Normolipemic plane xanthoma associated with adenocarcinoma and severe itch.

Normolipemic plane xanthomas are yellow-red-colored flat patches or plaques with barely palpable borders, under normolipemic conditions usually involving the eyelids, the lateral sides of the neck, the upper aspect of the trunk, or the flexural folds. Histologically the lesions are characterized by an infiltrate consisting of foamy macrophages in the papillary and middermis with a distinct perivascular localization. Plane xanthoma has been associated with monoclonal gammopathy, cryoglobulinemia, and myeloproliferative disorders.

Significance of the immune response to a major, conformational B-cell epitope on the hepatitis C virus NS3 region defined by a human monoclonal antibody.

The nonstructural protein NS3 of hepatitis C virus (HCV) possesses two enzymatic domains which are thought to be essential for the virus life cycle: an N-terminal serine-type proteinase, responsible for the processing of nonstructural polypeptides, and a C-terminal nucleoside triphosphatase/helicase, presumably involved in the unwinding of the viral genome. The human antibody response to NS3 usually appears early in the course of HCV infection and is predominantly directed against the carboxyl-terminal portion; however, its fine specificity and clinical significance are largely unknown. We have generated a human monoclonal antibody (hMAb), designated CM3.

Detection of hepatitis C virus antigen by immuno-histochemical staining: a histological marker of hepatitis C virus infection.

Hepatitis C virus has been recognized as a major cause of non-A, non-B viral hepatitis. Although serologic tests have been commercialized, no specific histological or immuno-histochemical markers for hepatitis C virus infection are available for routine use. In an effort to detect hepatitis C virus antigen in liver tissue we investigated the immuno-reactivity to monoclonal antibodies on frozen liver tissue from a chimpanzee and patients with chronic non A, non B hepatitis.

A human monoclonal antibody specific for the N terminus of the hepatitis C virus nucleocapsid protein.

PBMC from a patient with chronic hepatitis C virus (HCV) infection were immortalized with EBV and plated by limiting dilution. Cultures secreting antibodies reactive in a commercial HCV II generation ELISA, which incorporates Ag derived from the nucleocapsid, NS3, and NS4 regions, were repeatedly cloned in the presence of feeder cells and growth factors. Of 23 initially immunoreactive cultures, only one cloned line, designated B12.

Independent deposition of heterogeneous nuclear ribonucleoproteins and small nuclear ribonucleoprotein particles at sites of transcription.

The major nuclear ribonucleoproteins (RNPs) involved in pre-mRNA processing are classified in broad terms either as small nuclear RNPs (snRNPs), which are major participants in the splicing reaction, or heterogeneous nuclear RNPs (hnRNPs), which traditionally have been thought to function in general pre-mRNA packaging. We obtained antibodies that recognize these two classes of RNP in Drosophila melanogaster. Using a sequential immunostaining technique to compare directly the distribution of these RNPs on Drosophila polytene chromosomes, we found that the two patterns were very similar qualitatively but not quantitatively, arguing for the independent deposition of the two RNP types and supporting a role for hnRNP proteins, but not snRNPs, in general transcript packaging.

Analysis of an immunodominant epitope of topoisomerase I in patients with systemic sclerosis.

In this paper an immunodominant epitope of Topoisomerase I is described. An epitope expression sublibrary was constructed from Topoisomerase I cDNA. The subclones were screened with an antiserum from a patient with systemic sclerosis (SSc).

Zinc finger-like structure in U1-specific protein C is essential for specific binding to U1 snRNP.

The U1 small nuclear ribonucleoprotein (snRNP) contains three specific proteins denoted 70K, A and C, in addition to the common proteins. Specific functions of these proteins are not known although recently protein C was shown to be involved in the binding of U1 snRNP to the 5' splice site of a pre-mRNA. Unlike proteins A and 70K, U1-C lacks an RNA binding domain (RNP-80 motif) and does not appear to bind directly to U1 snRNA.

Analysis of U1snRNP-specific A protein cross-linked complexes.

