Figure 3.

GRA5 is exocytosed in a soluble form by extracellular parasites. Extracellular tachyzoites were incubated in a secretory medium for 3 h. Parasites (Tg) were sedimented by centrifugation at 1300 × g (LSP). A fraction of the LSS was further separated into 100,000 × g pellet (HSP) and supernatant (HSS). Equal percentages of the LSP, LSS, HSS, and HSP fractions were analyzed by Western blotting probed with both the anti-SAG1 and the anti-GRA5 mAbs. The fraction of GRA5 released in the supernatant (LSS) was found exclusively associated with the soluble fraction (HSS), whereas, in control, the SAG1 surface protein remained exclusively associated with the parasite fraction (LSP).