FUNCTIONAL BETA-GLUCAN RECEPTOR EXPRESSION BY A MICROGLIAL CELL-LINE

In the central nervous system, the functions of microglia appear cruci al after brain damage, when phagocytes eliminate cell debris, acting a s the scavengers of the brain. Diseases where an active role for micro glia has been proposed recently include Alzheimer's disease, the acqui red immune deficiency syndrome (AIDS) and multiple sclerosis. Only rec ently has it been possible to obtain a microglial cell line retaining morphological and functional aspects of these cells and their secretor y products. Sugar receptors are expressed by a variety of phagocytes i n primary cultures, but in contrast, are absent on the majority of the described macrophage-like cell lines. We here establish, by 4 degrees C binding experiments, that this murine cell line, called BV-2, expre sses a high level (9.86 +/- 0.91 x 10(5); n = 3) of beta-glucan recept ors. At 37 degrees C, BV-2 cells show high phagocytic power that can o nly be inhibited by the free polysugar beta-laminarin (a poly-glucose) and not by mannan (a poly-mannose) as described for macrophages. The beta-glucan receptor expressed by the microglial cell line BV-2 is ful ly functional in phagocytosis of unopsonized heat-killed yeast particl es.