A 52-kD protein is a novel component of the SS-A/Ro antigenic particle

Anti-SS-A/Ro autoantibodies are found in the sera of patients with Sjogren's syndrome (SS) and SLE. In the course of analyzing 61 SS patients for their autoantibody profiles, we found that 42 were positive for anti-SS-A by double diffusion in agarose and demonstrated precipitin lines identical to that produced by a prototype anti-SS-A serum. Further analysis of these SS-A antibody-positive sera by Western blotting of cell extracts revealed that 21 sera reacted with two proteins of 60 and 52 kD, 13 sera reacted with 52-kD protein, two detected only 60 kD, while six were nonreactive. Affinity-purified anti- 60-kD and anti-52-kD antibodies reacted exclusively with their corresponding antigens. Partial proteolysis of these proteins did not reveal common degradation fragments. Thus the 52- and 60-kD proteins were found to be antigenically and apparently structurally distinct from each other. They were also distinct from 48-kD SS-B/La protein. In immunoprecipitation using labeled cell extracts, affinity-purified anti- 52-kD antibodies brought down the 52-kD protein as well as the 60-kD band. In [32P]orthophosphate-labeled HeLa cell extract both antibodies precipitated the same spectrum of small RNAs (hYl-5). In indirect immunofluorescence, anti-52-kD and anti-60-kD antibodies immunolocalized in similar subcellular structures and showed similar punctate nuclear staining patterns. Western blot analysis revealed that both proteins were present in lymphocytic as well as epithelial human cell lines tested. The data above define a new antigen of 52 kD which is another component of the SS-A particle and is associated in complex formation with the previously reported 60-kD protein.     

Characterization of glycoprotein antigen (45 kD) of Aspergillus fumigatus

An immunodominant glycoprotein antigen (45 kD) from Aspergillus fumigatus was purified and characterized. The purified antigen exhibited strong precipitin reaction with the sera of allergic bronchopulmonary aspergillosis (ABPA) patients. Enzyme-linked immunosorbent assay (ELISA) and Western blot results revealed strong binding of gp 45 with IgG and IgE antibodies of ABPA patients. Three monoclonals of IgM isotype, raised against a glycoprotein fraction of A. fumigatus, recognized 45 and 55 kD antigens. These results suggest the presence of common epitopes in these antigens. The protein to carbohydrate ratio of purified antigen was observed to be 1.4: 1.0. Further analysis by gas liquid chromatography revealed the presence of glucose, mannose and glucosamine residues in a 4 : 3 : 1 ratio. Deglycosylation of N-linked sugars of gp 45 with N-glycosidase-F resulted in a 27 kD band on sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Neuraminidase treatment destroyed the IgE binding activity of the antigen but IgG binding activity was retained. The IgG binding activity on the other hand was lost on treatment with pronase. The major IgG binding epitope of this glycoprotein antigen may therefore be in the protein part of the antigen. The purified 45 kD antigen displayed protease activity at alkaline pH. It was inhibited by PMSF and ethylene diamine tetraacetic acid (EDTA). Proteolytic activity of the antigen may contribute significantly to pathogenesis by destroying the elastin present in the lung tissue.     

免疫印迹检测抗眼肌抗体

用含ＴｒｉｔｏｎＸ－１００及脱氧胆酸钠的ＴＤＯＣ缓冲液自牛眼肌提取了眼肌细胞膜抗原，建立了抗眼肌多肽抗体的免疫印迹检测法。     

Cloning and expression of Trypanosoma cruzi ribosomal protein P0 and epitope analysis of anti-P0 autoantibodies in Chagas'' disease patients

