Studies on malaria in Papua New Guinea: comparison of the surface glycoproteins on red blood cells from infected and uninfected individuals

Abstract

SUMMARYThe levels of erythrocyte membrane sialic acid from 17 patients withPlasmodium falciparummalaria and 1 withPlasmodium vivaxmalaria, in Papua New Guinea, have been compared with 9 uninfected controls. The amounts of radioactivity incorporated into the major erythrocyte glycoproteins by the periodate/NaB3H4or galactose oxidase plus neuraminidase/NaB3H4methods were unchanged by malaria infection. The electrophoretic mobilities of these proteins also were unaffected. Several new glycoprotein bands with molecular weights (mol. wt) of 160000, 89000, 46000, 42000 and 33000 Daltons were labelled on the surface of erythrocytes from infected individuals; however, none of these bands appeared inallmalarious samples. Sialic acid levels on the erythrocyte membrane were also measured by exhaustive neuraminidase treatment and quantitative assay of released sialic acid. The amount of sialic acid was raised in 1 infected individual, within the normal range for Europeans in 4 others, and below this range with 3 patients. Apparently, extensive removal or modification of sialic acid on the surface of uninfected erythrocytes does not occur in human malaria, in contrast to the results obtained in earlier studies with the lethal murine malarias.