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Updated: Jun 2, 2026
Separation of Plasmodium falciparum Late Stage-infected Erythrocytes by Magnetic Means
Published on: March 2, 2013
Comparison of the in vitro invasive capabilities of Plasmodium falciparum schizonts isolated by Percoll gradient or
Carmenza Spadafora1, Lucia Gerena, Karen M Kopydlowski
1Cellular Injury Department, Division of Military Casualty Research, Walter Reed Army Institute of Research, 503 Robert Grant Ave,, Silver Spring, MD 20902, USA. cspadafora@indicasat.org.pa
Background:
Percoll gradient centrifugation is often used for synchronization, enrichment, or isolation of a particular stage of Plasmodium falciparum. However, Percoll, a hyperosmotic agent, may have harmful effects on the parasites. Magnetic bead column (MBC) separation has been used as an alternative. This is a report of a head-to-head comparison of the in vitro invasive capabilities of parasites isolated by either of the two methods.
Methods:
The P. falciparum laboratory strain isolate 7G8 was grown in vitro using standard procedures and synchronized using 5% sorbitol. On separate days when the schizont parasitaemia was >1%, the culture was split and half was processed by Percoll gradient centrifugation and the other half by magnetic bead column separation. Both processed parasites were placed back in culture and allowed to invade new uninfected erythrocytes.
Results:
In 10 paired assays, the mean efficiency of invasion of 7G8 parasites treated by Percoll gradient centrifugation was 35.8% that of those treated by magnetic bead column separation (95% CI, p = 0.00067) A paired t test with two tails was used for these comparisons.
Conclusions:
In this comparison, magnetic bead column separation of 7G8 schizonts resulted in higher viability and efficiency of invasion than utilizing Percoll gradient centrifugation.
Insights
Magnetic bead column separation of Plasmodium falciparum (P. falciparum) schizonts demonstrated superior in vitro parasite invasion efficiency compared to Percoll gradient centrifugation. This method preserves parasite viability for better experimental outcomes.
Area of Science:
- Malariology
- Parasitology
- Cell Biology
Background:
- Percoll gradient centrifugation is a common method for Plasmodium falciparum isolation but may harm parasites due to its hyperosmotic nature.
- Magnetic bead column (MBC) separation offers a potential alternative for parasite isolation.
- A direct comparison of parasite invasive capabilities after isolation by these two methods is warranted.
Purpose of the Study:
- To compare the in vitro invasive capabilities of Plasmodium falciparum parasites isolated by Percoll gradient centrifugation versus magnetic bead column separation.
- To evaluate the impact of isolation method on parasite viability and subsequent invasion efficiency.
Main Methods:
- Plasmodium falciparum (strain 7G8) cultures were synchronized using sorbitol.
- Cultures were split, with one half processed by Percoll gradient centrifugation and the other by magnetic bead column separation when schizont parasitaemia exceeded 1%.
- Both isolated parasite populations were used to invade new erythrocytes in vitro.
Main Results:
- Magnetic bead column separation resulted in significantly higher parasite invasion efficiency compared to Percoll gradient centrifugation.
- In paired assays, Percoll-treated parasites showed 35.8% invasion efficiency relative to MBC-treated parasites (p = 0.00067).
- Paired t-tests confirmed the statistical significance of the observed differences.
Conclusions:
- Magnetic bead column separation is a superior method for isolating Plasmodium falciparum 7G8 schizonts.
- MBC separation leads to higher parasite viability and enhanced invasion efficiency compared to Percoll gradient centrifugation.
- This finding has implications for improving experimental designs in malaria research.
