Abstract
The mechanism of mesangial IgA deposition is poorly understood in IgA nephropathy (IgAN). Abnormal glycosylation of carbohydrate moieties in the hinge region of the IgA molecule has recently attracted much attention. In this report, we studied galactosylation and sialylation profiles in κ‐ and λ‐IgA1 from patients with IgAN. Total serum IgA1 was isolated from patients with IgAN or healthy controls by jacalin‐affinity chromatography. Six fractions of molecular weight (MW) 50–1,000 kDa were separated by fast protein liquid chromatography (FPLC). Four lectin‐binding assays were used to study the sialylation and the presence of terminal galactose or N‐acetylgalactosamine (GalNAc) in the O‐linked carbohydrate moieties of κ‐ or λ‐IgA1. Maackia amurensis agglutinin (MAA) and Sambucus nigra agglutinin (SNA) lectin recognize α(2,3)‐ and α(2,6)‐linked sialic acid, respectively. Peanut agglutinin (PNA) and Helix aspersa (HA) lectin recognize terminal galactose and GalNAc, respectively. Reduced HA was demonstrated in macromolecular κ or λ‐IgA1 (300–825 kDa) isolated from patients with IgAN (P < 0.05 compared with healthy controls). Lambda‐ but not κ‐IgA1 from patients with IgAN bound less to PNA (P < 0.05). The α(2,3)‐linked sialic acid content in λ‐ but not κ‐IgA1 of MW 150–610 kDa from patients was higher than that of controls (P < 0.005). The α(2,6)‐linked sialic acid content in λ‐IgA1 (300–825 kDa) and κ‐IgA1 (150–610 kDa) from patients was also higher than that of controls. This unusual glycosylation and sialylation pattern of the λ‐IgA1 may have important implications for the pathogenesis of IgAN, as both the masking effect of sialic acid on galactose and the reduced galactosylation will hinder the clearance of macromolecular λ‐IgA1 by asialoglycoprotein receptor of hepatocytes. The negative charge from sialic acid may also favor mesangial deposition of macromolecular λ‐IgA1 in IgAN. J. Clin. Lab. Anal. 16:11–19, 2002. © 2002 Wiley‐Liss, Inc.
Keywords: IgA nephropathy, glycosylation, sialylation, IgA1, polymeric IgA, λ‐IgA
REFERENCES
- 1. López‐Trascaca M, Egido J, Sancho J, Hernando L. 1980. IgA glomerulonephritis (Berger’s disease): evidence of higher serum levels of polymeric IgA. Clin Exp Immunol 42:247–254. [PMC free article] [PubMed] [Google Scholar]
- 2. Lai KN, Lai FM, Chui SH, et al. 1987. Studies of lymphocyte subpopulations and immunoglobulin production in IgA nephropathy. Clin Nephrol 28:281–287. [PubMed] [Google Scholar]
- 3. Sakai H, Nomoto Y, Arimori S, Komori K, Inouye H, Tsuji K. 1979. Increase of IgA‐bearing peripheral blood lymphocytes in the families of patients with IgA nephropathy. Am J Clin Pathol 72:452–456. [DOI] [PubMed] [Google Scholar]
- 4. Schena FP, Mastrolitti G, Fracasso AR, Pastore A, Ladisa N. 1986. Increased immunoglobulin‐secreting cells in the blood of patients with active idiopathic IgA nephropathy. Clin Nephrol 26:163–168. [PubMed] [Google Scholar]
- 5. Egido J, Sancho J, Mampaso F, et al. 1980. A possible common pathogenesis of the mesangial IgA glomerulonephritis in patients with Berger disease and Schönlein‐Henoch syndrome. Proc Eur Dial Transpl Assoc 17:660–666. [PubMed] [Google Scholar]
- 6. Valentijn R, Radl J, Haaijman J, et al. 1984. Circulating and mesangial secretory component‐binding IgA1 in primary IgA nephropathy. Kidney Int 26:760–766. [DOI] [PubMed] [Google Scholar]
- 7. Isaac KL, Miller F. 1982. Role of antigen size and charge in immune complex glomerulonephritis. Lab Invest 2:198–205. [PubMed] [Google Scholar]
- 8. Lai KN, Chui SH, Lewis WHP, Poon ASY, Lam CWK. 1994. Charge distribution of lambda‐IgA in IgA nephropathy. Nephron 66:38–44. [DOI] [PubMed] [Google Scholar]
- 9. Mestecky J, McGhee JR. 1987. Immunoglobulin A (IgA): molecular and cellular interaction involved in IgA biosynthesis and immune response. Adv Immunol 40:143–245. [DOI] [PubMed] [Google Scholar]
- 10. Andre PM, Le Pogamp P, Chevet D. 1990. Impairment of jacalin binding to serum IgA in IgA nephropathy. J Clin Lab Anal 4:115–119. [DOI] [PubMed] [Google Scholar]
- 11. Allen AC, Harper SJ, Feehally J. 1995. Galactosylation of N‐ and O‐linked carbohydrate moieties of IgA1 and IgG in IgA nephropathy. J Clin Immunol 100:470–474. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 12. Hiki Y, Horii A, Iwase H. 1995. O‐linked oligosaccharide on IgA1 hinge region in IgA nephropathy. Contrib Nephrol 111:73–84. [PubMed] [Google Scholar]
