HETEROGENEOUS DOLICHOS-BIFLORUS LECTIN-BINDING TO A SUBSET OF RAT ALVEOLAR MACROPHAGES IN NORMAL AND FIBROTIC LUNG-TISSUE

The distribution of Dolichos biflorus lectin in the rat lung and during fibrosis after irradiation was investigated by lectinhistochemical and electronmicroscopical techniques and double immunofluorescence labelling with the monoclonal antibodies RM-1 and ED-1. The results indicate a selective reaction of Dolichos biflorus lectin with a subpopulation of alveolar macrophages. No binding of the lectin was detectable in ED-1-positive macrophages but strong staining occurred in a part of the RM-1-positive cell population. In fibrotic lung specimens an increased number of Dolichos biflorus lectin-positive macrophages was found in which focally ED-1 reactive and RM-1 negative cells appeared. The finding of changing lectin binding pattern in a radiation-induced lung model emphasizes the suitability of the Dolichos biflorus lectin as a marker of macrophage activation or functional specialization.