The organization of the U1snRNP-specific A protein (34 kDa) has been analyzed by 12 and 16 A thiol-reversible chemical cross-linking and Western blotting. A-containing cross-linked complexes had molecular masses of 43, 47, 56, 62, 67, 105 and 125 kDa. None of these complexes could be cross-linked following ribonuclease digestion, suggesting that UsnRNA may play important roles in the spatial organization of A and other proteins.

Use of recombinant RNP peptides 70K and A in an ELISA for measurement of antibodies in mixed connective tissue disease: a longitudinal follow up of 18 patients.

In a three year prospective study disease activity variables and levels of antibody against the RNP-peptides 70K and A were measured in 18 patients with mixed connective tissue disease. Antibody measurement entailed use of cloned autoantigens in an enzyme linked immunosorbent assay (ELISA). Fluctuations in antibody levels against 70K and A were most commonly noted in patients who also had changes in disease activity, but these changes in serology and disease activity were synchronous in only a minority of the episodes.

Epitope patterns of anti-RNP antibodies in rheumatic diseases. Evidence for an antigen-driven autoimmune response.

Autoantibodies against small nuclear ribonucleoproteins (snRNP) are common in systemic lupus erythematosus and related disorders. The 3 categories, anti-(U1)RNP, anti-(U1, U2)RNP, and anti-Sm, all contain a common antibody specificity directed against the U1 snRNP-associated A protein. To determine the specificity of anti-U1 snRNP A protein antibodies for various antigenic sites, we tested 26 different anti-snRNP-positive sera for reactivity with fragments of the U1 snRNP A protein, which was produced using recombinant DNA technology.

A recombinant topoisomerase I used for autoantibody detection in sera from patients with systemic sclerosis.

We report the expression of a cDNA clone encoding 695 carboxyl-terminal amino acids of human DNA topoisomerase I (topoI) in Escherichia coli. More than 96% of the anti-HeLa topoI-positive sera from patients with a connective tissue disease displayed also an immunoreactivity with this recombinant protein (the HTopoA protein). Sera from patients with a definite diagnosis systemic sclerosis and reacting with HeLa topoI, all reacted with the HTopoA protein as well.

Autoantibody production against the U small nuclear ribonucleoprotein particle proteins E, F and G in patients with connective tissue diseases.

The nucleoplasmic U small nuclear ribonucleoprotein particles (snRNP) have a set of seven proteins in common which are designated B', B, D, D', E, F and G. Patients suffering from rheumatoid autoimmune diseases such as systemic lupus erythematosus often develop autoantibodies against the proteins B', B, and D. Here we describe a sensitive immunoassay which allows the specific detection of autoantibodies reacting with the E, F or G snRNP proteins.

Mapping of B cell epitopes on small nuclear ribonucleoproteins that react with human autoantibodies as well as with experimentally-induced mouse monoclonal antibodies.

Small nuclear ribonucleoprotein (snRNP) particles are a class of RNA-containing particles in the nucleus of eukaryotic cells. They consist of uridylate-rich small nuclear RNA complexed with several proteins. snRNP particles U1, U2, U4/U6, and U5 all contain a common protein core consisting of proteins B'/B, D, D', E, F, and G.

U1 small nuclear ribonucleoprotein particle-specific proteins interact with the first and second stem-loops of U1 RNA, with the A protein binding directly to the RNA independently of the 70K and Sm proteins.

The U1 small nuclear ribonucleoprotein particle (U1 snRNP), a cofactor in pre-mRNA splicing, contains three proteins, termed 70K, A, and C, that are not present in the other spliceosome-associated snRNPs. We studied the binding of the A and C proteins to U1 RNA, using a U1 snRNP reconstitution system and an antibody-induced nuclease protection technique. Antibodies that reacted with the A and C proteins induced nuclease protection of the first two stem-loops of U1 RNA in reconstituted U1 snRNP.

Marker antibodies in scleroderma and polymyositis: clinical associations.

Sera of 34 patients with progressive systemic sclerosis and of 11 patients with polymyositis/dermatomyositis (PM/DM) were analyzed by the immunoblotting technique for the presence of marker antibodies. The presence of anti-centromere, anti-Topoisomerase-I (anti-Topo-I) and anti-Jo-1 antibodies was found to be highly specific for the CREST syndrome, diffuse scleroderma and PM/DM, respectively, but only of limited sensitivity (78, 44 and 45%, respectively). Anti-Topo-I positive diffuse scleroderma patients had a more severe disease (digital pitting scars and renal insufficiency) than anti-Topo-I negative diffuse scleroderma patients.

