Immunoblot analysis of VSA abundance in the clinical isolate #5 and the 3D7 strain.

Abstract

<p><b>A, B</b>: Isolate #5 (h: time of <i>in vitro</i> cultivation) and 3D7 (hpi: hours post infection) at successive developmental stages were harvested (<b>A</b>), and differences in VSA abundance in the membrane fraction were assessed by immunoblot using α-RIF40, α-RIF44, α-RIF50, α-STEVOR-mix, α-<i>Pf</i>MC-2TM-SC, and α-<i>Pf</i>MC-2TM-CT antisera (<b>B</b>). As expected, RIFIN and STEVOR were present at higher levels in the clinical isolate; in contrast, <i>Pf</i>MC-2TM proteins were quantitatively increased in 3D7 parasites. Differences were most obvious in pigmented parasite stages (trophozoites, schizonts, left), which also exhibited the highest levels of protein during intraerythrocyic development, but upon longer exposure (*), similar results were also observed for ring stage parasites (right). The luminal endoplasmic reticulum (ER) protein BiP (HSP70) served as a loading control.</p