Antibodies In Sera Of Patients Research Articles

Parvovirus B19 antibodies in sera of patients with unexplained exanthemata from Belém, Pará, Brazil.

Parvovirus B19 antibodies in sera of patients with unexplained exanthemata from Belém, Pará, Brazil.

Immunodetection of TSH receptor antibodies in sera of patients with autoimmune thyroid disease by ELISA (enzyme-linked immunosorbent assay)

An ELISA system has been developed for detecting antibodies to TSH receptor peptides. It has been used to study antibodies against peptides corresponding to four different extracellular domains of human TSH receptor in the sera of patients with Graves' disease (N = 10, TBII positive) and Hashimoto's disease (N = 10, TBII negative). Two peptides, N (amino acid residues nos. 29-57) and P3 (nos. 359-371) are specific for TSH receptor, and two, C (nos 172-202) and P1 (nos. 398-417) are homologous with the corresponding portions of the LH/CG receptor. All of the peptides were recognized by sera from patients with Graves' disease but individual sera recognized different numbers and combinations of these peptides. Sera from patients with Hashimoto's disease did not bind to any of these peptides. These results suggest that antibodies to the TSH receptor in patients with Graves' disease recognize various regions of extracellular domain of TSH receptor in addition to TSH receptor-specific regions.

Analysis of antineuronal antibodies in sera of patients with amyotrophic lateral sclerosis

Our investigation consisted in 10-days treatment of vaginal mucous membrane wounds in white not inbred rats by introduction of natural cytokines complex into the vagina. At the same time the dynamics of vaginal phagocytes oxygen-depended function change was studied. We have ascertained the activating influence of the cytokines complex on the phagocytes chemiluminescence (CL) that found expression in 2.5-7 times fold augmentation of the CL intensity in comparison with control level (an equal portion of Medium--199 was introduced in the vagina of control-group rats). Having ended the application of the cytokines complex we have observed a rather fast normalization of the cells' activity (by the 15-17 days), consequently the cytokines did not have a distant effect on the oxygen-depended phagocytes function. We consider the activation of the phagocytes in wound as well as the bactericidal effect of the oxygen free radicals generated by the phagocytes as positive result.

Borna disease virus: nature of the etiologic agent and significance of infection in man.

This review presents data on the characterization of Borna disease virus (BDV) and its potential as a possible causative agent in humans. The isolation of: (i) BDV-specific cDNA clones that encode various BDV-specific proteins and (ii) partially purified virus particles led to the conclusion that the viral genome consists of negative-sense, single-stranded RNA. The organization of the BDV-specific RNA species appears to be a nested set of overlapping subgenomic RNA transcripts. Furthermore, evidence is presented that BDV can infect humans and may cause certain psychiatric and neurological disorders. This concept is supported by: (i) the finding of virus-specific antibodies in sera of patients with neuropsychiatric diseases and (ii) results obtained during attempts to isolate BDV or a BDV-related agent from the cerebrospinal fluid of seropositive patients.

Serologic response to the Borrelia burgdorferi flagellin demonstrates an epitope common to a neuroblastoma cell line.

Antibodies in sera of 7 patients with neurologic manifestations of Lyme borreliosis and a monoclonal antibody (mAb H9724) to the flagellin of Borrelia burgdorferi have been shown to bind neural tissue. To identify the antibody binding site common to the B. burgdorferi flagellin and the neural tissue, we made recombinant fusion proteins expressing epitopes of flagellin. Antibodies in patients' sera and mAb H9724 bound within an 18-amino acid epitope (residues 208-225) in the central region of flagellin, whereas two other mAbs bound to epitopes mapping elsewhere in the protein. Antibodies in patients sera and mAb H9724 also bound to a human neuroblastoma cell line. Absorption of patients sera with a peptide, EGVQQEGAQQPA, corresponding to amino acids 213-224 of flagellin, inhibited binding to the neuroblastoma cell line. The data suggest that the immune response to a specific B-cell epitope within flagellin, shared by a human neuroblastoma cell line, may be involved in the pathogenesis of neuroborreliosis.

