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Non-melanoma skin cancer is the most common malignancy that shows increasing incidence due to our cumulative exposure to ultraviolet irradiation. Its major subtypes, basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) differ in pathobiology, phenotype and clinical behavior, which must be reflected at the molecular level. In this study, protein expression profiles of BCC and SCC were tested in tissue microarrays and correlated with that of actinic keratosis, Bowen's disease, seborrheic keratosis and normal epidermis by detecting 22 proteins involved in cell interactions, growth, cell cycle regulation or apoptosis. The significantly more reduced collagen XVII, CD44v6, pan-Desmoglein levels and more evident E-Cadherin delocalization in BCC compared to SCC correlated with the de novo dermal invasion of BCC against the progressive invasion from in situ lesions in SCC development. EGFR was also expressed at a significantly higher level in SCC than in BCC. The upregulated cell communication protein connexin43 in BCC could contribute to the protection of BCC from metastatic invasion. Elevated cell replication in BCC was underlined by the increased topoisomerase IIα and reduced p21(waf1) and p27(kip1) positive cells fractions compared to SCC. Compared to differentiated keratinocytes, caspase-8 and -9 were equally upregulated in skin carcinoma subtypes for either mediating apoptosis induction or immune escape of tumor cells. Hierarchical cluster analysis grouped SCC and actinic keratosis cases exclusively together in support of their common origin and malignant phenotype. BCC cases were also clustered fully together. Differentially expressed proteins reflect the distinct pathobiology of skin carcinoma subtypes and can serve as surrogate markers in doubtful cases.

Collagen XVII/BP180, a hemidesmosomal adhesion protein, is lost during normal keratinocyte maturation; however, it may be reexpressed upon malignant transformation. In this work, highly sensitive monoclonal antibodies 6D1 and 9G2 were produced, characterized, and used for the detection of collagen XVII in a tissue microarray series of archived samples of nonmelanocytic epithelial neoplasias, including 5 verruca vulgaris, 14 seborrheic keratosis, 38 actinic keratosis, 38 basal cell carcinoma (BCC), 15 basosquamous carcinoma, 58 squamous cell carcinoma (SCC), and 9 normal skin. Digital microscopy and a new tissue microarray software linking image and patient data allowed easy and validated evaluation and quality archiving of stained samples. In normal skin and benign epidermal lesions, collagen XVII protein was restricted to basal keratinocytes. However, possibly as a sign of undifferentiated/transformed state, it was widely expressed in SCC showing elevated levels around invasive tumor fronts with some staining in tumor adjacent stroma, endothelium, and histiocytes. Collagen XVII immunostaining of atypical keratinocytes in most actinic/solar keratosis supports the view of their malignancy and common origin with SCC. Squamous component of basosquamous carcinoma showed moderate reaction, whereas islets of BCC were mainly negative reflecting the diverse genotype and phenotype, and pathogenesis of SCC and BCC. These results suggest that collagen XVII neoexpression may be associated with early atypia/malignant transformation of keratinocytes. Further investigations are under way to analyze the potential of these antibodies for tracing progression and metastatic potential of skin tumors.

A significant pathogenetic role of antimuscarinic acetylcholine receptor-3 (anti-m3AChR) autoantibodies in primary Sjögren's syndrome (pSS) has been suggested. However, the binding of these antibodies to the receptors in the target tissues has not yet been demonstrated. In this study, the binding characteristics of pSS sera and anti-m3AChR-monospecific sera affinity-purified from pSS patients to labial salivary gland samples from healthy subjects were studied with light- and electron microscopy. Furthermore, the ultrastructural localisation of in vivo deposited antibodies in pSS salivary glands was also investigated. Light microscopic immunohistochemistry revealed the binding of the anti-m3AChR-specific sera to the membrane of acinar cells. Similar reaction end-products were observed in the pSS salivary gland epithelial cell membranes. With electron microscopy, the autoantibody binding was observed to be localised to the junctions of epithelial cell membranes with nerve endings, both in normal and pSS glands. The results indicate that anti-m3AChR antibodies bind to the receptors in the salivary glands.

