Phagocytosis of nonopsonized Cryptococcus neoformans by swine microglia involves CD14 receptors

The interaction of the opportunistic fungus Cryptococcus neoformans with swine microglia was studied in vitro in the presence and absence of anti- CD14 monoclonal antibodies. In the absence of anti-CD14 antibodies, 36% of microglia had phagocytized nonopsonized, encapsulated cryptococci after 2 hr incubation (effector-to-target ratio, 1:50). Preincubation of microglia with anti-CD14 antibodies resulted in a 63% reduction of phagocytosis. These findings suggest that CD14 receptors facilitate uptake of nonopsonized C. neoformans by resident macrophages within the brain.