Variation in the Expression of Macrophage Fc_ε Receptors in Relation to Experimental Rat Schistosome Infection

Abstract

The relationship between IgE and rat peritoneal macrophages during the course of Schistosoma mansoni infection was examined. Immune macrophages exhibited an IgE-dependent schistosomulicidal activity mainly between the 5th and the 7th weeks. At this period the percentages of anti-lgE rosettes whose variations appeared consecutive to the variations in the serum IgE level were higher. Following incubation in a serum-free medium immune macrophages could release membrane-associated IgE, to a certain extent, and consequently formed rosettes with IgE-coated erythrocytes, indicating the existence of Fc_ε receptors. Thus, in terms of rosettes, their number varied in the course of the disease. In fact IgE-rich serum (i.e. at day 42) as IgE molecules could induce this macrophage Fc_ε receptor. Moreover when transferred to syngeneic rats in associaton with parasite-specific IgE Fc_ε R₂⁺ macrophages led to some protection against challenge infection. All the data reported here emphasize the determining role of macrophages and IgE in immunity to schistosomiasis.