Although the pathogenetic significance of hepatitis B virus x protein (HBxAg) in chronic hepatitis, liver cirrhosis, and primary hepatocellular carcinoma has already been studied, the comparative analyses of both the actual serum HBxAg levels and antibody production against various HBx epitopes have been examined to lesser extent. We have simultaneously investigated the relationship between antibody production (IgG and IgM) against the HBxAg fragments and HBxAg level in the sera of patients with acute (14) or chronic hepatitis (80) and symptomless carriers (12). A recently developed sandwich-type ELISA was used for the quantitative measurements of HBxAg. Overlapping recombinant and synthetic antigens were used to map the fine epitope specificities of circulating anti-HBx antibodies. In acute hepatitis, we have found high and homogenous correlation in the IgM type immune responses against all the examined HBxAg regions. Moreover, strong correlation has been observed between IgG type immune responses to a characteristic C-terminal region (C1: 79-117) and the longest fragment (X: 10-143). Moderate correlation has been found between HBxAg concentration and the IgG type anti-HBx antibody levels against C-terminus of HBxAg in patients with chronic hepatitis. In the case of symptomless carriers, there were also demonstrable associations in the immune responses against the C-terminal sequences; however, significant correlations were found for antibody production against the N-terminal region as well. The examinations show that the C-terminal sequence, responsible for transactivation, promotes an efficient IgG antibody response in all three groups of patients, whereas the negative regulator N-terminal part of the HBxAg molecule for the most part does not trigger antibody production. This suggests that the immune responses against various - biologically active - epitopes of the HBxAg may have a different role in the pathogenesis of hepatitis and may be used as prognostic markers in human HBV infections.

The hepatitis B virus X protein (HBxAg) is responsible for severe complications of HBV infections including primary hepatocellular carcinoma. A sandwich type ELISA and a flow cytometric microbead assay for quantitative determination of serum levels of Hbx-Ag are introduced. We have previously developed monoclonal antibody families against well-conserved epitopes on HbxAg, characterized by different immunohistochemical and immunoserological techniques. Special selection of the antibody pairs provided highly sensitive and highly specific tools for quantitative immunoassay development. The resulting assays were tested on human sera (208 samples) collected from patients suffering from different clinical forms of HBV infection. The sensitivity range of the sandwich type ELISA was between 4 and 2000 ng/ml as measured on both the recombinant antigen and the sera of chronic hepatitis patients. A further flow cytometric microbead assay was established and tested in parallel with the ELISA. The quantitative results of these two immunoserological techniques were in strong correlation and they were found to be highly specific and sensitive on clinical samples. The HBxAg ELISA technique is applicable for routine clinical laboratory measurements, and our HBxAg microbead technique is recommended for complex multiparametric measurements combined with other markers.

Bullous pemphigoid (BP) is characterized immunologically by tissue-bound and circulating autoantibodies targeting the hemidesmosomal proteins BP230 and BP180. Recent evidence suggests a pathophysiological role for autoantibodies against alpha6 integrin in the subepidermal blister formation of oral pemphigoid. The objective of our study was to investigate the presence of anti-alpha6 integrin antibodies in patients with classical BP. The autoantibody profiles of 30 patients with BP, 10 patients with pemphigus vulgaris, and 20 healthy persons were identified. With the use of PeptideStructure and PlotStructure software, four different antigenic epitopes for alpha6 integrin were predicted, and their fusion recombinant constructs were prepared in an E. coli expression system. Sera were tested for alpha6 integrin autoantibodies by an ELISA technique. Altogether, 52% of the patients with BP displayed circulating antibodies against at least one recombinant protein. Our findings provide the first evidence for the presence of anti-alpha6 integrin antibodies in patients with classical BP.

