THE EFFECT OF HEPARIN AND RELATED PROTEOGLYCANS ON ALLERGEN AND PAF-INDUCED EOSINOPHIL INFILTRATION

Exposure of normal guinea pigs to an aerosol of PAF induced a selectiv e increase in the percentage of eosinophils in bronchoalveolar lavage (BAL) fluid 24 h after challenge. Challenge of actively sensitised gui nea pigs with an aerosol of ovalbumin also induced a selective increas e in the percentage of eosinophils recovered in BAL fluid 24 h post ch allenge. Pretreatment of actively sensitised guinea pigs or normal gui nea pigs with unfractionated heparin significantly reduced such eosino phil infiltration induced by allergen or PAF challenge respectively, a lthough higher amounts of heparin were required to inhibit antigen ind uced eosinophil infiltration. Similar effects were also observed follo wing treatment with the low molecular weight heparin-like material ORG 10172 but not the anionic molecule polyglutamic acid or high molecula r weight dextrans. These results suggest that proteoglycans may posses s anti-allergic activity that is not necessarily related to either suc h molecules being anionic in nature nor to anti-coagulant activity.