- 13. Mestecky J, Tomana M, Crowley‐Nowick PA, Moldoveanu Z, Julian B, Jackson S. 1993. Defective galactosylation and clearance of IgA1 molecules as a possible etiopathogenic factor in IgA nephropathy. Contrib Nephrol 104:172–182. [DOI] [PubMed] [Google Scholar]
- 14. Lai KN, To WY, Li PKT, Leung JCK. 1996. Increased binding of polymeric λ‐IgA to cultured human mesangial cells in IgA nephropathy. Kidney Int 49:839–845. [DOI] [PubMed] [Google Scholar]
- 15. Leung JCK, Poon PYK, Lai KN. 1999. Increased sialylation of polymeric immunoglobulin A1: mechanism of selective glomerular deposition in immunoglobulin A nephropathy? J Lab Clin Med 133:152–60. [DOI] [PubMed] [Google Scholar]
- 16. To WY, Leung JCK, Lai KN. 1995. Identification and characterization of human serum alpha2‐HS glycoprotein as a jacalin‐bound protein. Biochim Biophys Acta 1249:58–64. [DOI] [PubMed] [Google Scholar]
- 17. Monteiro RC, Halbwachs‐Mecarelli L, Berger J, Lesavre P. 1984. Characteristics of eluted IgA in primary IgA nephropathy. Contrib Nephrol 40:107–111. [DOI] [PubMed] [Google Scholar]
- 18. Baharaki D, Dueymes M, Perrichot R, et al. 1996. Aberrant glycosylation of IgA from patients with IgA nephropathy. Glycoconj J 13:505–511. [DOI] [PubMed] [Google Scholar]
- 19. Hiki Y, Tanaka A, Kokubo T, et al. 1998. Analyses of IgA1 hinge glycopeptides in IgA nephropathy by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry. J Am Soc Nephrol 9:577–582. [DOI] [PubMed] [Google Scholar]
- 20. Mestecky J, Hashim OH, Tomana M. 1995. Alternation in the IgA carbohydrate chains influence the cellular distribution of IgA1 . Contrib Nephrol 111:65–71. [DOI] [PubMed] [Google Scholar]
- 21. Allen AC. 1995. Abnormal glycosylation of IgA: is it related to the pathogenesis of IgA nephropathy? Nephrol Dial Transplant 10:1121–1123. [PubMed] [Google Scholar]
- 22. Basset C, Durand V, Jamin C, et al. 2000. Increased N‐linked glycosylation leading to oversialylation of monomeric immunoglobulin A1 from patients with Sjogren’s syndrome. Scand J Immunol 51:307–311. [DOI] [PubMed] [Google Scholar]
- 23. Stockert RJ, Kressner MS, Collins JC, Sternlieb I, Morell AG. 1982. IgA interaction with the asialoglycoprotein receptor. Proc Natl Acad Sci U S A 79:6229–6231. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 24. Tomana M, Kulhavy R, Mestecky J. 1988. Receptor mediated binding and uptake of immunoglobulin A by human liver. Gastroenterology 94:762–770. [DOI] [PubMed] [Google Scholar]
- 25. Gomez‐Guerrero C, Gonzalez E, Egido J. 1993. Evidence for a specific IgA receptor in rat and human mesangial cells. J Immunol 151:7172–7181. [PubMed] [Google Scholar]
- 26. Odani H, Hiki Y, Takahashi M, et al. 2000. Direct evidence for decreased sialylation and galactosylation of human serum IgA1 Fc O‐glycosylated hinge peptides in IgA nephropathy by mass spectrometry. Biochem Biophys Res Commun 271:268–274. [DOI] [PubMed] [Google Scholar]
- 27. Delacroix DL, Dive C, Rambaud JC, Vaerman JP. 1982. IgA subclasses in various secretions and in serum. Immunology 47:383–385. [PMC free article] [PubMed] [Google Scholar]
- 28. Mattu TS, Pleass RJ, Willis AC, et al. 1998. The glycosylation and structure of human serum IgA1, Fab, and Fc regions and the role of N‐glycosylation of Fcα receptor interactions. J Biol Chem 273:2260–2272. [DOI] [PubMed] [Google Scholar]
- 29. Greer MR, Barratt J, Harper SJ, Allen AC, Feehally J. 1998. The nucleotide sequence of the hinge region of IgA1 in IgA nephropathy. Nephrol Dial Transplant 13:1980–1983. [DOI] [PubMed] [Google Scholar]
- 30. Allen AC, Topham PS, Harper SJ, Feehally J. 1997. Leucocyte β1,3 galactosyltransferase activity in IgA nephropathy. Nephrol Dial Transplant 12:701–706. [DOI] [PubMed] [Google Scholar]
- 31. Monteiro RC, Halbwachs‐Mecarelli L, Roque‐Barreira MC, Noel LH, Berger J, Leavre P. 1985. Charge and size of mesangial IgA in IgA nephropathy. Kidney Int 28:666–671. [DOI] [PubMed] [Google Scholar]
- 32. Monteiro RC, Chevailler A, Noel LH, Leavre P. 1988. Serum IgA preferentially binds to cationic polypeptides in IgA nephropathy. Clin Exp Immunol 73:300–306. [PMC free article] [PubMed] [Google Scholar]
- 33. Gallo GR, Caulin‐Glaser T, Emancipator SN, Lamm ME. 1983. Nephritogenicity and differential distribution of glomerular immune complexes related to immunogen charge. Lab Invest 48:353–362. [PubMed] [Google Scholar]
- 34. Leung JCK, Tang SCW, Lam MF, Chan TM, Lai KN. 2001. Charge dependent binding of polymeric IgA1 to human mesangial cells in IgA nephropathy. Kidney Int 59:277–285. [DOI] [PubMed] [Google Scholar]