Rheopathologic Consequence of Plasmodium vivax Rosette Formation
Fig 1
(A) The effect of P. vivax invasion, development and rosetting on the deformability of the infected reticulocyte membrane (normocytes are shown as a comparator). Plot showing membrane shear moduli (SM) (a higher SM indicates a reduced membrane deformability) of different cell types and stages of P. vivax erythrocytic development, with geometric mean (overall of 10 isolates) SM of each group indicated by a red line (each dot represents an individual cell measurement the total ‘n = x’). Pictures of respective cell types before (i) and during (ii) membrane shear modulus measurement by micropipette aspiration are shown under the graph. Mean (Geometric) shear moduli was compared using ANOVA (Bonferroni correction) and multiple comparison test (tukey). Uninfected normocytes were significantly more deformable than uninfected reticulocytes (P< 0.001). However both ring and trophozoite P. vivax stages become progressively more deformable (P< 0.05) until schizont stage (the very mature schizonts ‘segmenters’ were especially rigid). When normocytes adhered (rosette) with schizonts the infected cell membrane became significantly more rigid than non-rosetting schizonts (P< 0.001). (B) The number of normocytes involved in the rosette had no significant effect on the mean deformability kinetics (aspirated length versus the suction pressure) of the IRBCs. Pictures of cells before (i) and during (ii) measurement are shown under the graph. Measurements were done with increasing aspirating pressure until cells became structurally unstable under that pressure point (buckling effect), as shown by pictures (inset).