DOI Seite / Zitierlink:
https://doi.org/10.11588/diglit.48120#0072
54 Molecular and Cell Biology of Autoantibodies and Autoimmunity
Autoantibodies to a Histone Cross-Reactive DNA-Binding Protein of
Mr 110000 in Systemic Lupus Erythematosus and Other Diseases and
in Autoimmune Mice
S. Minota, W. N. Jarjour, R.A. S. Roubey, T. Mimura, and J. B. Winfield
Division of Rheumatology and Immunology, University of North Carolina at Chapel Hill,
Chapel Hill, NC 27514, USA
This investigation characterizes a novel 110 kD autoantigen (110 K) recogniz-
ed by autoantibodies in serum from patients with systemic lupus erythematosus
(SLE) or certain other autoimmune or viral diseases, and MRL/Mp-lpr/lpr mice.
IgM and, less frequently, IgG autoantibodies to this protein were detected by one-
and two-dimensional immunoblotting and by immunoprecipitation utilizing non-
ionic detergent lysates of various human lymphoid and non-lymphoid cells. By
immunoblotting, 110 K was shown to be an intracellular DNA-binding protein of
pl 5.4, containing at least one phosphotyrosyl residue. In cell fractionation ex-
periments, 110K was present in both the nucleus and the cytosol, but not in
plasma membranes or mitochondria. PHA stimulation appeared to increase the
amount of 110K in peripheral T lymphocytes, suggesting that cellular activation
either increased the expression of the antigen or altered its structure such that an-
tibody reactivity was enhanced. Certain SLE sera with pre-formed DNA/an-
ti-DNA complexes also reacted with 110 K in immunoblots via DNA-110 K bind-
ing. Autoantibodies to 110 K were distinguished from DNA/anti-DNA complexes
by retention of HOK-binding activity in sera subjected to DNase I digestion and
in IgM purified by sucrose density gradient ultracentrifugation under immune
complex disassociating conditions. IgM anti-110 K antibodies in SLE sera were
associated in all but two instances with antibodies to histone H 1. Linkage of an-
ti-110 K with antibodies to histone H2B was demonstrated as well. Affinity
purification of anti-110 K and anti-histone antibodies revealed that this relation-
ship was due, in part, to antibody cross-reactivity. Considerable evidence was ob-
tained to suggest that 110 K was distinct from hsp 110, a stress protein, and from
already-defined autoantigens of approximately the same size, i.e., topoisomerase
I, PM-Scl, and RNA polymerase I.
IgM autoantibodies to 110K were particularly prevalent in childhood SLE
(15/15, 100%), acute hepatitis A infection (16/20, 80%), Sjogren's syndrome
(17/24, 71%), adult SLE (27/42, 67%), and systemic sclerosis (7/16, 44%). An-
ti-HOK was detected less frequently in patients with infectious mononucleosis
(4/20, 20%) or other rheumatic diseases: polymyositis (2/10, 20%), rheumatoid
arthritis (1/20, 5%), polymyalgia rheumatica (1/20, 5%), and spondyloar-
thropathy (0/20). Anti-110 K antibodies were not demonstrable in serum from 10
normal individuals. In conclusion, the data suggest a special association of auto-
Autoantibodies to a Histone Cross-Reactive DNA-Binding Protein of
Mr 110000 in Systemic Lupus Erythematosus and Other Diseases and
in Autoimmune Mice
S. Minota, W. N. Jarjour, R.A. S. Roubey, T. Mimura, and J. B. Winfield
Division of Rheumatology and Immunology, University of North Carolina at Chapel Hill,
Chapel Hill, NC 27514, USA
This investigation characterizes a novel 110 kD autoantigen (110 K) recogniz-
ed by autoantibodies in serum from patients with systemic lupus erythematosus
(SLE) or certain other autoimmune or viral diseases, and MRL/Mp-lpr/lpr mice.
IgM and, less frequently, IgG autoantibodies to this protein were detected by one-
and two-dimensional immunoblotting and by immunoprecipitation utilizing non-
ionic detergent lysates of various human lymphoid and non-lymphoid cells. By
immunoblotting, 110 K was shown to be an intracellular DNA-binding protein of
pl 5.4, containing at least one phosphotyrosyl residue. In cell fractionation ex-
periments, 110K was present in both the nucleus and the cytosol, but not in
plasma membranes or mitochondria. PHA stimulation appeared to increase the
amount of 110K in peripheral T lymphocytes, suggesting that cellular activation
either increased the expression of the antigen or altered its structure such that an-
tibody reactivity was enhanced. Certain SLE sera with pre-formed DNA/an-
ti-DNA complexes also reacted with 110 K in immunoblots via DNA-110 K bind-
ing. Autoantibodies to 110 K were distinguished from DNA/anti-DNA complexes
by retention of HOK-binding activity in sera subjected to DNase I digestion and
in IgM purified by sucrose density gradient ultracentrifugation under immune
complex disassociating conditions. IgM anti-110 K antibodies in SLE sera were
associated in all but two instances with antibodies to histone H 1. Linkage of an-
ti-110 K with antibodies to histone H2B was demonstrated as well. Affinity
purification of anti-110 K and anti-histone antibodies revealed that this relation-
ship was due, in part, to antibody cross-reactivity. Considerable evidence was ob-
tained to suggest that 110 K was distinct from hsp 110, a stress protein, and from
already-defined autoantigens of approximately the same size, i.e., topoisomerase
I, PM-Scl, and RNA polymerase I.
IgM autoantibodies to 110K were particularly prevalent in childhood SLE
(15/15, 100%), acute hepatitis A infection (16/20, 80%), Sjogren's syndrome
(17/24, 71%), adult SLE (27/42, 67%), and systemic sclerosis (7/16, 44%). An-
ti-HOK was detected less frequently in patients with infectious mononucleosis
(4/20, 20%) or other rheumatic diseases: polymyositis (2/10, 20%), rheumatoid
arthritis (1/20, 5%), polymyalgia rheumatica (1/20, 5%), and spondyloar-
thropathy (0/20). Anti-110 K antibodies were not demonstrable in serum from 10
normal individuals. In conclusion, the data suggest a special association of auto-