Objective of the present invention is to provide polysaccharides which modulate immune response, and which can be used as ingredients in edible products or pharmaceutical compositions. The present invention provides such polysaccharides obtained from the species Camellia sinensis, which comprise a rhamnogalacturonan-I core, and wherein the molar ratio of galacturonyl acid residues to rhamnosyl residues in the backbone of the polysaccharide is close to 1:1. The present invention also provides edible products or pharmaceutical compositions containing such polysaccharides, in order to modulate immune response.