Human African Trypanosomiasis: Presence of Antibodies to Galactocerebrosides

Improvements were made in the immunodetection of anti-galactocerebroside (anti-GalC) antibody in sera of patients with human African trypanosomiasis by thin-layer chromatography, enzyme-linked immunosorbent assay, and immunoadsorption. Rabbit anti-GalC antibodies were used to standardize these techniques and demonstrate their specificity. Anti-GalC antibodies were found in the sera of 42.8% of 63 patients with human African trypanosomiasis. Thirty-four control subjects living in the same endemic area were also tested. Anti-GalC levels were higher in human African trypanosomiasis patients with neurologic disturbances compared with patients without such disturbances. These antibodies were distributed mainly between the IgG and IgM classes, but 28% of the patients with human African trypanosomiasis had increased IgA levels without anti-GalC antibody activity.

Antibodies to cathepsin G in Crohn's disease.

Antibodies directed against antigens in human neutrophils have proved to be of great diagnostic value in certain systemic vasculitides. Recent reports have focused the attention on these antigens as targets of antibodies in sera of patients with inflammatory bowel disease. We investigated the sera drawn from 60 patients suffering from biopsy proven Crohn's disease and 15 patients with active ulcerative colitis. Using sensitive enzyme-linked immunosorbent assays with purified antigens and Western blotting the following antibodies could be demonstrated: cathepsin G (cat-G) antibodies IgG 38.3%, IgM 13.3%, IgA 23.3% and antibodies against human leucocyte elastase (HLE) IgG, IgA, IgM 3.3%. Low but significant correlations could be found for cat-G antibodies (IgG) and the van HEES index of activity. 73.9% of the cat-G (IgG) positive patients had colon involvement. In the sera of patients with ulcerative colitis no antibodies to cat-G or HLE were detectable. Only 8.3% of the patients with Crohn's disease had antibodies against proteinase 3 (C-ANCA). Our data indicate that cat-G among other myeloid lysosomal enzymes seems to be an important target antigen of antibodies in sera of patients with Crohn's disease. Cat-G antibodies might be helpful to distinguish Crohn's disease from ulcerative colitis.

Autoantibodies to the chromosomal protein HMG-17 in juvenile rheumatoid arthritis.

To determine the antibody profiles in sera from patients with juvenile rheumatoid arthritis (JRA). Immunoblotting using nuclear extracts and recombinant high-mobility group (HMG) nonhistone chromosomal proteins. Antibodies directed against HMG-17 were found in 47% of antinuclear antibody (ANA)-positive patients with pauciarticular-onset JRA and in 16% of ANA-positive patients with polyarticular-onset JRA. HMG-17 values of 6% and 8%, respectively, were detected in ANA-negative patients with JRA and in those with nonrheumatic diseases. There is evidence for a high prevalence of anti-HMG-17 antibodies in sera of patients with pauciarticular-onset JRA.

Antivinculin antibodies in sera of patients with immune thrombocytopenia and in sera of normal subjects

We have characterized a 120-Kd antigen that frequently reacts with serum antibodies from patients with immune thrombocytopenia or normal subjects. Immunoblots made after two-dimensional nonreduced/reduced sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) or two-dimensional isoelectric focusing/SDS-PAGE demonstrated that this 120-Kd protein has the same molecular weight under nonreduced or reduced conditions, is not a surface protein, and has an isoelectric point (pl) of 6.4 to 6.5. From these data, one likely candidate is the intracellular platelet protein, vinculin. Monoclonal antivinculin antibody reacts with this 120-Kd protein, and purified human platelet vinculin is bound by antibodies that recognize the 120-Kd protein. Therefore, we conclude that this 120-Kd protein is identical to vinculin. Data obtained from a sensitive enzyme-linked immunosorbent assay demonstrate the presence of naturally occurring antivinculin antibodies in many normal sera. However, the incidence of antivinculin antibodies in patient sera (67%; 55 of 82 sera) is significantly (P less than .01) higher than that in normal sera (40%; 32 of 80 sera), and there is a significant difference (P less than .05) between the mean levels of antivinculin antibodies in patient and normal sera. Whereas the levels of these antibodies in patient and normal sera overlap, 2 of 82 sera from patients with thrombocytopenia express unusually high levels of such antibodies. The pathologic significance of these antibodies remains to be determined.