Chagas' disease, caused by the intracellular protozoan parasite Trypanosoma cruzi, is a major cause of heart failure in endemic areas. Antigenic mimicry by T. cruzi antigens sharing epitopes with host macromolecules has been implicated in the pathogenesis which is thought to have a significant autoimmune component. We report herein on the cloning and characterization of a full-length cDNA from a T. cruzi expression library encoding a protein, TcP0, that is homologous to the human 38-kD ribosomal phosphoprotein HuP0. The T. cruzi P0 protein shows a clustering of residues that are evolutionarily conserved in higher eukaryotes. This includes an alanine- and glycine-rich region adjacent to a highly charged COOH terminus. This "hallmark" domain is the basis of the crossreactivity of the highly immunogenic eukaryotic P protein family. We found that T. cruzi-infected individuals have antibodies reacting with host (self) P proteins, as well as with recombinant TcP0. Deletion of the six carboxy-terminal amino acids abolished the reactivity of the T. cruzi infection sera with TcP0. This is similar to the specificity of anti-P autoantibodies described for a subset of patients with systemic lupus erythematosus (SLE) (Elkon, K., E. Bonfa, R. Llovet, W. Danho, H. Weissbach, and N. Brot. 1988. Proc. Natl. Acad. Sci. USA. 85:5186). These results suggest that T. cruzi P proteins may contribute to the development of autoreactive antibodies in Chagas' disease, and that the underlying mechanisms of anti-P autoantibody may be similar in Chagas' and SLE patients. This study represents the first definitive report of the cloning of a full-length T. cruzi antigen that mimics a characterized host homologue in structure, function, and shared antigenicity.     

SS-56, a novel cellular target of autoantibody responses in Sjögren syndrome and systemic lupus erythematosus

Certain autoimmune disorders, including Sj?gren syndrome (SS) and systemic lupus erythematosus (SLE), are characterized by autoantibodies against the Ro/SSA and La/SSB cellular antigens. Although the implication of these autoantibodies in disease pathogenesis is still unclear, it is believed that the aberrant responses against autoantigens may extend to other proteins that are not yet well defined. In an attempt to analyze the regulated gene expression in lymphocytes by an HIV-suppressive immunomodulator, we have identified and cloned a novel gene encoding a 56-kDa protein, named SS-56, which is structurally related to the 52-kDa Ro/SSA antigen. The new protein showed primarily perinuclear cytoplasmic localization, and recombinant SS-56 was found to react in ELISA with sera from most patients with SS or SLE. Western blot analysis confirmed the autoantigenic nature of native SS-56 in extracts from HeLa cells. Interestingly, the incidence of antibodies to SS-56 was associated with visceral complications in SLE, and roughly half of the 17 SS or SLE patients with no detectable antibodies to SSA and SSB antigens presented measurable antibodies against recombinant SS-56. Thus, SS-56 represents a new member of the SS family of autoantigens and could become an additional and important diagnostic marker for SS and SLE.     

Vaccination-induced variation in the 140 kD merozoite surface antigen of Plasmodium knowlesi malaria

Immunity to 143/140 kD schizont antigens of a monkey malaria, Plasmodium knowlesi, provides partial protection to lethal malaria infection in rhesus monkeys challenged with uncloned parasites. To determine the capacity of a cloned parasite to generate variants of the 143/140 kD antigens, immunized monkeys were challenged with a clone of P. knowlesi. Parasites recovered 8 d after inoculation with a cloned parasite retained the 143/140 kD antigens. Parasites recovered 30 d after challenge had undergone changes in the 143/140 kD antigens. Antibodies that block erythrocyte invasion in vitro of the inoculum parasites did not inhibit invasion of erythrocytes by two isolates recovered from the immunized monkeys. An isolate from one monkey recovered on day 30 contained clones expressing new 76/72 kD antigens reactive with rabbit antiserum against the 143/140 kD proteins, and other clones expressing no antigens crossreactive with antisera against the 143/140 kD proteins. An isolate from another monkey obtained 59 d after challenge expressed new antigens of 160/155, 115/113, and 87/85 kD. Using monoclonal antibodies, we found that epitopes were lost from the variant proteins, but we were unable to determine whether new epitopes had appeared. We conclude that clones of P. knowlesi can rapidly vary antigenic determinants on the 143/140 kD proteins in animals immunized with these antigens.     

Anti-idiotypic antibodies prevent the serologic detection of antiribosomal P autoantibodies in healthy adults.

