[4)-alpha-D-Glcp-(1->4)-alpha-D-Galp-(1->4)-beta-D-GlcpA-(1->4)-beta-D-Glcp-(1->]n
[4)-alpha-d-glcp-(1->4)-alpha-d-galp-(1->4)-beta-d-glcpa-(1->4)-beta-d-glcp-(1->]n
A polysaccharide derivative comprising a tetrasaccharide repeating unit consisting of β-<small>D</small>-glucose, β-<small>D</small>-galactose, β-<small>D</small>-glucuronic acid and β-<small>D</small>-glucose residues all linked sequentially (1→4) and with the tetrasaccharide repeats themselves being linked (1→4); corresponds to the serotype 8 capsular polysaccharide (CPS) of <em>Streptococcus pneumoniae</em>.