Hepatitis C virus antibody secretion in vitro by peripheral blood lymphocytes.

A recombinant polypeptide corresponding to a virus-specific cDNA clone (c100-3) serves as the antigen for a hepatitis C virus (HCV) antibody assay. Previous investigations have shown an 80% prevalence of HCV antibodies in sera of patients suffering from post-transfusional chronic hepatitis non-A, non-B, but positive results were also obtained for 30 to 70% of sera from patients with chronic hepatitis B or autoimmune hepatitis. In this study we show that HCV antibodies are secreted by peripheral blood lymphocytes (PBL) in vitro. PBL from 12/35 patients with chronic non-A, non-B hepatitis and 1/6 patients with chronic active hepatitis B spontaneously secreted HCV antibodies in cell culture supernatants. The results were confirmed by neutralisation assay and ELISAs using recombinant and synthetic polypeptides derived from the c100-3 antigen and from the HCV core antigen. Two patients suffering from non-A, non-B hepatitis were negative for HCV antibodies in serum, but their PBL produced HCV c100-3 antibodies in vitro. PBL from patients suffering from autoimmune chronic hepatitis, primary biliary cirrhosis, toxic-liver injury and healthy blood donors did not produce antibodies to HCV c100 antigen irrespective of HCV antibody test results in their sera. Polyclonal B cell activation or mitogenic stimulation of T helper cells led to increased immunoglobulin synthesis by PBL in vitro, but did not lead to enhancement of specific HCV antibody production. In addition, HCV antibody production was not induced by these stimulation procedures in control lymphocytes. This spontaneous HCV antibody production in vitro suggests persistent antigenic stimulation of the B cells in vivo.

Human anti-interleukin 1α antibodies

Autoantibodies to the cytokine interleukin (IL)-1 alpha are frequently found in sera of apparently healthy humans. We have developed a sensitive radioimmunoassay (RIA) and an indirect enzyme-linked immunosorbent assay (ELISA) for the detection of human serum antibodies to IL-1 alpha at concentrations below 10 pmol/l. The RIA is based on coprecipitation of 125I-labelled human recombinant IL-1 alpha (rIL-1 alpha) by rabbit antibodies to human immunoglobulins. The ELISA is based on recovery of added rIL-1 alpha to serum samples and takes advantage of the fact that free human autoantibodies to IL-1 alpha in a dose dependent manner reduce recovery of added rIL-1 alpha. The assays correlate exceedingly well (r = 0.99, P less than 0.001). Their inter- and intraassay coefficients of variation were less than 30% and less than 5% (RIA) and less than 20% and less than 10% (ELISA). Both assays were used to measure the presence of anti-IL-1 alpha antibodies in sera of patients with various autoimmune diseases. Autoantibodies to IL-1 alpha were detectable in up to 75% of these sera, but the frequencies and titers varied considerably between individuals with different diseases.

Antibody in sera of patients infected with Trichomonas vaginalis is to trichomonad proteinases.

A recent report demonstrated the immunogenic character of the cysteine proteinases of Trichomonas vaginalis. It was of interest, therefore, to examine for the presence of serum anti-proteinase antibody among patients with trichomoniasis. An immunoprecipitation assay was used involving protein A-bearing Staphylococcus aureus first coated with the IgG fraction of goat anti-human Ig and then mixed with individual sera of patients to bind human antibody. These antibody-coated bacteria were then added to detergent extracts of T vaginalis. Bound immune complexes on S aureus were washed and solubilised for electrophoretic analysis on acrylamide copolymerised with gelatin for detection of proteinase activity. Sera from patients (50/50), but none from sera of normal, uninfected women, possessed IgG to numerous trichomonad cysteine proteinases. The presence of this serum anti-proteinase antibody disappeared after drug treatment and cure of patients of the T vaginalis infection. The commonality of the anti-proteinase antibody in the sera of patients with trichomoniasis provided evidence for the expression of the same repertoire of parasite proteinases during infection. These observations have important implications for the in vivo relevance of the proteinases and indicate that strategies to use a specific serum antibody response for diagnosis of this infection may be possible.