Bullous pemphigoid (BP) is an IgG-mediated autoimmune blistering disease that targets the hemidesmosomal proteins BP230 and BP180. To investigate the pathogenic role of anti-BP230 antibodies, rabbit polyclonal antibodies were generated against an antigenic sequence of the human BP230 antigen (BPAG 1, 2479-2499), which shows 67% homology in the human and the mouse BP230. Purified IgG from the rabbit anti-serum was transferred subcutaneously into the dorsal skin of neonatal isogeneic CBA/Ca (CBA) mice in a dose of 5 mg (n=7) or 1.2 mg IgG/50 microl (n=16). After 24 h, 1 of the mice injected with 5 mg IgG exhibited blisters, but the dorsal skin of all 7 of them was erythematous, and gentle friction produced a fine persistent wrinkling of the epidermis in 4 mice. The mice injected with 1.2 mg IgG developed less severe symptoms. Immunohistological examinations revealed linear rabbit IgG and mouse C3 depositions along the basement membrane of the perilesional skin and subepidermal blister formation. An intradermal inflammatory reaction (granulocyte infiltration) was also detected. None of these symptoms was seen in mice injected with IgG from a control rabbit anti-serum. These findings demonstrate that antibodies against BP230 can elicit the clinical and immunopathological features of BP in neonatal mice, suggesting that anti-BP230 antibodies may possibly play a pathogenic role in this disease.

To evaluate the antigenicity of a peptide representing a part of the second extracellular loop of the human muscarinic acetylcholine receptor 3 (m3AChR) with autoimmune sera from primary Sjogren's syndrome (pSS), enzyme-linked immunosorbent assays (ELISAs) were developed. On the basis of the computer-predicted data, a 16-mer synthetic peptide KRTVPPGECFIQFLSE (KRSE213-228) was produced by solid-phase peptide synthesis. cDNA coding for the KRSE peptide was chemically synthetized and utilized to express the recombinant glutathione S-transferase (GST)-KRSE fusion protein. The immunoreactivities of the two antigens were tested in ELISAs with the sera of 40 pSS patients and 40 healthy controls. The specificity of the reaction was confirmed by inhibition assays and immunoblottings. The pSS sera resulted in significantly higher mean optical densities than those of the healthy controls (KRSE: 0.4149 vs 0.1494, p<0.0001; GST-KRSE 0.4765 vs 0.1764, p<0.0001). The immunological recognition with the recombinant fusion antigen was significantly better than that for the free peptide (p=0.0068). The sensitivities of the assays were 77.5% (KRSE) and 97% (GST-KRSE). The results of the concentration-dependent inhibition assays by the two systems of peptide presentation indicated that the KRSE sequence is specific for pSS sera. This is the first demonstration of the antigenicity of a novel peptide fragment of the human m3AChR in pSS. The analysed peptide could be of diagnostic relevance.

The serum level of autoantibodies against autoantigens of the bullous pemphigoid peptides 1 and 2 (BPAG1 and BPAG2) is a relevant diagnostic marker. Twelve representative sera of BP were tested against the RSILPYGDSMDRIEKDRLQMAP amino acid sequence that is an epitope fragment of the NC16A domain of BPAG2 (AC Q02802; 507-528) to find the most suitable antigenic form for specific detection of autoantibodies of BP patients' sera by quantitative ELISA system. The antigenic epitope sequence was presented as an antigen in a carrier free form of dimeric peptide (BP22), dimeric peptide fused to glutathione S-transferase (GST-BP22) or dimeric peptide chemically conjugated to polyLys(Ser-DL-Alam) (SAK-BP22). The intensity of ELISA reaction was highest against the recombinant fusion antigen GSTBP22; the chemically conjugated SAK-BP22 performed less well than the free dimeric form of the peptide. In the case of the GST-BP22 antigen, the (GST-BP22)-(GST)492nm optical density values were determined. There was no significant difference between the mean ODs of the GST-BP22 and the SAK-BP22 (0.888 vs. 0.892, p= 0.9726). Conjugating the epitope peptide with the synthetic carrier SAK was advantageous, as it abrogated cross-reactivity with GST carrier protein. Consequently, the SAKBP22 conjugate appears to be the most reliable assay component, avoiding cross-reactivity with GST and simplifying the detection and evaluation of BP autoantibodies in routine ELISA diagnostic system.

