Malaria Antigen Profiling for Diagnostics

Selection of peptides specific for P. falciparum representing different life stages of the parasite was based on the work of Ambrosino et al. [5 (link)]. Additionally, peptides specific for Anopheles gambiae saliva protein [5 (link)], P. vivax and Plasmodium malariae were included in the assay, as well as specific recombinant proteins for P. falciparum and P. vivax (Table 1). All peptides were chemically synthesized with an added N-terminal cysteine residue and bovine serum albumin (BSA) (Table 1) [5 (link)] by GeneCust Europe (Dudelange, Luxembourg). The recombinant proteins were synthesized as described in Table 1. This study consisted of two phases (performance assessment of the assay, and application to field samples; Fig. 1). For practical reasons, some steps carried out during the performance assessment used a slightly different Ag set (Fig. 1).Table 1

Overview of the antigens (peptides and recombinant proteins) used in this study

Antigens	Sequence (N-terminal to C-terminal)	g/mol	Life-cycle stages	Plasmodium species	Peptide or recombinant protein	References
CSP	NANPNANPNANPNANPNVDPNVDPC	2557.67	Sporozoite	P. falciparum	Peptide	[5 (link)]
Pfl3	C-terminal His-tag produced in E. coli		Sporozoite	P. falciparum	Recombinant protein	[45 (link), 46 (link)]
STARP-R	STDNNNTKTISTDNNNTKTIC	2299.42	Sporozoite and liver stage	P. falciparum	Peptide	[5 (link), 47 (link)]
SALSA 1	SAEKKDEKEASEQGEESHKKENSQESAC	3123.24	Sporozoite and liver stage	P. falciparum	Peptide	[5 (link), 47 (link)]
SALSA 2	NGKDDVKEEKKTNEKKDDGKTDKVQEKVLEKSPKC	4019.52	Sporozoite and liver stage	P. falciparum	Peptide	[5 (link), 47 (link)
SR11.1	EEVVEELIEEVIPEELVLC	2213.5	Sporozoite and liver stage	P. falciparum	Peptide	[5 (link), 47 (link)]
LSA1-41	LAKEKLQEQQSDLEQERLAKEKLQEQQSDLEQERLAKEKEKLQC	5297.97	Liver stage	P. falciparum	Peptide	[5 (link), 6 (link), 48 (link)]
LSA1-J	ERRAKEKLQEQQSDLEQRKADTKKC	3046.43	Liver stage	P. falciparum	Peptide	[5 (link), 47 (link), 48 (link)]
LSA3-NR2	VLEESQVNDDIFNSLVKSVQQEQQHNVC	3230.53	Liver stage	P.falciparum	Peptide	[5 (link), 47 (link)]
LSA3-RE	VESVAPSVEESVAPSVEESVAENVEESVC	2991.2	Liver stage	P. falciparum	Peptide	[5 (link), 47 (link)]
PfMSPl-19	Glutathione S-transferase (GST) fusion protein. C-terminal expressed in E. coli		Merozoite	P. falciparum	Recombinant protein	[4 (link), 24 (link)]
GLURP	EDKNEKGQHEIVEVEEILC	2241.47	Trophozoite	P. falciparum	Peptide	[5 (link), 47 (link), 49 (link)]
GLURP-P3	EPLEPFPTQIHKDYKC	1945.23	Trophozoite	P. falciparum	Peptide	[5 (link), 47 (link), 50 (link)]
PfGLURP-R2	C-terminal produced in E. coli		Trophozoite	P. falciparum	Recombinant protein	[49 (link)]
Pvlike CSP	APGANQEGGAAAPGANQEGGAAAPGANQEGGAAC	2892.99	Sporozoite	P. vivax	Peptide	[47 (link)]
PvVK210 CSP	DGQPAGDRAAGQPAGDRADGQPAGDRADGQPAGC	3206.3	Sporozoite	P. vivax	Peptide	[47 (link), 51 (link), 52 (link)]
PvVK247 CSP	ANGAGNQPGANGAGNQPGANGAGNQPGANGAGNC	2905.95	Sporozoite	P. vivax	Peptide	[47 (link), 51 (link), 52 (link)]
PvCSP-chimera	Soluble His-tag protein expressed in wheat-germ cell free expression system		Sporozoite	P. vivax	Recombinant protein	[51 (link), 52 (link)]
PvAMAl			Merozoite	P. vivax	Recombinant protein	[53 (link), 54 ]
PvDBP			Merozoite	P. vivax	Recombinant protein	[55 (link)]
PvMSPl-19	C-terminal produced in the baculovirus expression system		Merozoite	P. vivax	Recombinant protein	[4 (link), 16 (link), 24 (link)]
PmCSP	GNAAGNAAGNDAGNAAGNAAGNAAGNAAGNAAC	2358.37	Sporozoite	P. malariae	Peptide	[47 (link)]
SALIV 1	EKVWVDRDNVYCGHLDCTRVATFC	2830.22	Salivary gland proteins	An. gambiae	Peptide	[5 (link), 56 (link)]
SALIV 2	ATFKGERFCTLCDTRHFCECKETREPLC	3324.84	Salivary gland proteins	An. gambiae	Peptide	[5 (link), 56 (link)]

Ags are organized according to the Plasmodium species and the life-cycle stages in the human host

Fig. 1

Overview of the study, indicating the antigens used in each step