A subset of SLE patients has serologically detectable autoantibodies to the ribosomal P proteins (anti-P). We reported the discovery of covert anti-P antibodies and their masking IgG-inhibitory antibodies in the sera of healthy adults. The aim of this study was to determine if these IgG-inhibitory antibodies are anti-idiotypic antibodies (anti-Ids). IgG and IgG-depleted fractions of plasma from two healthy adults were assayed for inhibition of anti-P F(ab')2 binding to the ribosomal P proteins in immunoblot. Anti-P antibody activity was completely inhibited by plasma IgG, whereas there was no inhibition by IgG-depleted plasma. IgG-inhibitory antibodies recognized a cross-reactive epitope among anti-P from different SLE patients. Plasma IgG from one healthy adult was depleted of pepsin agglutinators and generic anti-F(ab')2 antibodies by adsorption with an affinity column prepared with normal IgG F(ab')2. Unretained IgG bound exclusively to anti-P F(ab')2 in ELISA. Using four affinity columns, we isolated IgG anti-Ids to anti-P antibodies from four healthy adults. These purified anti-Ids bound to anti-P F(ab')2 from a healthy adult and SLE patients. They did not bind to F(ab')2 fragments prepared from normal IgG or anti-dsDNA. Ribosomal antigens blocked this anti-Id-Id interaction. Purified anti-Ids inhibited the binding of anti-P F(ab')2 from patients to ribosomal P proteins. SLE patients without overt anti-P antibodies also possessed IgG anti-Ids to anti-P antibodies. We conclude that IgG-inhibitory antibodies are anti-Ids to anti-P antibodies, and are directed to public idiotopes on anti-P antibodies. These anti-Ids may be part of an Id network that regulates anti-P antibody expression, and perhaps pathogenicity.     

Characterization of antibody response in patients with Borrelia meningitis

Western blot analysis was used to characterize the antibody response of 38 patients with Borrelia meningitis to different strains of Borrelia spirochetes. Eight strains of Borrelia spirochetes were analysed by SDS-PAGE which showed major proteins of 60, 41, 31·5–34 and 22–23 kD. Immunoblots of all sera, and all except one CSF from patients with clinically active disease showed IgG and/or IgM antibodies to at least one Borrelia protein. Antibodies to a 41 kD protein was the first to appear and patients with a longer duration of neurological disease had antibodies to as many as 19 different proteins. Some of the 40 controls showed weak bands, in some cases with the same location as in the Borrelia infected patients. In comparison with an ELISA assay based on a whole cell sonicate as antigen, western blot was more sensitive in detecting an early antibody response, especially in serum. We conclude that Western blot might be used as a complement for immunological diagnosis of Borrelia infection in selected cases with low or border-line ELISA titers. However, a more sensitive/specific ELISA assay might be developed with a single protein as antigen.     

Species-specific sera against surface antigens of Bacillus anthracis strains

The species-related specificity of sera against 94-KD proteins isolated from culture filtrates of B. anthracis strains with different levels of virulence plasmids was studied to determine whether they might be used to identify the pathogen of anthrax. Sera against fractions 1 of culture filtrates of B. anthracis strains CTI (pXO1+ pXO2-), 81/1TR (pXO1- pXO2-), Davies (pXO1- pXO) separated by gel chromatography on Sephacryl S-300 were examined. In the gel immunodiffusion test with growing cultures, the sera exhibited non-identical antigens and differed in the presence of antibodies to antigens of related bacilli. The sera against fractions 1 of culture filtrates of toxin-producing and plasmidless strains displayed antigens produced only by B. anthracis strains into nutrient agar. Electroimmunotransblotting revealed that they contained antibodies mainly to 94-kD proteins and failed to react with B. cereus proteins with a molecular weight of 94 kD and with B. thuringiensis proteins with a molecular weight of 97 kD, which were extracted from autonomous cells. In the immunofluorescence test, immunoglobulins of sera against fractions 1 of culture filtrates of three strains stained autonomous cells and spores of 23 B. anthracis strains with different levels of virulence plasmids. In working dilutions, they did not react with antigens of 18 strains of related bacilli, which presents a possibility of using them for species identification of B. anthracis.     

