Inhibition of P. falciparum IRBC binding to CSPG by C4S oligosaccharides containing different ratio of sulfated and non-sulfated disaccharides. Inhibition with oligosaccharides (see Figure 5 and Table 2)) was performed two times each in duplicate and the results are presented as mean + SEM. ●, partially sulfated C4S containing 35% 4-sulfated, 65% non-sulfated disaccharides; ○, oligosaccharide III-F26c; σ, oligosaccharide III-F27d; Δ, oligosaccharide III-F28c; ▪, oligosaccharide III-F27b; ■, oligosaccharide III-F26b; x, fully 4-sulfated C4S dodecasaccharide (12 mer-6S prepared by testicular hyaluronidase digestion of fully 4-sulfated CS). Fractions III-F25c, III-F27c, III-F28b and IIIF28d outlined in Table 2 were also analyzed and they exhibited maximum inhibitory activity (not shown). The inhibitory activity of 12 mer with 2S is similar to that of the partially 4-sulafted C4S shown in closed circle.