Effect of mannuronate content and molecular weight of alginates on intestinal immunological activity through Peyer's patch cells of C3H/HeJ mice

We studied the effect of the mole fraction (FM) of β-d-mannuronate residues in alginate chains and the weight-average molecular weight (Mw) of alginates on intestinal immunological activity through Peyer's patch cells of C3H/HeJ mice. Over most of the range of Mw (30,000–690,000), alginates with high mannuronate content (high-M alginates, FM 0.69–0.86) showed immunological activity, but alginates with FM lower than 0.31 did not. For high-M alginates with FM = 0.78 extracted from Laminaria japonica, those with Mw lower than 200,000 showed the highest activity.