采用血清蛋白质组学方法筛选能诱发自身抗体的鼻咽癌相关抗原

目的 采用血清蛋白质组学方法筛选能诱发机体产生自身抗体的鼻咽癌(NPC)相关抗原,以便为NPC诊断和治疗提供候选标志.方法 收集19份NPC组织,采用二维凝胶电泳(2-DE)技术分离组织总蛋白质,每份组织样本同时做3块2-DE胶,其中将1块2-DE胶作为制备胶进行考马斯亮蓝染色,另2块2-DE胶采用半干式电转法将胶中的蛋白转至PVDF膜上,并分别与NPC患者自身的血清和健康人血清进行2-DE免疫印迹分析,识别能与多数NPC患者血清反应而不与或很少与健康人血清反应的蛋白质点,再从制备2-DE胶中切取相应蛋白质点,进行基质辅助激光解吸电离飞行时问质谱(MOLDI-TOF MS)和电喷雾电离四级杆飞行时间质谱(ESI-Q-TOF MS/MS)分析,获取肽质量指纹图和肽序列标签,数据库搜索鉴定蛋白质.结果 鉴定了13个能诱发机体产生自身抗体的NPC相关抗原:热休克蛋白70(HSP70)、人血清白蛋白(HAS)、热休克蛋白60(HSP60)、细胞角蛋白15(CK 15)、亮氨酸氨基肽酶(LAP 3)、α-烯醇化酶(α-enolase)、ErbB3结合蛋白(EBP1)、细胞角蛋白19(CK 19)、核糖体蛋白P0(RPP 0)、丙酮酸脱氢酶E1(PDE 1)、GTP结合调节蛋白(GNBP)、抗增殖蛋白(prohibitin)和Rho GDP解离抑制因子2(Rho-GDI 2),13种蛋白质点在21%的鼻咽癌患者中可见,而健康人中缺乏或出现频率较低.结论 本研究筛选到13个NPC相关抗原,这些抗原能诱导患者产生自身抗体,这些抗体有可能成为NPC诊断标志和治疗靶标.     

Reactivity of recombinant treponema pallidum (r-Tp) antigens with anti-Tp antibodies in human syphilitic sera evaluated by ELISA

We evaluated the immunoreactivity of recombinant Treponema pallidum (r-Tp) antigens with human sera by indirect enzyme-linked immunoabsorbant assay (ELISA). We expressed antigens with a molecular weight (MW) of 17KDa, 15KDa, 47KDa, and 42KDa, which are believed to be major immunoreactive membrane proteins of Tp cells. The expressed proteins were described by adding the prefix M, S, and G to the corresponding Tp antigens, namely, mature antigens, signal sequence containing antigens, and glutathione s-transferase (GST)-fused antigen in this report. A rather high expression occurred for M47 and S42 proteins in the Escherichia coli system, whereas for M15 and M17 proteins, a poor expression was observed. However, a fairly high expression occurred for G15 and G17. Thus expressed proteins were purified by means of chromatographies to a level of > 95%, and the purified proteins were found to be reactive with TPHA positive serum by Western blotting (WB). An ELISA performed with a serum of 1/1000 dilution using these purified antigens for coating on the solid phase showed that G17 antigen was more effective in detecting syphilis antibodies in human serum than M47, S42, and G15. There was a good consistency between ELISA and TPHA, whereby the cutoff indexes (CI) on ELISA showed a correlation coefficient of 0.7276 in logarithmic TPHA titers. J. Clin. Lab. Anal. 11:315–322, 1997. © 1997 Wiley-Liss, Inc.     

Neutrophil-binding immunoglobulin G in systemic lupus erythematosus.

