RRC ID 46982
Author Vivan RH, Leonello PC, Nagashima LA, Kaminami MS, Tristão FS, Sano A, Ono MA, Béjar CV, Itano EN.
Title Soluble components of Histoplasma capsulatum var. capsulatum have hemagglutinin activity and induce syngeneic hemophagocytosis in vitro.
Journal Mycopathologia
Abstract Histoplasma capsulatum var. capsulatum is a thermally dimorphic fungus that causes histoplasmosis. Fungal hemagglutination activity and cases of reactive hemophagocytic syndrome (RHS) have been reported in the disseminated form of disease. In the present study, soluble components of H. capsulatum var. capsulatum have been investigated for hemagglutinin activity and the capacity to induce hemophagocytosis in the mouse system. To analyze hemagglutinating activity, mouse red blood cells (RBC) (1% v/v in PBS) were incubated (37 degrees C, 1 h) with cell-free antigen (CFAg) from H. capsulatum var. capsulatum (isolate IMT/HC128) (RBC-CFAg) or previously heated CFAg (56 degrees C, 30 min) (RBC-hCFAg) or as control with PBS (RBC-PBS). Hemophagocytosis was analyzed by incubating BALB/c mouse peritoneal phagocytic cells (5 x 10(6) cells) with syngeneic RBC, sensitized or not with CFAg. In addition, mouse polyclonal antibodies were raised against syngeneic RBC-CFAg (anti-RBC-CFAg) and used to analyze CFAg chromatographic fractions (Sephadex G75/120) by immunoenzymatic assay (ELISA). Hemagglutinin activity was observed with RBC-CFAg, but not with RBC-hCFAg or RBC. Also, hemophagocytosis was observed with RBC-CFAg, but not with RBC. The anti-RBC-CFAg antibodies reacted with CFAg fractions corresponding to a molecular mass (MM) higher than 150 kDa. In conclusion, the yeast form of H. capsulatum var. capsulatum releases thermolabile soluble components with hemagglutinin activity and it has been demonstrated for the first time that soluble components of the same fungus induce syngeneic hemophagocytosis in the in vitro mouse system. Also, indirect analysis with antibodies suggests that high-MM components (>150 kDa) are responsible for the interaction with RBC.
Volume 169(3)
Pages 151-7
Published 2010-3-1
DOI 10.1007/s11046-009-9243-3
PMID 19908162
MeSH Animals Enzyme-Linked Immunosorbent Assay Fungal Proteins / chemistry Fungal Proteins / immunology* Fungal Proteins / isolation & purification* Hemagglutination* Histoplasma / chemistry* Macrophages, Peritoneal / immunology Mice Mice, Inbred BALB C Molecular Weight Phagocytosis*
IF 2.452
Times Cited 3
Pathogenic microorganisms