Modification of the Mechanical Properties of Red Blood Cell Membrane by Spent Plasmodium falciparum Culture Supernatant

The effect of spent culture supernatant on RBC membrane mechanical properties, RBC membrane deformability and stability, were assayed by ektacytometry after treating RBC ghost membranes with spent Plasmodium falciparum (P. falciparum) malaria culture supernatant fluid (Pf(+)), malaria culture medium which had not been exposed to P. falciparuminfected RBCs Pf(-), and malaria culture medium from an in vitro culture system containing uninfected RBCs (M). All treated RBC membranes were less deformable, and more stable than control, untreated RBC membranes. However, compared to controls, Pf(+)-treated RBC membranes were more deformable than both Pf(-)-treated and M-treated RBC membranes. Similarly, Pf(+)-treated RBC membranes were more stable than membranes treated with both Pf(-) and M. The deformability and stability of Pf(+)-treated RBC membranes were significantly different from membranes treated with both Pf(-) and M (P ≤ 0.05). However, there was no significant difference between deformability and membrane stability for Pf()-treated and M-treated RBC membranes. Our results suggest that spent P. falciparum culture supernatant may significantly modify RBC membrane mechanical properties.