DISTRIBUTION OF MACROPHAGE LINEAGE CELLS IN RAT GINGIVAL TISSUE AFTERTOPICAL APPLICATION OF LIPOPOLYSACCHARIDE - AN IMMUNOHISTOCHEMICAL STUDY USING MONOCLONAL-ANTIBODIES - OX6, ED1 AND ED2

To discuss the role of macrophage lineage cells on the periodontal tis sue destruction, we immunohistochemically examined the phenotype and t he dynamics of macrophage lineage cells 1 or 3 h or 1, 2, 3 or 7 d aft er topical application of LPS (5 mg/ml in physiological saline) from t he rat gingival sulcus using 3 monoclonal antibodies: OX6 (antigen-pre senting cells), ED1 (monocytes, macrophages and dendritic cells) and E D2 (resident macrophages). We could detect at least 3 different types of macrophage lineage cells, namely OX6(+)/ED1(+)/ED2(-) dendritic cel ls and exudate macrophages and ED2(+) resident macrophages. After LPS application the majority of macrophage lineage cells accumulated in th e subjunctional epithelial area were newly extravasated OX6(+)/ED1(+)/ ED2(-) dendritic cells or macrophages. The number of these cells incre ased progressively with time and reached a maximum level at d 2, On th e other hand, number and tissue distribution of ED2(+) resident macrop hages did not change. These results indicate that several types of mac rophage lineage cells exist in rat gingival tissue and suggest that de ndritic cells and exudate macrophages transiently accumulated after LP S application are responsible for various host immune response and tis sue destruction caused by LPS.