Structure-immunomodulating activity relationships of a pectic arabinogalactan from Vernonia kotschyana Sch. Bip. ex Walp.

After removal of the galacturonan moiety and partial degradation of the neutral side chains attached to the rhamnogalacturonan backbone the remains of the pectic arabinogalactan still expressed potent complement fixation and B-cell mitogenic activity. Bioactive sites seem to be located both in the peripheral parts of the molecule and also in the inner core of the enzyme resistant ramified region.