The objectives of these studies were to quantify the amounts of immunoglobulin (Ig)G bound to peripheral blood neutrophils from patients with systemic lupus erythematosus (SLE) and to determine the contributions of soluble immune complexes or anticell antibodies to the levels of IgG neutrophil-binding activity in SLE sera. Neutrophil-bound IgG, determined by a sensitive antiglobulin inhibition assay, was elevated in 7 out of 14 SLE patients compared with values obtained in 23 normal controls. The levels of IgG neutrophil-binding activity in sera were elevated in 22 of 38 patients with SLE over the values seen with 36 normal sera. No correlation was found between the peripheral blood neutrophil counts in the SLE patients and the values for IgG adherent to the cells or serum cell-binding activity. The sera from 18 patients with SLE were fractionated by gel filtration. Elevated levels of IgG neutrophil-binding activity were found in 11 of the 18 G-200 excluded pools and in 13 of the G-200 IgG pools. In nine sera elevated levels were observed in both pools. F(ab')2 fragments of IgG from SLE sera bound to normal polymorphonuclear leukocytes in greater amounts than F(ab')2 fragments of IgG from normal sera. A significant correlation existed between the values of IgG neutrophil-binding activity found in SLE sera and those obtained with both the G-200 excluded and IgG pools. Sucrose density gradient fractionation of four sera from SLE patients confirmed the presence of both large (greater than 19S) and intermediate-sized (7S-19S) cell-binding immune complexes as well as of monomeric IgG antibodies to neutrophils. The levels of IgG neutrophil-binding activity in the SLE sera correlated well with the results obtained with the Raji cell assay for immune complexes as well as with the titer of antibodies to nuclear antigens. These data indicate that circulating neutrophils from patients with SLE commonly have increased amounts of cell-bound IGG. The elevated levels of IgG neutrophil-binding activity in the sera of these patients are caused by both soluble immune complexes and antibodies reactive with neutrophils.     

Insights into native epitopes of proliferating cell nuclear antigen using recombinant DNA protein products

A cDNA clone encoding full-length human proliferating cell nuclear antigen (PCNA) was used to generate a panel of in vitro translated labeled protein products with COOH-terminal deletions and to construct a set of fusion proteins with COOH- and NH2-terminal deletions. A rabbit antiserum raised against an NH2-terminal peptide, a well-characterized murine monoclonal antibody (mAb), and 14 human lupus sera with autoantibody to PCNA were analyzed for their reactivity with the constructs using both immunoprecipitation and immunoblotting techniques. The rabbit antiserum reacted in immunoprecipitation and immunoblotting with constructs containing the appropriate NH2-terminal sequence and mAb reacted with a sequence from the midregion of PCNA. These experimentally induced antibodies also reacted with 15-mer synthetic peptides in enzyme-linked immunosorbent assay (ELISA). In contrast, none of the lupus sera reacted with synthetic peptides in ELISA. 9 of the 14 lupus sera also failed to react in Western immunoblotting with any recombinant fusion protein, although they all immunoprecipitated in vitro translated full-length protein. Four of the nine had variable patterns of immunoprecipitation with shorter constructs. The remaining five lupus sera were able to immunoprecipitate translation products as well as Western blot recombinant fusion proteins. From analysis of the patterns of reactivity of human lupus sera, it was deduced that the apparent heterogeneity of human autoantibodies to PCNA could be explained by immune response to highly conformational epitopes. These observations demonstrate that there might be special features in "native" epitopes of intranuclear antigens that are recognized by autoantibodies, and that these special features of native epitopes might not be present in prepared antigen used for experimental immunization. These features may be related to protein folding or to association of the antigen with other intranuclear proteins or nucleic acids, as might occur with antigens that are components of subcellular particles.     

