Humoral immune response characterization of the type V collagen induced scleroderma experimental model / Caracterização da resposta imune em modelo experimental de esclerodermia induzida por colágeno tipo V

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

Experimental models for human diseases are of utmost importance, since they allow the study of their pathogenesis and therapeutic approach. In this group we can include the experimental model of collagen V-induced scleroderma, in rabbits, with histological alterations (skin, lung and kidney) similar to those observed in humans. Auto-immune diseases have an unknown etiology, and are characterized by the presence of auto-antibodies in serum. In this aspect, 90%-95% of the patients with scleroderma present some kind of auto-antibody against intracellular antigens (RNA polymerase I, II and III nucleoproteins, Scl-70, centriolar or golgins) or to components of the extracellular matrix (collagen). This study aims to assess the immune response of the animal subjects in a scleroderma experimental model. The animals sera were tested for auto-antibodies and other serum immunological factors that would point to an active immunological process, parallel to the developing tissue lesions, including anti-collagen V, III and I antibodies, circulating immune complexes, rheumatoid factor, complement levels, antinuclear antibodies (ANA) by indirect immunofluorescence in HEp-2 (IFI) cells, and characterization of target antigens with an immunoblot. The analysis of the immune response in the studied animals revealed that histological alterations in lungs, kidneys and skin developed with an increase of the serum levels of anti-collagen V antibodies. Furthermore, all the Col Vimmunized animals presented antibodies against other types of collagen as well. These animals also developed a strong immune response against intracellular antigens, being 100% positive for ANA, showing also immune complexes in sera obtained 30, 75 and 120 days after immunization with Col V, when compared to the control groups (albumin and Freunds complete adjuvant). All the animals from the Col V group showed a cytoplasmic pattern at the IFI, Golgi simile and, in 10% of the cases, additional reactivity to the centrioles. Both auto-antibodies are rare, yet were already described in patients with scleroderma. The pre-absorption of these animals sera with Col V did not interfere with the ANA reactivity. The characterization of the target antigens showed a uniform reactivity to high molecular weight proteins of human epithelial cells (>or = 175 kDa), which progressed with the immunization time. Acid eluats containing antibodies against the 175 kDa fraction reproduced the same IFI reactivity pattern of the original serum. The results demonstrate that immunization of rabbits with human Col V results in an exuberant immune response, characterized by the presence of autoantibodies against intracellular components.

ASSUNTO(S)

colágeno/efeitos adversos collagen/adverse effects escleroderma difusa/induzido quimicamente disease models animal coelhos antibody formation/immunology modelos animais de doenças rabbits esquema de imunização formação de anticorpos/ imunologia scleroderma diffuse/chemically induced immunization schedule

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