Polylactosamines are not obligate receptors for invasion of Plasmodium falciparum malaria as shown in HEMPAS variant II-gal- erythrocytes.
A HEMPAS (hereditary erythroblastic multinuclearity with positive acidified serum test) erythrocyte, atypical Variant II (referred to herein as Variant II-gal-), lacking long-chain polylactosamine on both glycoproteins (Band 3 and 4.5) and glycosphingolipids, was characterized by the carbohydrate profile of the erythrocyte membrane according to Fukuda et al. (Blood, 73, 1331-1339, 1989). Two laboratories previously reported that polylactosamine isolated from the erythrocyte protein Band 3 inhibited invasion of red blood cells by Plasmodium falciparum in malarial culture, suggesting a role for this carbohydrate in adhesion of the parasite. Therefore, HEMPAS erythrocyte Variant II-gal- presented a unique opportunity to further examine this premise. Freshly drawn blood samples (normal and HEMPAS Variant II-gal-) were separately incubated with P. falciparum from mannitol-synchronized cultures. The parasite was found to invade HEMPAS Variant II-gal- erythrocytes at a 30% lower rate through two life cycles, as shown by microscopic evaluation of invasion and by [3H]hypoxanthine incorporation into parasite. This observation, along with the published fact that glycophorin-deficient MkMk cells are also infectable, but at a lower rate, indicates that neither sialoglycoproteins nor polylactosamines are an obligate adhesive ligand for P. falciparum, although the possibility remains that either may still contribute to adhesive events during infection.
Dhume
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ST
Department of Biochemistry, Louisiana State University, Baton Rouge 70803, USA.
Adams-Burton
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CR
Shumak
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KH
Laine
R A
RA
D000606:Amino Sugars / Q000097:blood*; D000742:Anemia, Dyserythropoietic, Congenital / Q000097:blood* / Q000235:genetics; D000818:Animals; D001457:Anion Exchange Protein 1, Erythrocyte / Q000737:chemistry / Q000235:genetics; D001798:Blood Proteins / Q000737:chemistry / Q000235:genetics; D002448:Cell Adhesion / Q000502:physiology; D004912:Erythrocytes / Q000378:metabolism* / Q000469:parasitology*; D005690:Galactose / Q000737:chemistry; D014644:Genetic Variation; D006031:Glycosylation; D006801:Humans; D066298:In Vitro Techniques; D008024:Ligands; D016778:Malaria, Falciparum / Q000097:blood* / Q000469:parasitology*; D010963:Plasmodium falciparum / Q000254:growth & development / Q000472:pathogenicity / Q000502:physiology*; D011134:Polysaccharides / Q000097:blood*; D011956:Receptors, Cell Surface / Q000378:metabolism
D000606:Amino Sugars; D001457:Anion Exchange Protein 1, Erythrocyte; D001798:Blood Proteins; D008024:Ligands; D011134:Polysaccharides; D011956:Receptors, Cell Surface; C066929:polylactosamine; D005690:Galactose