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Decreased membrane deformability in Melanesian ovalocytes from Papua New Guinea
Abstract:
We examined the ability of Melanesian ovalocytes from Papua New Guinea to be deformed in order to probe the resistance of these cells to invasion by several species of malaria parasite. We found ovalocytes were refractile to drug-induced endocytosis, that they formed abnormal rouleaux, showed reduced deformability when aspirated into 0.6-micron diameter pores in polycarbonate sieves, and failed to crenate when mounted under a glass coverslip. No substantial differences were found between normocytes and ovalocytes in their initial rate of filtration through 4.5-micron pore polycarbonate sieves, their membrane fluidity as measured by the rate of depolarization of fluorescent probes or the rate of extraction of cytoskeletal proteins in low ionic strength buffers. We conclude that the resistance of ovalocytes to undergo localized deformation might be significant in explaining the resistance of these cells to invasion by malarial merozoites.
Insights
Melanesian ovalocytes from Papua New Guinea resist malaria parasite invasion. Their reduced deformability, unlike normal red blood cells, may explain this resistance.
Area of Science:
- Cell Biology
- Parasitology
- Hematology
Background:
- Melanesian ovalocytes are a distinct red blood cell morphology found in Papua New Guinea.
- Red blood cell deformability is crucial for navigating the microvasculature and parasite invasion.
Purpose of the Study:
- To investigate the deformability of Melanesian ovalocytes.
- To determine if ovalocyte deformability influences resistance to malaria parasite invasion.
Main Methods:
- Assessing ovalocyte deformability using micropore filtration and aspiration into pores.
- Evaluating resistance to drug-induced endocytosis and cell shape changes (rouleaux, crenation).
- Measuring membrane fluidity and cytoskeletal protein extraction.
Main Results:
- Ovalocytes exhibited reduced deformability, failed to crenate, and formed abnormal rouleaux.
- Ovalocytes were resistant to drug-induced endocytosis.
- No significant differences in filtration rates, membrane fluidity, or protein extraction were observed compared to normocytes.
Conclusions:
- Reduced localized deformability of ovalocytes is a key factor contributing to their resistance to malaria merozoite invasion.
- This finding provides insight into host-parasite interactions and potential malaria resistance mechanisms.