Inhibition of P. falciparum IRBC binding to CSPG by Δ-oligosaccharide fractions. Δ-Oligosaccharide subfractions obtained by HPLC (Figure S2 of the supporting information) and characterized by mass spectrometry (Table 2) were analyzed for inhibition of IRBC binding to placental CSPG as outlined in Figure 1. Analysis was performed two times each in duplicates and the results are presented as mean + SEM. λ, partially sulfated C4S containing 35% 4-sulfated, 65% non-sulfated; ○, dodecasaccharide with unmodified GlcA at the nonreducing end (12 mer-2S in Figure 3); σ,Δ-dodecasaccharide (III-F29c);Δ, decasaccharide with unmodified GlcA at the nonreducing end (sample previously prepared from bovine tracheal C4S, Ref. 17); ■, Δ-decasaccharides obtained by S. dysgalactiae hyaluronidase digestion of C4S with 14% 4-sulfate followed by Bio-Gel P-6 chromatography.