Is tolerance induction a possible mode of action of OM-89?

Neonatal Wistar rats were injected intraperitoneally with either 20 mu g OM-89 at birth and on day 3 after birth or 2 mg three times weekly until 200 g body weight. At this weight, groups were either implanted subcutaneously with a cotton pellet to induce granuloma, or had avridine polyarthritis or pleurisy induced. Both OM-89 treatment regimes significantly reduced granuloma weight (p < 0.05 and < 0.01), paw volume (p < 0.001) and pleural exudates (p < 0.01). The results suggest that OM-89 could work via tolerance induction.