Diana Tovar

P. falciparum: merozoite surface protein-8 peptides bind specifically to human erythrocytes

This work determined Plasmodium falciparum merozoite surface protein-8 (MSP-8) regions specifically binding to membrane surface receptors on human erythrocytes. Five high activity binding peptides (HABPs), whose binding to erythrocytes became saturable and sensitive on being treated with neuraminidase and chymotrypsin were identified from the MSP-8 protein. Those amino acids directly involved in interaction with erythrocytes were also determined for each one of the HABPs. Some of them specifically recognized 28, 46, and 73 kDa erythrocyte membrane proteins. Some HABPs inhibited in vitro P. falciparum merozoite invasion of erythrocytes by up to 98%, suggesting the MSP-8 proteins possible role in the invasion process.

Erratum to “Peptides of the liver stage antigen-1 (LSA-1) of Plasmodium falciparum bind to human hepatocytes”: [Peptides 24 (2003) 647–657]

Table 2LSA-1 protein high binding peptides and sera analogues invasion and development inhibition assays% Invasion inhibition % Development inhibition100 M 200 M 100 M 200 MPeptide20630 10 ± 434± 20± 30± 320633 48 ± 188± 115± 485± 16762 13 ± 2 100 ± 20± 557± 2Chloroquine 100 ± 2 100 ± 2 100 ± 2 100 ± 2Sera1:1011 70 ± 512 8.8 ± 7Preimmune 9.5 ± 5Chloroquine 100 ± 4Peptides belonging to LSA-1 (20630 and 20633) inhibited in vitro merozoite invasion of erythrocytes. Peptide 20633 has the highest degree of inhibitionparasite invasion and development. Peptide 6762 was used as positive control. As shown, of the two sera assayed, one monkey 11 sera, inhibited invasionby70%, whilst the other two behaved as did the control.