The Duffy binding protein (PkDBPαII) of Plasmodium knowlesi from Peninsular Malaysia and Malaysian Borneo show different binding activity level to human erythrocytes

Table 1 Erythrocyte-binding assays of PkDBPαII of Peninsular Malaysia and Malaysian Borneo using various erythrocytes

Erythrocytes	Treatment	Haplotype	Binding^a	Number of rosettes^b
Human Fy(a+b−)	None	Peninsular	+	156.89 (±6.62)
Human Fy(a+b−)	None	Borneo	+	46.00 (±3.57)
Macaque	None	Peninsular	+	356.56 (±6.75)
Macaque	None	Borneo	+	355.22 (±11.67)
Human Fy(a+b−)	Anti-Fy6	Peninsular	−	−
Human Fy(a+b−)	Anti-Fy6	Borneo	−	−
Macaque	Anti-Fy6	Peninsular	+	352.67 (±2.89)
Macaque	Anti-Fy6	Borneo	+	351.83 (±4.36)

^a Binding of erythrocytes to COS-7 cells expressing PkDBPαII of Peninsular Malaysia and Malaysian Borneo; (+) Binding; (−) no binding
^b Number of COS7 cells with rosettes (mean ± SD) seen in 35–40 fields at 200× magnification by fluorescence microscopy. (+) A positive rosette was defined as more than half the surface of the transfected cells covered with attached erythrocytes, (−) No rosettes seen in the entire well

ISSN: 1475-2875