REDUCTION OF ALLERGIC AIRWAY RESPONSES IN P-SELECTIN-DEFICIENT MICE

P-selectin is an adhesion receptor that has been shown to be important in the recruitment of eosinophils and lymphocytes in a variety of inf lammatory conditions. Because cellular recruitment is thought to be a critical event in allergen-induced changes in airway responsiveness, w e reasoned that P-selectin-deficient mice would exhibit reduced airway responsiveness and cellular trafficking noted in wild-type (+/+) mice . Both (+/+) and P-selectin-deficient (-/-) mice sensitized and challe nged with ovalbumin (OVA/OVA) exhibited the same capacity to produce i ncreased titers of total and OVA-specific immunoglobulin E. Airway res ponsiveness to methacholine was significantly greater in the (+/+) (OV A/OVA) animals than it was in the respective (-/-) (OVA/OVA) group or control groups (P = 0.0016). Bronchoalveolar lavage fluid from (-/-) ( OVA/OVA) mice contained significantly fewer eosinophils and lymphocyte s compared with the (+/+) (OVA/OVA) mice (P < 0.05). These results sug gest that the predominant role of P-selectin in OVA-induced airway hyp erresponsiveness is to promote the airway inflammatory response to all ergen inhalation.