Plasmodium falciparum; merozoite invasion rate in erythrocytes with b-thalassaemia trait and glucose-6-phosphate dehydrogenase deficient genes

ABSTRACT

The malaria parasite invasion-erythrocyte membrane protein variation hypothesis was tested on red cells collected from subjects with G-6-PD deficiency and -thalassaemia trait genes. A series of in vitro competition assays were carried out by using serial dilution technique and the FITC-labelling method (1). The results showed that the invasion rates of P. falciparum merozoites into two G-6-PD hemizygotes deficient cell were Gd- 100 Percent of normal and Gd-Myanmar 95 Percent of normal. But in erythrocytes from two patients with double gene defects viz. G-6-PD mild deficient gene GdB-with -thalassaemia trait gene was 25 Percent and G-6-PD severely deficient gene Gd-Myanmar with -thalassaemia trait gene was 20 Percent susceptible to merozoite invasion. The invasion rate of malaria merozoites in these cells could be inhibited by the partial loss of vital attachement of the red cell membrane required for the process of invasion.