Table 1

WR99210 susceptibility of P. falciparum lines differing in their DHFR sequences and antifolate phenotypes

Strains^1-a	DHFR amino acid residue		WR99210 susceptibility
Strains^1-a	16	51	59	108	164	IC₅₀	IC₉₀
						nm
3D7	Ala	Asn	Cys	Ser	Ile	0.12 ± 0.01	0.19 ± 0.01
HB3 (PYR-R)	Ala	Asn	Cys	Asn	Ile	0.08 ± 0.01	0.12 ± 0.01
7G8 (PYR-R)	Ala	Ile	Cys	Asn	Ile	0.28 ± 0.02	0.62 ± 0.06
FCB (CYC-R)	Val	Asn	Cys	Thr	Ile	0.23 ± 0.03	0.62 ± 0.08
K1 (PYR-R)	Ala	Asn	Arg	Asn	Ile	0.71 ± 0.04	1.30 ± 0.06
Dd2 (PYR-R, CYC-R)	Ala	Ile	Arg	Asn	Ile	0.64 ± 0.04	1.39 ± 0.03
V1/S (PYR-R, CYC-R)	Ala	Ile	Arg	Asn	Leu	4.66 ± 0.08	14.32 ± 0.46

Values are mean ± standard deviation. Data shown are from a representative experiment that was performed in triplicate. Results were reproduced in two additional experiments. Three degrees of susceptibility to WR99210 were observed, namely the highly susceptible group of 3D7, HB3, 7G8, and FCB, the less susceptible group of K1 and Dd2 (characterized by the presence of the Arg59 residue), and the least susceptible, quadruple-mutant, parasite V1/S.

↵1-a PYR-R, pyrimethamine-resistant; CYC-R, cycloguanil-resistant.