Circulating Serum Lectins of Patients with IgA Nephropathy Stimulate IL-6 Release from Mesangial Cells

Carmelo Libetta, Teresa Rampino, Giuseppe Palumbo, Ciro Esposito, Antonio Dal Canton

Research output: Contribution to journalArticle

Abstract

Previously, the authors reported that the serum of patients with immunoglobulin (Ig) A nephropathy stimulated peripheral leukocytes, and this effect was inhibited by nominal haptens for lectins. In vitro studies have shown that lectins can bind to rat mesangial cells and cause their activation. This study was performed to investigate whether the serum of IgA nephropathy patients contains lectins that activate mesangial cells, i.e., induce release of interleukin (IL)-6, a nephritogenic cytokine. The serum of patients was adsorbed by affinity chromatography on resins loaded with lectin-binding sugars. After adsorption, serum supernatant was collected and the resins were then eluted. Human mesangial cells were conditioned with native serum, post-adsorption supernatant, and eluate (all three at 10%) for 24 h, and the release of IL-6 was determined by ELISA. Normal serum was used as control. Incubation of mesangial cells with IgA nephropathy patients' serum raised average IL-6 release from 8.5 pg/mL to 274.1 pg/mL. Adsorption in β-D-glucose and N-acetyl-D-glucosamine caused a fall in the activity of patients' serum, to 17.0 and 63.7 pg/mL, respectively, and the activity lost was recovered in the eluate (185.2 and 142.7 pg/mL, respectively). Neither adsorption on N-acetyl-D-galactosamine nor on fucosylamine was associated with any effect on serum activity; accordingly, no activity was found in the eluates. Serum of patients with non-IgA mesangiocapillary nephritis did not stimulate mesangial cells. These results show that the serum of IgA nephropathy patients contains specific lectins that stimulate IL-6 release by mesangial cells and are, therefore, potentially nephritogenic.

Original languageEnglish
Pages (from-to)208-213
Number of pages6
JournalJournal of the American Society of Nephrology
Volume8
Issue number2
Publication statusPublished - Feb 1997

ASJC Scopus subject areas

  • Nephrology

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