两种方法联合检测自身免疫性疾病中ANCA的临床意义

目的评价间接免疫荧光法（IIF）和免疫印迹法检测抗中性粒细胞胞质抗体（ANCA）的临床意义。方法采用IIF和免疫印迹法联合对126例自身免疫性疾病患者的血清进行ANCA检测。结果在126例患者中类风湿关节炎（RA）、韦格纳肉芽肿瘤（WG）、皮肌炎（DM）和过敏性紫癜患者血清检测cANCA阳性与PR3-ANCA阳性是一一对应的;而在51例SLE患者中,有17例（33.3%）pANCA阳性,7例（13.7%）骨髓过氧化物酶（MPO）-ANCA阳性;在29例RA中3例（10.3%）pANCA阳性,而4例（13.7%）MPO-ANCA阳性。WG和ANCA相关性血管炎患者检测ANCA阳性率较高,分别为87.5%和93.7%。结论IIF一般情况下可以作为临床常规检测ANCA的筛选试验,免疫印迹法可以作为特异ANCA确证试验。二者联合应用可以提高ANCA的检出率,减少ANCA的误诊率。     

Human monoclonal antibodies: analysis of two antibodies derived from lymphocytes of a patient with acute rheumatic fever.

Human monoclonal antibodies were produced by fusion of peripheral blood lymphocytes from a patient with acute rheumatic fever, with the HGPRT-non-secreting murine (Balb-c) cell line SP2/0Ag14. Heterohybridomas were selected by screening against rheumatic fever-associated group A streptococci using an ELISA, and against paraffin wax-embedded human heart sections using an immunoperoxidase technique. Two human IgM monoclonal antibodies were selected for further analysis by Western blotting and ELISA. Both antibodies demonstrated multispecificity by immunoblotting and ELISA. One of the monoclonals bound to 48 kD and 83 kD bands common to group A streptococcal and heart antigen preparations. Both human monoclonal antibodies bound to a 43 kD constituent band common to human heart and sarcolemma membrane extract. Inhibition studies performed using a competitive solid phase immunoassay confirmed shared epitopes between group A streptococci and human heart. The significance of these monoclonal antibodies to the pathogenesis of rheumatic fever is uncertain.     

Radioimmunoassay for the carboxy-terminal cross-linking domain of type IV (basement membrane) procollagen in body fluids. Characterization and application to collagen type IV metabolism in fibrotic liver disease.

The carboxy-terminal cross-linking domain (NCl) of type IV procollagen was isolated from human placenta and used for the production of polyclonal and monoclonal antibodies. Purity of the antigen and specificity of the antibodies were verified by Western blotting and radioimmunoassays. A radioimmunoassay was developed using rabbit antiserum. Intra- and interassay coefficients of variation were 4.7% and 5.8%, respectively; recovery of NCl added to serum and bile was 95-105%. NCl concentration in sera of healthy volunteers was 6 +/- 2.9 ng/ml (mean +/- 2.5 SD) and was elevated up to 18 ng in sera of patients with autoimmune or metastatic tumor disease and up to 240 ng in sera of patients with fibrogenic liver disease. Substantial amounts of antigen were also found in bile, urine, and ascites. 67% of serum antigens eluted from an agarose A5M column with an apparent molecular weight of 60 kD and 23% with a molecular weight of 90 and 150 kD, well below the molecular weight of type IV procollagen (550 kD). Serum NCl is apparently derived from the degradation of basement membrane collagen. The time course of NCl concentrations in sera of patients with fibrogenic liver disease showed no correlation with the serum concentration of the amino-terminal procollagen type III peptide, a marker of hepatic collagen biosynthesis. A decline of serum NCl levels along with elevated serum procollagen type III peptides apparently indicates bad prognosis in fibrogenic liver disease. The radioimmunoassay for NCl is a useful tool for studying type IV collagen metabolism in conditions causing remodeling or breakdown of basement membranes.     

