Concentration and purification by magnetic separation of the erythrocytic stages of all human Plasmodium species

Abstract

Background: Parasite concentration methods facilitate molecular, biochemical and immunological research on the erythrocytic stages of Plasmodium. In this paper, an adaptation of magnetic MACS(R) columns for the purification of human Plasmodium species is presented. This method was useful for the concentration/purification of either schizonts or gametocytes.

Results and conclusions: The magnetic removal of non-parasitized red blood cells (in vivo and in vitro) using magnetic columns (MACS) was evaluated. This easy-to-use technique enriched schizonts and gametocytes from Plasmodium falciparum in vitro cultures with a very high degree of purity. In addition, all haemozoin-containing stages (schizonts and/or gametocytes) from the peripheral blood of infected patients could be concentrated using this method. This method is particularly useful for the concentration of non-falciparum species, which do not grow in culture and are otherwise difficult to obtain in large amounts.

Figure 1

Plasmodium purification with MACS^® (magnification ×100, except C and D: × 40) P. falciparum in vitro culture before (A) and after (B) purification (thin smears). Plasmodium falciparum gametocyte containing blood before (C) and after (D) purification (calibrated thick film). Plasmodium falciparum gametocytes obtained from in vitro culture (E). Plasmodium ovale gametocytes from an infected patient (F). Plasmodium malariae schizonts before (G) and after (H) purification (thin smears)