Plasmodium falciparum lacks sialidase and trans-sialidase activity.
Sialic acid on the red cell surface plays a major role in invasion by the malaria parasite Plasmodium falciparum. The NeuAc(alpha 2,3) Gal motif on the O-linked tetrasaccharides of the red cell glycophorins is a recognition site for the parasite erythrocyte-binding antigen (EBA-175). Consequently, the interaction of P. falciparum and the red cell might share homology with that of the influenza virus. The cellular interactions of P. falciparum were examined for their sensitivity to 4-guanidino-2,3-didehydro-D-N-acetyl neuraminic acid (4-guanidino Neu5Ac2en), a potent inhibitor of influenza virus sialidase. Parasite invasion and subsequent development was unaffected by the sialidase inhibitor. The inhibitor did not affect rosette formation of parasite-infected erythrocytes with uninfected cells nor their cytoadherence to C32 melanoma cells. Furthermore, we were unable to confirm the presence of a previously reported parasite sialidase using sensitive fluorometric or haemagglutination assays, neither was any malarial trans-sialidase identified. We conclude that P. falciparum possesses neither sialidase nor trans-sialidase activity and that an inhibitor of influenza virus sialidase has no effect on important cellular interactions of this parasite.
Clough
B
B
Department of Infection and Tropical Medicine, Imperial College School of Medicine, Northwick Park Hospital, Middlesex, UK.
Atilola
F A
FA
Healy
N
N
Pereira
M E
ME
Bethell
R C
RC
Penn
C R
CR
Pasvol
G
G
D000818:Animals; D002448:Cell Adhesion; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004912:Erythrocytes / Q000469:parasitology; D006146:Guanidines; D006801:Humans; D009439:Neuraminidase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009975:Orthomyxoviridae / Q000201:enzymology; D010963:Plasmodium falciparum / Q000201:enzymology* / Q000254:growth & development / Q000472:pathogenicity*; D011714:Pyrans; D012397:Rosette Formation; D012794:Sialic Acids / Q000494:pharmacology; D053243:Zanamivir
D004791:Enzyme Inhibitors; D006146:Guanidines; D011714:Pyrans; D012794:Sialic Acids; D009439:Neuraminidase; D053243:Zanamivir