Showing papers by "Eng M. Tan published in 1986"

Immunolocalization and partial characterization of a nucleolar autoantigen (PM-Scl) associated with polymyositis/scleroderma overlap syndromes.

Abstract: Precipitating anti-PM-Scl antibodies are present in sera from patients with polymyositis, scleroderma, and polymyositis/scleroderma overlap syndromes. By indirect immunofluorescence microscopy, anti-PM-Scl antibodies stained the nucleolus in cells of different tissues and species, suggesting that the antigen is highly conserved. By electron microscopy, anti-PM-Scl antibodies reacted primarily with the granular component of the nucleolus. Drugs that inhibit rRNA synthesis had a marked effect on the expression of PM-Scl antigen. In actinomycin D-treated cells, immunofluorescence staining by anti-PM-Scl was significantly reduced with residual staining restricted to the granular regions of nucleoli. Treatment with 5,6-dichloro-beta-D-ribofuranosylbenzimidazole (DRB) also selectively reduced nucleolar staining. On a molecular level, anti-PM-Scl antibodies precipitated 11 polypeptides with molecular weights (Mr) ranging from 110,000 to 20,000. The Mr 80,000 and 20,000 polypeptides were phosphorylated. Evidence suggests that the PM-Scl antigen complex may be related to a preribosomal particle.

Procainamide elicits a selective autoantibody immune response.

Abstract: The specificity of the in vivo humoral immune response elicited by procainamide was examined by solid-phase assays, immunofluorescence, immunoprecipitation and a cytotoxicity assay. Serial samples obtained from patients during their procainamide therapy showed a progressive increase in antibodies to histones and denatured DNA, and both activities decreased after discontinuation of therapy. In contrast antibodies to tetanus, human IgG (rheumatoid factor) and heterologous lymphocytes were unaffected by procainamide treatment, indicating that they were not drug-induced. Of 29 sera examined by protein-A-facilitated immunoprecipitation, four sera had antibody to ribosomal RNA and three sera immunoprecipitated a 40kD protein. Antinuclear antibodies were invariably present but absorption studies showed that these activities were due to anti-histone antibodies. These results indicate that procainamide-induced autoimmunity is characterized predominantly by an anti-histone and anti-denatured DNA immune response.