Two Genetically Distinct Plasmodium knowlesi Duffy Binding Protein Alpha Region II (PkDBP alpha II) Haplotypes Demonstrate Higher Binding Level to Fy(a plus b plus ) Erythrocytes than Fy(a plus b-) Erythrocytes

摘要

Invasion of human erythrocytes by merozoites of Plasmodium knowlesi involves interaction between the P. knowlesi Duffy binding protein alpha region II (PkDBP alpha II) and Duffy antigen receptor for chemokines (DARCs) on the erythrocytes. Information is scarce on the binding level of PkDBP alpha II to different Duffy antigens, Fy(a) and Fy(b). This study aims to measure the binding level of two genetically distinct PkDBP alpha II haplotypes to Fy(a+b-) and Fy(a+b+) human erythrocytes using erythrocyte-binding assay. The binding level of PkDBP alpha II of Peninsular Malaysian and Malaysian Borneon haplotypes to erythrocytes was determined by counting the number of rosettes formed in the assay. Overall, the Peninsular Malaysian haplotype displayed higher binding activity than the Malaysian Borneon haplotype. Both haplotypes exhibit the same preference to Fy(a+b+) compared with Fy(a+b-), hence justifying the vital role of Fy(b) in the binding to PkDBP alpha II. Further studies are needed to investigate the P. knowlesi susceptibility on individuals with different Duffy blood groups.