Small, clonally variant antigens expressed on the surface of the Plasmodium falciparum-infected erythrocyte are encoded by the rif gene family and are the target of human immune responses

Disease severity in Plasmodium falciparum infections is a direct consequence of the parasite's efficient evasion of the defense mechanisms of the human host. To date, one parasite-derived molecule, the antigenically variant adhesin P. falciparum erythrocyte membrane protein 1 (PfEMP1), is known to be transported to the infected erythrocyte (pRBC) surface, where it mediates binding to different host receptors. Here we report that multiple additional proteins are expressed by the parasite at the pRBC surface, including a large cluster of clonally variant antigens of 30-45 kD. We have found these antigens to be identical to the rifins, predicted polypeptides encoded by the rif multigene family. These parasite products, formerly called rosettins after their identification in rosetting parasites, are prominently expressed by fresh isolates of P. falciparum. Rifins are immunogenic in natural infections and strain-specifically recognized by human immune sera in immunoprecipitation of surface-labeled pRBC extracts. Furthermore, human immune sera agglutinate pRBCs digested with trypsin at conditions such that radioiodinated PfEMP1 polypeptides are not detected but rifins are detected, suggesting the presence of epitopes in rifins targeted by agglutinating antibodies. When analyzed by two-dimensional electrophoresis, the rifins resolved into several isoforms in the pI range of 5.5-6.5, indicating molecular microheterogeneity, an additional potential novel source of antigenic diversity in P. falciparum. Prominent polypeptides of 20, 22, 76-80, 140, and 170 kD were also detected on the surfaces of pRBCs bearing in vitro-propagated or field-isolated parasites. In this report, we describe the rifins, the second family of clonally variant antigens known to be displayed by P. falciparum on the surface of the infected erythrocyte.     

Detection of antibodies against 60-, 65- and 70-kDa heat shock proteins in paediatric patients with various disorders using Western blotting and ELISA.

BACKGROUND: We examined antibodies against 60-, 65- and 70-kDa heat shock proteins (HSPs) in paediatric healthy individuals, patients with juvenile idiopathic arthritis (JIA) and those undergoing allogeneic stem-cell transplantation for various malignant and non-malignant diseases. METHODS: Western blotting and ELISA were used to examine HSP-directed humoral immune responses. RESULTS: Using ELISA we detected anti-Hsp60, -Hsp65 and -Hsp70 IgG antibodies in patient sera before, during and after conditioning and at all post-transplant times, as well as in JIA patients and controls. Western blotting showed positivity for anti-Hsp60 and anti-Hsp65 antibodies in all samples with a HSP concentration of 0.5 microg/lane. However, anti-Hsp70 antibodies were not detected at all when both sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and native PAGE were used, except for one JIA patient, for whom a positive signal was only achieved in native PAGE when Hsp70 was increased to 2 microg/lane and serum dilution decreased to 1:10. CONCLUSION: Western blotting is convenient for the detection of anti-Hsp60 and anti-Hsp65 antibodies, but it is not sensitive enough for the detection of anti-Hsp70 antibodies. ELISA, which is more sensitive, might be preferentially used to screen anti-Hsp60, -Hsp65 and -Hsp70 antibodies in sera of children with various disorders.     

Chemiluminescent immunoassays: Discrimination between the reactivities of natural and human patient antibodies with antigens from eukaryotic pathogens,Trypanosoma cruzi and Paracoccidioides brasiliensis

Quantitative chemiluminescent enzymelinked immunosorbent assay (ELISA) and dot-blotting procedures were developed to evaluate the reactivity of human antibodies with crude antigens and purified molecules of parasites and fungi, mainly Trypanosoma cruzi and Paracoccidioides brasiliensis. Reproducible, highly sensitive, and strictly doseresponding results were obtained, with the specificity depending on the kind of antigen used. Mixed antigens (epimastigote membrane and HIV-1 heptapeptide) applied in dots could be independently recognized by specific sera. Purified antigens (T. cruzi F2/3 and P. brasiliensis gp43) at very small concentrations gave specific reactions with patients' sera diluted ≥1:1,000 and were very poorly reactive or unreactive with natural antibodies using the chemiluminescent immunoassays. P. brasiliensis crude antigen Fava Netto polysaccharide antigen (FNPA) contained peptide epitopes recognized by natural antibodies and carbohydrate epitopes reactive with sera from histoplasmosis patients. It is very important that sensitive chemiluminescence immunoassays be used with purified antigenic molecules to ensure specificity for the diagnosis and follow-up of parasitic and fungal infections. © 1994 Wiley-Liss, Inc.