Isolation and characterization of a thermolabile β-2 macroglycoprotein (‘thermolabile substance’ or ‘Hakata antigen’) detected by precipitating (auto) antibody in sera of patients with systemic lupus erythematosus

A novel thermolabile beta-2 macroglycoprotein ('thermolabile substance' (TLS) or 'Hakata antigen' (HA], which was detected by the precipitating (auto) antibodies of patients with systemic lupus erythematosus, was isolated and characterized. The purification procedure entailed the following steps: isoelectric precipitation in the range between pH 5.2-6.1, hydroxyapatite absorption chromatography, 35% saturated ammonium sulfate precipitation, Sephadex G-200 gel filtration, Pevikon block electrophoresis, lentil lectin affinity chromatography and immobilized rabbit anti-human whole serum IgG column chromatography. Utilizing these procedures, 0.1 mg of HA was purified from 3 1 of pooled human serum. The molecular mass of HA was determined as 650 kDa by Sepharose 4B gel filtration. On SDS-PAGE analysis, HA showed a single band at 35 kDa under reduced conditions and numerous ladder bands between 35 kDa to more than 300 kDa under nonreduced conditions. On analytical ultracentrifugation, HA gave a molecular mass of 520 kDa with a single meniscus and a sedimentation constant of 12.0. The amino acid and carbohydrate analysis of reduced and S-pyridylethylated HA revealed that it contained five residues of hydroxyproline and an N-linked type sugar chain.

The phenotypically variable surface protein of Trichomonas vaginalis has a single, tandemly repeated immunodominant epitope

Trichomonas vaginalis is a sexually transmitted protozoan parasite that undergoes phenotypic variation for numerous surface proteins. A monoclonal antibody (MAb) was used to isolate an approximately 400-bp cDNA encoding a fragment of an important phenotypically varying immunogen of T. vaginalis (Mr = 270 kDa; P270). The MAb completely inhibited the binding of P270 by antibody in sera of patients and by antibody in monospecific antiserum obtained toward purified P270, indicating that P270 contained only one immunodominant epitope. Hydrophilicity plot analysis of the deduced amino acid sequence of the recombinant protein predicted the hexapeptide sequence DREGRD as the antigenic determinant of P270. Synthetic peptides synthesized to this region demonstrated that the amino acid sequence DREGRD is important for antibody binding. Seven adjacent amino acids also contributed substantially to maximal recognition of the epitope by the MAb. A single transcript of approximately 9.5 kb, a size compatible with the reported Mr of the immunogen, hybridized to the cDNA in Northern blots of total RNA from T. vaginalis. DNA sequence and Southern blot analysis determined the epitope to be encoded by a 339-bp unit, which was found to be tandemly repeated at least 12 times within the single-copy gene. This 12-mer unit would only constitute approximately 50% of the protein, yet it is responsible for all of the serum antibody to the immunogen produced by animals and humans. The epitope sequence was found in all fresh and long-term-grown organisms examined to date, demonstrating the stability and conservation of this gene.

Antinuclear antibodies in sera of patients with recurrent pregnancy wastage

Four groups of women were studied to determine whether low-level antinuclear antibody titers are associated with a higher risk for pregnancy loss. Group A consisted of 30 patients with a history of unexplained fetal losses. Group B consisted of 30 women with "explained" fetal losses (e.g., uterine septum or luteal phase defect). Ages and number of losses were comparable between the women in groups A and B. Group C consisted of 61 healthy pregnant women. Group D involved 61 healthy nonpregnant women of reproductive age. In groups A and B, 40% and 53.3% of the respective patients had antinuclear antibody titers >_1 : 40. In groups C and D the frequencies of positive antinuclear antibody titers were 8.2% and 5.6%, respectively. This study demonstrates a high prevalence of low-titer antinuclear antibody-positive serum in patients with explained and unexplained pregnancy losses. (Am J Obstet Gynecol 1990;163:1493-7.)