Small nuclear RNA-associated proteins are immunologically related as revealed by mapping of autoimmune reactive B-cell epitopes.

Autoantibodies from a patient with systemic lupus erythematosus, which recognize U1 and U2 small nuclear ribonucleoprotein particles (snRNPs), were used to map B-cell autoepitopes on the U1 snRNP-specific A protein. This protein contains two regions that are highly similar to regions in the U2 snRNP-specific B" protein. A site termed epitope 2 maps in one such region and was found to react with antibodies cross-reactive between A and B".

Anti-56K: a novel, frequently occurring autoantibody specificity in connective tissue disease.

A novel frequently occurring autoantibody specificity in serum from connective tissue disease patients is described. The autoantibodies as detected by immunoblotting are directed against a 56,000 Dalton (56K) antigen, that after biochemical fractionation predominantly is found in the cytoplasmic fraction of various cell types and tissues. Attempts to localize the antigen more precisely were unsuccessful primarily because these antibodies do not produce a positive immunofluorescence pattern.

Detection of autoantibodies in a quantitative immunoassay using recombinant ribonucleoprotein antigens.

A human cDNA expression library was screened with anti-ribonucleoprotein (RNP) antibodies from patients with connective tissue diseases. Three cDNA clones were isolated encoding 70 kD, A and B" ribonucleoprotein autoantigens which were expressed as beta-galactosidase fusion proteins. Antigens were purified and used to develop sensitive ELISAs suitable for the routine screening of large series of sera from patients with connective tissue diseases.

Molecular cloning of the cDNA for the human U2 snRNA-specific A' protein.

The A' polypeptide is one of the protein constituents of the U2 snRNP particle. A potentially full-length cDNA clone containing the complete coding sequence for this U2 snRNP-specific protein was isolated by screening of a human lambda gt11 expression vector library with an autoimmune anti-(U1,U2)RNP serum. Monospecific antibodies, eluted from the 140-150 kD fusion protein of this cDNA recombinant, specifically recognized the A' protein on immunoblots and immunoprecipitated U2 snRNP particles from nuclear extracts.

Human U1 snRNP-specific C protein: complete cDNA and protein sequence and identification of a multigene family in mammals.

A complementary DNA clone for the human U1 snRNP-specific C protein has been isolated. The nucleotide sequence of the 733 bp cDNA insert includes a 15 bp 5'-untranslated region, an open reading frame of 477 bp corresponding to 159 amino acids (Mr = 17,373 D), and a 223 bp 3'-untranslated region. The identity of the clone was confirmed by in vitro translation of hybrid-selected mRNA or an RNA transcript synthesized from the cDNA.

The use of immunoblotting to detect antibodies to nuclear and cytoplasmic antigens. Clinical and serological associations in rheumatic diseases.

Using the immunoblotting technique, sera from 433 patients with rheumatic diseases were screened for the presence of antibodies against several nuclear and cytoplasmic antigens, such as RNP, Sm, Ro(SSA), La(SSB), CR-19 (centromeric antigen), Topo-1 (Scl-70), Jo-1, histone and 56 kD. At the same time clinical data from these patients were collected without prior knowledge of the immunoblotting results. Syndrome-specific autoantibodies were found for mixed connective tissue disease (antibodies against the RNP related 70 kD antigen), for CREST (anti-CR-19 antibodies), for diffuse scleroderma (anti-Topo-1 antibodies) and for polymyositis (anti-Jo-1 antibodies).

cDNA cloning of the human U1 snRNA-associated A protein: extensive homology between U1 and U2 snRNP-specific proteins.

Sera from patients with connective tissue diseases often contain antibodies against snRNA-associated proteins. Using one of these sera in an immunological screening of a human lambda gt11 expression vector cDNA library, two cDNA clones for the U1 snRNP-specific A protein, termed lambda HA-1 and lambda HA-2, were isolated. Monospecific antibodies, eluted from the beta-galactosidase fusion protein of either clone reacted with the U1 snRNP-specific A antigen.