Avaliação de JBE (“Jacalin Binding Exoantigen”- Exoantígeno Ligante de Jacalina) na fagocitose de leveduras de Paracoccidioides brasiliensis por macrófagos peritoneais murinos

Abstract

Paracoccidioides brasiliensis has antigenic components on surface able to promote the interaction between fungus and host, and promote the infection. In the present study the presence of JBE (Jacalin Binding Exoantigen) in culture supematant of BAT P. brasiliensis isolate and on yeast cells were verified and the effect of JBE in attachment to murine peritoneal macrophages was investigated. JBE was obtained in yeast cells culture supematant (liquid F-10 médium containing 0.5 % D-Glucose) and showed by SDS-PAGE and silver nitrate staining a 190 kDa component and, under reducing conditions, a 70 kDa component. Moreover, JBE was localized by rabbit anti-gpl90 IgG and immunogold reaction on yeast cells surface. Peritoneal macrophages form BALB/c mice were treated with JBE (50 e 100 pg/mL) and incubated with P. brasiliensis yeast cells FITC labelling pre-treated with 50 mM monosaccharides: N-acetyl-D-glucosamine (GlcNAc), or D-Glucose, or D-Galactose or D-Mannose. JBE was able to promote phagocytosis inhibition (40 %) and NO release by JBE-treated macrophages. The phagocytosis inhibition increased to 64 % when JBE-treated macrophages were incubated with yeast cells pre-treated with GlcNAc, though NO release was decreased. Yeast cells were treated with mice anti-JBE IgG F(ab) polyclonal fragments (50 e 100 pg/mL) and macrophages treated with 50 mM monosaccharides promoted phagocytosis inhibition, the incubation of both promoted a increase on phagocytosis inhibition. The incubation of JBE-treated macrophages (50 pg/mL) and yeast cells pre-treated with anti-JBE IgG F(ab) (50 pg/mL) promoted phagocytosis inhibition (61,5 %). This results suggest that JBE could be involved on the fungus and host interaction because its localization. Furthermore, JBE potentializes the phagocytosis of P. brasiliensis yeast cells by murine peritoneal macrophages. Probably, the phagocytosis inhibition and NO decrease by GlcNAc is due to gp 70 affinity to GlcNAc. The anti-JBE IgG F(ab) probably occupies sites of interaction on yeast cells and improve the phagocytosis inhibition by monosaccharides or JBE on macrophages. In conclusion, JBE has component able to promote invasion of fungus.