[6)-[beta-D-Galp-(1->2)]-alpha-D-Galp-(1->3)-beta-L-Rhap2Ac-(1->4)-beta-D-Glcp-(1->3)-[alpha-D-GlcpNAc-(1->2)-alpha-L-Rhap-(1->4)]-beta-D-GalpNAc-(1->]n
[6)-[beta-d-galp-(1->2)]-alpha-d-galp-(1->3)-beta-l-rhap2ac-(1->4)-beta-d-glcp-(1->3)-[alpha-d-glcpnac-(1->2)-alpha-l-rhap-(1->4)]-beta-d-galpnac-(1->]n
A polysaccharide derivative with a repeating unit consisting of α-<small>D</small>-galactosyl, 2-<em>O</em>-acetyl-β-<small>L</small>-rhamnosyl, β-<small>D</small>-glucosyl and <em>N</em>-acetyl-β-<small>D</small>-galactosaminyl residues linked sequentially (1→3), (1→4) and (1→3), to the galactosyl and <em>N</em>-acetyl-β-<small>D</small>-galactosaminyl residues of which are attached respectively a β-<small>D</small>-galactosyl residue and an <em>N</em>-acetyl-α-<small>D</small>-glucosaminyl-(1→2)-α-<small>L</small>-rhamnosyl disaccharide unit via (1→2) and (1→4) linkages respectively, with all repeating units being linked (1→6). The repeating unit corresponds to that of the capsular polysaccharide of <em>Streptococcus pneumoniae</em> serotype 7F (ST7F).