Immunofluorescent Light Micrograph of a macrophage within brain tissue. Macrophages found in nervous tissue are termed microglia. At lower right, this large scavenger cell (stained red) moves in search of bacteria and other foreign invaders to ingest, playing an important role in the body's immune response. At centre, a tangle of neuron cells with interconnected nerve fibres stains green. Impulses travel through this tissue. Other non-conducting cells (glia) which form a supportive network, are also seen. Immunofluorescence is a staining technique which uses antibodies to attach fluores- cent dyes to specific tissues and molecules in the cell. Magnification x400 at 35mm, x750 at 6x4.5cm.