Ptx-like activity of plasma from Ptx-treated mice after incubation with Jurkat cells as targets. After overnight incubation with plasma from Ptx-treated animals [(+) Ptx P], Jurkat cells displayed a Ptx-like defect in SDF-1–induced actin polymerization. Normal plasma [(+) NP] was similar to untreated Jurkat cells [(-) P]. A similar effect was observed when Jurkat cells were incubated with washed RBCs from normal or Ptx-treated mice suggesting a sustained release of Ptx from cellular depots as an explanation for its lingering effect (data not shown). Apart from RBCs, other hematopoietic or nonhematopoietic cells (ie, endothelial cells) could theoretically contribute to this effect, but these were not directly tested.