Mapping of B-cell epitopes of the human hepatitis B virus X protein

The immune response to the X protein of human hepatitis B virus (HBV) was studied by epitope mapping by using a set of MS2-HBx fusion proteins and synthetic peptides. Antibodies in sera of patients with acute and chronic HBV infection showed a multispecific immune response. Each serum contained antibodies to a different set of epitopes, which taken together cover most of the HBx sequence. Some of the epitopes were detectable only by immunoblotting with fusion proteins; others were detectable only by an enzyme-linked immunosorbent assay (ELISA) with synthetic peptides. The carboxy-terminal half of the HBx protein was preferentially recognized by antibodies from patients with chronic hepatitis and contained a short immunodominant antigenic region with at least two major nonoverlapping epitopes. Anti-HBx antibody titers as revealed by peptide ELISAs were highest and most frequent in patients with chronic hepatitis and usually low in acutely infected patients and asymptomatic carriers. The data demonstrate a remarkable qualitative and quantitative heterogeneity of the humoral HBx immune response which can be monitored by HBx-specific peptide ELISAs. Such tests may become useful diagnostic tools.

Cross-reactivity between the EBNA-1 p107 peptide, collagen, and keratin: Implications for the pathogenesis of rheumatoid arthritis

An unusually heavy load of Epstein—Barr virus (EBV) infection and autoimmunity to collagen are believed to be contributing factors to the pathogenesis of rheumatoid arthritis (RA). The present report presents data showing that p107, the major epitope of the EBV-encoded EBNA-1 antigen, cross-reacts with denatured collagen (DC) and keratin (K), suggesting a new likely link among RA, EBV-1, and these autoantigens. A radio-immunoassay using antigen-coated microtiter plates was used to demonstrate antibodies in sera of patients with RA and sera of healthy donors against p107, DC, and K. Specificity of the antibodies was ascertained by inhibition tests with the homologous antigens. Cross-reactivity among anti-p107, anti-DC, and anti-K antibodies was assayed by the ability of a given antigen to block the binding of nonpurified or affinity-purified antibodies to plates coated with another antigen. Most of the sera contained antibodies to all three antigens, but only anti-DC antibodies were present in higher titers in RA sera. Preincubation of sera with p107 appreciably reduced their binding to plates coated with DC or K. On the other hand, preincubation with DC (in solution or bound to Sepharose) did not result in consistent reduction of anti-p107 titers. Tests with affinity-purified antibodies revealed the existence of two antibodies populations, one of which reacted preferentially with p107, the other with DC. The cross-reactivity of the anti-p107 antibodies with DC and K suggests that such antibodies, produced by RA patients following persistent stimulation with EBV, might react in vivo with collagen (and keratin) exposed in previously damaged areas and thus reinforce the disease process.

Pemphigoid, pemphigus and desmoplakin as antigenic markers of differentiation in normal and tumorigenic mouse keratinocyte lines.

