Development of a protein array platform for profiling antibody responses to P. vivax infection. (A) Left panel. Different concentrations of rPvCSP were probed with pooled human serum (left duplicate, negative serum; right duplicate, positive serum). Right panel. rPvCSP (6 ng/μl) reacted with individual serum samples in duplicates. Left phase of slide: vivax negative serum samples; Right phase of two slides: vivax positive serum samples. Red bar, pooled positive sera reacted with rPvCSP; Green bar, pooled vivax negative sera reacted with rPvCSP; Yellow bar, 10 OD wheat germ extract reacted with rPvCSP. NM: negative P. vivax patient sera mixture; PM: positive P. vivax patient sera mixture; N: individual negative serum; P: individual positive serum. (B) Correlation between spot intensities and the concentration of rPvCSP.