Journal Article

Enzymatically deglycosylated human IgA1 molecules accumulate and induce inflammatory cell reaction in rat glomeruli

Takashi Sano, Yoshiyuki Hiki, Tohru Kokubo, Hitoo Iwase, Hidekazu Shigematsu and Yutaka Kobayashi

in Nephrology Dialysis Transplantation

Published on behalf of European Renal Association - European Dialysis and Transplant Assoc

Volume 17, issue 1, pages 50-56
Published in print January 2002 | ISSN: 0931-0509
Published online January 2002 | e-ISSN: 1460-2385 | DOI: http://dx.doi.org/10.1093/ndt/17.1.50
Enzymatically deglycosylated human IgA1 molecules accumulate and induce inflammatory cell reaction in rat glomeruli

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Background. Previously, we have been able to isolate IgA1 from IgA nephropathy (IgAN) patients, that could accumulate in rat glomeruli (glomerulophilic IgA1). The ‘glomerulophilic IgA1’ was determined to be under‐O‐glycosylated in its hinge region, suggesting that under‐O‐glycosylation in the IgA1 hinge region plays a role in its glomerular deposition in IgAN. To confirm this, the accumulation of enzymatically under‐glycosylated IgA1 in rat kidney was examined.

Methods. Human IgA1 was isolated from healthy individuals by Jacalin‐affinity chromatography. Desialylated (deS IgA1) or further degalactosylated IgA1 (deS/deGal IgA1) molecules were then prepared using neuraminidase and β‐galactosidase. Two or five mg of IgA1 were injected into the left renal artery of Wistar rats. The rats were sacrificed at various time intervals (3, 9, 24 h) and the perfused part of the renal cortex was removed for immunofluorescence and for light and electron microscopy.

Results. Distinct amounts of deS IgA1 and deS/deGal IgA1 were observed in rat glomeruli. On the other hand, untreated IgA1 molecules (native IgA1) did not show any obvious accumulation. In rats injected with under‐glycosylated IgA1, accumulation of polymorphonuclear cells (PMN) was also observed.

Conclusions. These results confirmed that under‐glycosylation of IgA1 played an important role in the glomerular accumulation of IgA1, which was followed by infiltration of PMN into glomeruli.

Keywords: glomerulophilic IgA; IgA nephropathy; inflammatory cell reaction; under‐glycosylated IgA1

Journal Article.  3273 words.  Illustrated.

Subjects: Nephrology

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