NUCLEOSOME ANTIGEN
AROTEC_Nucleosome_Product_Info.pdf Version/Date: A/00.08.18
ATN02-02 Nucleosome antigen 0.20 mg
ATN02-05 Nucleosome antigen 0.50 mg
ATN02-10 1.0 mg
_________________________________________________________________________________
Description of the Product
Purified from bovine thymus. After coating onto ELISA plates
the product will bind autoantibodies to nucleosome antigen.
Purity: The nucleosome antigen is more than 90% pure, as
assessed by SDS gel electrophoresis.
Concentration: 0.5 -2.0 mg protein/ml.
Storage: The product is stabilised with 0.1% Micr-O-protectTM
.
Store at -20 o
C or below （long term） or at +4o
C （short term）.
Avoid repeated freezing and thawing. Mix thoroughly before
use.
Clinical and Biochemical Data
Anti-nucleosome antibodies （also referred to as anti-chromatin
antibodies） constitute one of the first autoantibody specificities
found to be present in systemic lupus erythematosus （SLE）
having been detected as early as 1948 using the LE cell
test1,2. The prevalence of anti-nucleosome antibodies in SLE is
of the order of 50-100%2
, and the nucleosome has been
identified as the initiating and driving immunogen in SLE3,4
.
Antinucleosome antibodies are now considered to be a more
sensitive marker for SLE than anti-dsDNA antibodies5
and a
high anti-nucleosome antibody titre has been reported to be
indicative of lupus nephritis6-8. Anti-nucleosome antibodies
have been found （with a lower prevalence than in SLE） in a
number of other autoimmune diseases6,9,10,19 such as systemic
sclerosis, Sjogren's syndrome and mixed connective tissue
disease and are also found in 40-50% of patients with
autoimmune hepatitis type I11,12. Anti-ribosomal P antibodies
have also been reported to bind to nucleosomes13,14
.
The nucleosome is the basic structural subunit of chromatin,
the native complex of histones and DNA found in the nucleus
of eukaryotic cells. It is composed of about 200 base pairs of
DNA wrapped twice around a （H2A-H2B-H3-H4）2 histone
octamer with histone H1 bound on the periphery2,15,16,19
.
Nucleosomes can be isolated by digesting the linker DNA
holding them together in chromatin with micrococcal nuclease.
The most effective form of nucleosomes for detecting patient
autoantibodies are prepared in this way and stripped of H1
histone to yield a nucleosome core particle in which 146 base
pairs of DNA are wrapped around an octamer of two H2A-H2B
dimers that surround an H3-H4 tetramer2,17. Autoantibodies
against subnucleosome particles occur in SLE, they are
however less frequent3
.
AROTEC nucleosome antigen is prepared from calf thymus
chromatin and contains the four core histones H2A, H2B, H3
and H4 bound to DNA of about 146 base pairs in length.
Histone amino acid sequences are highly conserved between
species, even between animals and plants18. Homology
between human and bovine amino acid sequences is as
follows （ExPASy accession numbers human:bovine are
shown）:
H2A （P0C0S5:P0C0S4） 128 aa: 128 identical
H2B （B2R4S9:A5D7N2） 126 aa: 125 identical, 1 conservative
subsitition
H3 （P84243:Q5E9F8） 136 aa: 136 identical
H4 （P62805:P62803） 103 aa: 103 identical
Methodology
The following is an ELISA procedure which can be used to
detect anti-nucleosome autoantibodies in human serum using
the ATN02 purified nucleosome antigen:
1. Dilute the purified antigen to 1.0-2.0 g/ml in 20 mM
Tris/HCl buffer, pH 8.0; containing 0.15 M NaCl.
2. Coat ELISA plates with 100 l of diluted antigen per well.
Cover and incubate 24 hours at +4o
C.
3. Empty the plates and remove excess liquid by tapping on a
paper towel.
4. Block excess protein binding sites by adding 200 l PBS
containing 1% BSA per well. Cover and incubate at +4o
C
overnight.
5. Empty plates and apply 100 l of serum samples diluted
1:100 in PBS / 1% BSA / 0.1% Tween
20. Incubate at room
temperature for 1 hour.
6. Empty plates and add 200 l PBS / 0.1% Tween
20 per
well. Incubate 5 minutes then empty plates. Repeat this step
twice.
7. Apply 100 l anti-human IgG-enzyme conjugate
（horseradish peroxidase or alkaline phosphatase） diluted in
PBS / 1% BSA / 0.1% Tween
20 per well and incubate for 1
hour.
8. Repeat step 6.
9. Add enzyme substrate and stop the reaction when
appropriate.
10. Read absorbance in an ELISA spectrophotometer.
References
1. Hargraves, M.M. et al. （1948） Proc. Mayo Clin. 23, 25
2. Gomez-Puerta, J.A. et al. （2008） Autoimmunity Rev. 7, 606
3. Burlingame, R.W. et al. （1994） J. Clin. Invest. 94, 184
4. Muller, S. et al. （2008） Lupus 17, 431
5. Putova, I et al. （2007） Annals N.Y. Acad. Sci. 1109, 275
6. Cervera, R. et al. （2003） Ann. Rheum. Dis. 62, 431
7. Manson, J.J. （2009） Arthritis Res. Ther. 11, R154
8. Kiss, E. et al. （2009） Autoimmunity 42, 393
9. Amoura, Z. et al. （2000） Arthritis Rheum. 43, 76
10. Schett, G. et al. （2002） Lupus 11, 704
11. Ghillani-Dalbin, P. et al. （2003） Lupus 12, 833
12. Koutouzov, S. et al. （2004） Rheum. Dis. Clin. North Am. 30, 529
13. Chindalore, V. et al. （1998） Clin. Immunol. Immunopathol. 87, 292
14. Caponi, L. et al. （2002） Clin. Exp. Immunol. 130, 541
15. Lutter, L.C. （1978） J. Mol. Biol. 124, 391
16. Luger, K. et al. （1997） Nature 389, 251
17. Burlingame, R.W. & Rubin, R.L. （1990） J. Immunol. Meth. 134, 187
18. Baxevanis, A.D. & Landsman, D. （1996） Nucleic Acid Res. 24, 245
19. Decker, P. （2006） Clin. Chim. Acta 366, 48
Micr-O-protect is from Roche Diagnostics GmbH （Mannheim,
Germany）.
Tween
20 is a registered trademark of ICI Americas Inc.
NOTE: No patented technology has been used by AROTEC
during the preparation of this product.
