Decreased membrane deformability in Melanesian ovalocytes from Papua New Guinea.

Abstract

The ability of Melanesian ovalocytes from Papua New Guinea to be deformed was examined in order to probe the resistance of these cells to invasion by several species of malaria parasite [Plasmodium falciparum and P. knowlesi]. Ovalocytes were refractile to drug-induced endocytosis, that they formed abnormal rouleaux, showed reduced deformability when aspirated into 0.6-.mu.m diameter proes 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-.mu.m 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. Apparently, the resistance of ovalocytes to undergo localized deformation might be significant in explaining the resistance of these cells to invasion by malarial merozoites.