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Possible basis for membrane changes in nonparasitized erythrocytes of malaria-infected animals
Abstract:
Previous studies (Gupta et al. (1982) Nature 299, 259-261) have shown that nonparasitized erythrocytes of Plasmodium knowlesi-infected monkeys contain the procoagulant phospholipid phosphatidylserine (PS) in the outer-half of their membrane bilayer. A reinvestigation of this problem has now revealed that in acute P. knowlesi infection, at least 30% of the infected animals do not have this abnormality. However, PS externalization was a consistent feature in the uninfected red cells of chronically infected animals. Also, a similar membrane change was observed in the red cells of uninfected splenectomized monkeys. These results strongly suggest that spleen plays an important role in maintaining the exclusive inner distribution of PS in the normal erythrocyte membrane, and that partial migration of this lipid to the outer monolayer in nonparasitized erythrocytes could be attributed to an abnormal physiology of this organ in malarial infection.
Insights
Phosphatidylserine (PS) externalization in Plasmodium knowlesi-infected monkey red blood cells is not always present in acute infections. The spleen
Area of Science:
- Malaria research
- Erythrocyte membrane biology
- Parasitology
Background:
- Previous studies indicated phosphatidylserine (PS) externalization in nonparasitized erythrocytes of Plasmodium knowlesi-infected monkeys.
- This phospholipid is typically found on the inner membrane leaflet of healthy red blood cells.
Purpose of the Study:
- To reinvestigate PS externalization in Plasmodium knowlesi infection.
- To determine the role of the spleen in maintaining normal erythrocyte membrane phospholipid distribution.
Main Methods:
- Analysis of erythrocyte membrane phospholipid distribution in infected and uninfected monkeys.
- Comparison of membrane changes in acutely and chronically infected animals.
- Assessment of membrane changes in splenectomized monkeys.
Main Results:
- In acute Plasmodium knowlesi infection, at least 30% of infected animals did not exhibit PS externalization.
- PS externalization was consistently observed in uninfected red cells of chronically infected animals.
- A similar membrane change occurred in the red cells of uninfected splenectomized monkeys.
Conclusions:
- The spleen plays a crucial role in maintaining the inner distribution of PS in normal erythrocyte membranes.
- Abnormal spleen physiology during malaria infection may contribute to PS externalization in nonparasitized erythrocytes.