Functional beta-glucan receptor expression by a microglial cell line.

In the central nervous system, the functions of microglia appear crucial after brain damage, when phagocytes eliminate cell debris, acting as the scavengers of the brain. Diseases where an active role for microglia has been proposed recently include Alzheimer's disease, the acquired immune deficiency syndrome (AIDS) and multiple sclerosis. Only recently has it been possible to obtain a microglial cell line retaining morphological and functional aspects of these cells and their secretory products. Sugar receptors are expressed by a variety of phagocytes in 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, expresses a high level (9.86 +/- 0.91 x 10(5); n = 3) of beta-glucan receptors. At 37 degrees C, BV-2 cells show high phagocytic power that can only 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 fully functional in phagocytosis of unopsonized heat-killed yeast particles.