Autoantibody profile in the experimental model of scleroderma induced by type V human collagen.
The aim of this study is to evaluate the humoral autoimmune response in the experimental model of systemic sclerosis (SSc) induced by human type V collagen (huCol V). New Zealand rabbits were immunized with huCol V in Freund's complete adjuvant (FCA) and boosted twice with 15 days intervals with huCol V in Freund's incomplete adjuvant. Control groups included animals injected only with FCA or bovine serum albumin. Bleeding was done at days 0, 30, 75 and 120. Tissue specimens were obtained for histopathological investigation. Serological analysis included detection of antibodies against huCol V and anti-topoisomerase I (Anti-Scl70) by enzyme-linked immunosorbent assay, antinuclear antibodies (ANA) by indirect immunofluorescence, and rheumatoid factor (RF) by a latex agglutination test. Target antigens were characterized by immunoblot. Histological analysis revealed extracellular matrix remodeling with fibrosis and vasculitis. Anti-Scl70 and ANA were detected as early as 30 days in all huCol V animals. The universal ANA staining pattern was Golgi-like. This serum reactivity was not abolished by previous absorption with huCol V. Characterization of the target antigen by immunoblot revealed two major protein fractions of 175,000 and 220,000 MW. Similarly to ANA, there was a gradual increase of reactivity throughout the immunization and also it was not abolished by preincubation of serum samples with huCol V. RF testing was negative in hyperimmune sera.


CONCLUSIONS
The production of autoantibodies, including anti-Scl70, a serological marker for SSc associated with histopathological alterations, validates huCol V induced-experimental model and brings out its potential for understanding the pathophysiology of SSc.
Callado
Maria R M
MR
Department of Rheumatology, Fortaleza General Hospital, Ceará, Brazil. callado@baydenet.com.br
Viana
Vilma S T
VS
Vendramini
Margarete B G
MB
Leon
Elaine P
EP
Bueno
Cleonice
C
Velosa
Ana P P
AP
Teodoro
Walcy R
WR
Yoshinari
Natalino H
NH
D000818:Animals; D000974:Antibodies, Antinuclear / Q000097:blood; D001323:Autoantibodies / Q000096:biosynthesis*; D015415:Biomarkers / Q000097:blood; D024062:Collagen Type V / Q000276:immunology*; D004264:DNA Topoisomerases, Type I / Q000276:immunology; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D004947:Esophagus / Q000473:pathology; D005260:Female; D006801:Humans; D007114:Immunization / Q000379:methods; D008168:Lung / Q000473:pathology; D011817:Rabbits; D012217:Rheumatoid Factor / Q000097:blood; D012595:Scleroderma, Systemic / Q000276:immunology* / Q000473:pathology; D012867:Skin / Q000473:pathology
D000974:Antibodies, Antinuclear; D001323:Autoantibodies; D015415:Biomarkers; D024062:Collagen Type V; D012217:Rheumatoid Factor; D004264:DNA Topoisomerases, Type I