the mpc cell membrane; apoptosis assays. STS-treated mpcs were co-cultured with or without MPs in the presence or absence of antibodies directed against CX3CL1 and CX3CR1, VCAM-1 and VLA-4, ICAM-1 and LFA-1, or PECAM-1 (see bottom of figure). (A,B) Apoptosis of mpcs was evaluated by annexin V labelling (A) and DIOC-6 staining (B) after exclusion of CD14⁺ cells. (C) Myoblast (white bars) and myotube (black bars) apoptosis was evaluated by caspase-3 activity measurement. Results are expressed as percentage of apoptosis in STS-treated mpcs and are means ± s.e.m. of at least three experiments.