Localization by Immunoelectron Microscopy of Schistosoma mansoni Antigens in the Glomerulus of the Hamster (Mesocricetus auratus) Kidney

Abstract

Adult worm antigen (AWA) and soluble egg antigen (SEA) were localized ultrastructurally by immunoelectron microscopy using two monoclonal antibodies in the glomeruli of hamsters infected with Schistosoma mansoni cercariae or injected with S. mansoni eggs. AWA was detected in all cercaria-infected groups from the 30th day on and was present mainly in cytoplasm of mesangial cells, mesangial matrix, and glomerular basement membrane, either as isolated gold particles or in small electron-dense deposits of probable immune origin. AWA was encountered also on the inner side of the glomerular basal membrane, close to endothelial cells, and in the foot processes of the glomerular epithelial cells. SEA was detected at similar sites, apparently in lesser amounts, in uninfected hamsters inoculated with S. mansoni eggs into the jugular vein. Schistosomal antigens are apparently processed mainly by mesangial cells which are considered to be critical in the pathogenesis of S. mansoni associated glomerulopathy. Mesangioproliferative glomerulonephritis, immunoglobulin (IgG and IgM), and C₃ deposits were observed in hamsters in which AWA and SEA were visualized. During early phases of the infection and in hamsters in which granulomatous pneumonitis was induced by S. mansoni eggs, glomeruli were unchanged or showed a slight mesangial proliferation. Our findings suggests that egg antigens also contribute to the pathogenesis of experimental glomerulopathy in the hamster.

Toxocaríase experimental em hamster

“…Esse aspecto já foi observado em algumas infecções parasitárias como esquistossomose (De Brito et al, 1998Nussensweig et al, 2002), leishmaniose visceral , e outras infecções parasitárias Florquin, 2000).…”

“…No modelo de hamster a glomerulonefrite mesangioproliferativa não foi difusa, e sim focal, diferindo de outras doenças crônicas como esquistossomose e leishmaniose visceral De Brito et al, 1998), e os depósitos de imunoglobulinas foram geralmente segmentares no glomérulo.…”

“…The establishment of a glomerulopathy associated with a parasitic infection requires persistent antigenic presentation to the kidneys, usually over a period of years, as in schistosomiasis (De Brito et al 1998 and less frequently in visceral leishmaniasis ) and other parasitic diseases (van Velthuysen and Florquin 2000). Nonspecific mesangioproliferative glomerulonephritis, with glomerular IgM-IgG and C3 usually detected by IF, is probably the most frequent pattern of parasitic-associated glomerulopathy.…”

“…Immunoelectron microscopy Immunoelectron microscopy was performed essentially as described elsewhere (De Brito et al 1998 using the monoclonal antibody, B6C3. The kidneys of 17 hamsters were used, corresponding to 4 days (2 kidneys), 6 days (2 kidneys), 10 days (3 kidneys), 15 days (5 kidneys), and 30 days (5 kidneys) after infection.…”

“…A técnica de imunomarcação com proteína A ouro por microscopia eletrônica, foi realizada como descrita previamente por De Brito et al (1998 …”