Induction of anti-Ro60/anti-La by immunisation with spectrin and induction of anti-spectrin by immunisation with Ro60 and 4-hydroxy-2-nonenal-modified Ro60 immunisation.

Abstract

OBJECTIVES:

The Ro ribonucleoprotein particle, targeted in systemic lupus erythematosus (SLE) and Sjögren's syndrome (SS), includes Ro60 (SSA) and La (SSA) autoantigens. Anti-Ro60 occurs in SLE and SS. The importance of α-fodrin and spectrin as well as anti-Ro and anti-fodrin/spectrin antibodies in SS and SLE, led us to hypothesise that rabbit immunisation with Ro60 or 4-hydroxy-2-nonenal-modified Ro60 would induce anti-spectrin. In addition, we hypothesised that antibodies to Ro60 and La will develop in animals immunised with spectrin.

METHODS:

Two NZW rabbits each were immunised with 4-hydroxy-2-nonenal-modified Ro60 or unmodified Ro60. Methods used included ELISA, including an inside-out RBC membrane ELISA, and Crithidia lucilae assays.

RESULTS:

Commercial anti-spectrin sera bound significantly to Ro60 (OD 2.6 ± 0.1), Ro60 multiple antigenic peptides (MAPs) (3 out of 21 Ro60 MAPs), La (OD 4.4±0.5), and La fragments as well as to double stranded DNA but not to BSA (OD 0.6±0.1). Anti-spectrin binding to purified spectrin could be inhibited by spectrin (>95%), and Ro60 or La (70%). When the binding of anti-spectrin was tested against a nested set of La fragments we found that a N4 fragment representing the C-terminal 250 aa (aa 159 to 408) bound the strongest (OD=4.12) followed by a N9 fragment (the C-terminal 36aa; aa373 to 408 (OD=1.36). Also, significant anti-spectrin antibody levels were induced by Ro60 and HNE-modified Ro60 immunisation.

CONCLUSIONS:

We found intermolecular epitope spreading from Ro60/La to spectrin and vice versa, and this may have pathological significance in these animal models of autoimmunity.

• Authors: Biji T Kurien, Yaser Dorri, Michael Bachmann, R Hal Scofield
• Journal: Clinical and experimental rheumatology (Clin Exp Rheumatol) 2012 Nov-Dec Vol. 30 Issue 6 Pg. 886-93 ISSN: 0392-856X [Print] Italy
• PMID: 22776429 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)

Chemical References

• Aldehydes
• Antibodies, Antinuclear
• Autoantigens
• Epitopes
• Ribonucleoproteins
• SS-A antibodies
• SS-A antigen
• SS-B antibodies
• SS-B antigen
• Spectrin
• DNA
• 4-hydroxy-2-nonenal

Topics

• Aldehydes (administration & dosage, immunology)
• Animals
• Antibodies, Antinuclear (blood)
• Autoantigens (immunology)
• Autoimmunity
• Binding, Competitive
• DNA (metabolism)
• Enzyme-Linked Immunosorbent Assay
• Epitope Mapping
• Epitopes
• Immunization
• Protein Binding
• Rabbits
• Ribonucleoproteins (administration & dosage, immunology)
• Spectrin (administration & dosage, immunology)