MONOCYTE AGGREGATION AROUND AGAROSE BEADS IN COLLAGEN GELS - A 3-DIMENSIONAL MODEL OF EARLY GRANULOMA-FORMATION

Granulomas consist of organised collections of macrophages showing evi dence of activation in response to an agent localised within a tissue. To date, in vitro models of granuloma formation have failed to reprod uce the histological appearance of a granuloma, which forms a characte ristic three-dimensional structure. The use of 3-D collagen gels allow s agarose beads and human mononuclear cells to be suspended together i n a milieu which permit the two to interact. The interaction between a garose beads and mononuclear cells produces monocyte-macrophage aggreg ates within 24 h which resemble an early, granuloma. The monocytes sho w evidence of activation by direct microscopy, electron microscopy and immunohistochemistry. This model should permit the laboratory testing of hypotheses describing granuloma formation.