We applied anti-ICAM-1 and anti-LFA-1 monoclonal antibody (mAb) to ovalbumin-sensitized rats and examined the effects on nasal eosinophilia and nasal symptoms following topical antigen challenge. In a general and local immunization (GLI) group of rats, the mAbs were applied during the booster topical immunization period. In a general immunization group and a local immunization (LI) group of rats, the mAbs were applied during the immunization period. The number of sneezes and nasal scratching movements occurring soon after topical antigen (Ag) challenge was significantly suppressed in the GLI and LI group rats. Eosinophil infiltration into nasal mucosa 24 h after Ag challenge was also significantly suppressed in GLI and LI group rats. These findings suggest that the ICAM-1/LFA-1 system is important in topical allergic inflammation in rats.