Compound 1–Induced Parasite Growth Inhibition and BAG1 Expression

<div><p>(A) Parasites allowed to invade an HFF monolayer, and then treated 1, 2, 3, or 6 h with 3 μM Compound 1, express maximal levels of BAG1 after 3-h treatment (light bars). Similar BAG1 expression was observed with host monolayers that were pretreated with Compound 1 (dark bars).</p><p>(B) Phase image of pH-induced vacuole is shown at 72 h postinfection. Following immunostaining with dolichos lectin, note the phenotypic similarities between cyst wall formation in alkaline media and that induced by 3 μM Compound 1.</p><p>(C) Treatment of extracellular (out) or intracellular parasites (in) with 3 μM Compound 1 for 3 h was unable to induce BAG1 expression following infection of untreated HFF monolayers (72 h postinfection). Compare percent BAG1 induction with VEG parasites that remained in a pre- or post-treated culture for 72 h.</p><p>(D) Type I RH and GT-1 tachyzoites inoculated into Compound 1 (3 μM for 3 h)–pretreated HFF cells displayed little or no BAG1 expression (light bars), while in type III VEG or type II ME49B7 cultures, 68% to 75% of parasites express BAG1. Note that parasite growth is dramatically affected in VEG and ME49B7 cultures but not in RH or GT-1 parasites (black bars). The <i>x</i>-axis in this graph is used to plot both percent BAG1⁺ and average vacuole size.</p>