The expression of differentiation stages in a murine epidermal cell transformation model has been investigated as a basis for studies of chemically-induced differentiation. Antibodies in sera of patients with the autoimmune diseases bullous pemphigoid and pemphigus vulgaris exhibit specific reactivity to antigenic determinants of basal and spinous cells, respectively, in sections of mouse and human epidermis. In addition, spinous cells in epidermis are reactive with a mouse monoclonal antibody to desmoplakin, a desmosomal component immunologically distinct from pemphigus. These antibodies were used to identify and attempt to quantify keratinocyte subpopulations in culture based on differentiation stage. Epidermal cell lines were cultured under conditions which favour proliferation (0.02 to 0.04 mM extracellular Ca2+, i.e. low Ca2+ conditions) or differentiation (0.1 mM to 1.4 mM Ca2+), as previously shown using primary cultures of mouse keratinocytes. Two independently-derived normal keratinocyte lines demonstrated Ca2(+)-dependent reactivity with pemphigoid and pemphigus antiserum, like that which has been observed in primary cultures. Furthermore, a Ca2+ and time-dependent reactivity with the three antisera was also observed in a papilloma cell line (derived from one of the normal cell lines after treatment in vitro with 7,12-dimethylbenz[alpha]anthracene). Papilloma cells cultured under conditions of low extracellular Ca2+ were comprised of three subpopulations: cells reactive only with pemphigoid anti-serum, cells reactive only with desmoplakin antibody. However, like the normal cell lines, papilloma cells underwent a transition to predominantly a spinous cell population (i.e. reactive with pemphigus and desmoplakin antibody) in response to extracellular Ca2+. A slower loss of pemphigoid antibody reactivity was noted in papilloma cells, consistent with an abnormal regulation of differentiation. The attempt to characterize these dynamic transitions from basal to spinous cell subpopulations in culture was considered to be prerequisite for the use of the model to investigate differentiation-inducing agents in carcinoma therapy.

Discrimination of HIV-1 and HIV-2 infection based on recombinant immunoblots

Recombinant polypeptides representing various parts of structural proteins of HIV-1 and HIV-2 were expressed in E. coli. Fragments of the transmembrane proteins gp41 of HIV-1 (HTLV-IIIB) and gp38 of HIV-2 (LAV-2 ROD) proved to be highly antigenic in the immunoblot test system. Each protein was found to be suitable for detection and differentiation of antibodies in sera of patients infected with HIV-1 or HIV-2. Sera of 100 patients from West-Germany, which were confirmed as positive for HIV-1 antibodies, reacted clearly with the HIV-1 recombinant antigen (fpOE-6); no or only weak immune reactions were seen when the analogous recombinant HIV-2 antigen (fpOE-T) was used in the same immunoblot test. An inverse reaction pattern was found with 7 sera from Africa which, by conventional means, were proved to be HIV-2 antibody positive. These sera specifically reacted with the homologous HIV-2 fusion protein and no or only weakly stained bands were identified on the analogous strip with the HIV-1 antigen (fpOE-6).

Higher incidences of anti-SS-A/Ro and anti-SS-B/La autoantibodies in Japanese patients with autoimmune disorders--studies of antigens and antibodies using the immunoblotting method.

A specific and sensitive assay was performed to detect both anti-SS-A/Ro and anti-SS-B/La antibodies in sera of patients with autoimmune diseases, including systemic lupus erythematosus (SLE), progressive systemic sclerosis (PSS), Sjögren's syndrome (SS), discoid lupus erythematosus (DLE), mixed connective tissue disease (MCTD), generalized morphea (GM), and dermatomyositis (DM). The SS-A/Ro and SS-B/La antigens were prepared from human spleen (HSE) and cultured human cell line (KB cells, KBE), white rabbit thymus extract (RTE) was used as the SS-B/La antigen marker. The antigens were partially purified by DEAE cellulose column chromatography. Immunoblotting showed that the SS-A/Ro antibody reacts mainly with the 58-kDa peptide of the partially purified antigen. Sera containing both the SS-A/Ro and SS-B/La antibodies reacted with the 40-kDa peptide of RTE, and the 58-kDa, 42-kDa, and 40-kDa peptides of HSE and KBE. We found that some of the SS-A/Ro antisera could further react with the 64-kDa peptide of HSE and KBE. The 58-kDa peptide is rich in its cytoplasmic fraction of KB cells, and the 4-kDa peptide in nucleoplasmic fraction. The KB cell line is a better source of the antigens than human spleen extract. The immunoblotting method clearly showed that the positivity rates of SS-A/Ro and/or SS-B/La autoantibodies were higher in sera from Japanese patients with SLE compared with titers reported for Caucasians but not in sera from healthy volunteers.