The recombinant form of the 17kDa, highly hydrophobic and disulfide-bonded hepatitis B virus X protein (HBX) was used for developing a set of monoclonal antibodies (Mab). Our present goal was to determine the fine epitope specificity of our anti-HBX Mab. Based on computer analysis two sequences (amino acids 22-31 and 100-114) were predicted for possessing high immunogenity while the anti-HBX Mab did not recognized them. Limited proteolysis and mass spectroscopic analysis suggested another possible sequence (amino acids 14-26), which also proved to be negative using an immunoserological test. Subsequently, we performed a screen of a phage displayed random peptide library, by which we could localize the epitope to amino acids 88-93. This finding was confirmed using three overlapping fusion peptides spanning amino acids 77-142. Their testing in ELISA assigned the epitope to amino acids 77-95, which supports the result obtained by screening the phage displayed library. Our results suggest the necessity of a complex application of current molecular biological and immunological techniques in fine structure mapping. This approach will be useful to study the prognostic relevance of different antigenic sites on HBX during the development of chronic hepatitis and primary hepatocellular carcinoma.

Recombinant epitopic peptides BP1 and BP2 representing the Bullous pemphigoid autoantigens of BP230 and BP180 bound to the fusion partner glutathione-S-transferase (pGEX-4T-2, Pharmacia) have been previously shown to increase the efficacy of diagnosis of the disease. Using glutathione-S-transferase-bound monomer peptides, the sensitivity of the immunological reaction exceeded that of the free synthetic epitopes and was further increased with the number of epitopic blocks in the multimer fusion products. This has been explained by the avidity effect of the fusion partner dimer formation and the high ligand affinity due to the tandem repetitions of epitopic sequences. However, a beneficial conformation of the bound epitopic peptides might also contribute to the above phenomenon. Circular dichroism (CD) and Fourier transform infrared (FTIR) absorption spectroscopic studies revealed the importance of glutathione-S-transferase to induce and stabilize ordered secondary structures of the epitopic peptides. The free monomer and multimer peptides in aqueous buffer were present as a mixture of unordered and beta-sheet conformation, while binding them to the fusion partner the proportion of ordered secondary structures increased in parallel with the number of antigenic epitopes. The most prominent changes in the conformational state of the monomers in the fusion form were the increase of alpha-helical and beta-sheet and the decrease of unordered conformation, while in the case of oligomeric peptides the adoption of a helical conformation was accompanied by the decrease of beta-sheet structure. An outstanding alpha-helix content (46%) was detected in the case of the trimeric BP1 in its recombinant fusion form.

In an earlier study, the circulating autoantibodies in patients with bullous pemphigoid (BP) were demonstrated in higher frequencies by means of an immunoblot technique then via indirect immunofluorescence. In the present work with the help of Peptide Structure software, two matched antigenic epitopes were chosen and synthesized. The sera of 34 patients with BP were investigated in parallel by an immunoblot technique using a human epidermal extract, and by an ELISA technique with synthetic peptides. The sera of 16 healthy persons and 10 patients with other bullous diseases served as controls. Among the 34 patients with BP, 23 sera proved positive for at least one synthetic peptide. Positive reactions with the major BP antigen (230 kD) were found in 22 patients by immunoblot technique and in 16 patients by the ELISA technique with the synthetic peptide, whereas with the minor BP antigen (180 kD), positive reactions were found in 9 patients by the immunoblot technique and 18 patients by the ELISA technique using the synthetic antigenic epitope of the minor BP antigen. All control sera were negative for both antigens in ELISA investigations. In 3 patients with pemphigus vulgaris, characteristic bands against pemphigus vulgaris antigen were identified by means of the immunoblot technique, but all other cases were negative. It is suggested that the development of this technique may lead to an opportunity for the rapid and simple diagnosis of BP.

The carboxy-terminal domain of polymerase gene of Rous sarcoma virus was cloned into an expression vector under the control of lac regulatory elements, resulting in the plasmid pMF1413. Upon isopropyl-beta-D-thiogalactopyranoside induction, viral integration (IN) protein was expressed in large quantity in Escherichia coli. The expressed recombinant protein was prepurified by successive washing of the bacterial pellet with 0.1 M NaCl and detergents. Further purification was performed in high yield by standard chromatography methods. The purified enzyme revealed selective DNA cleaving activity on supercoiled plasmid with the LTR-LTR junction fragment. The reaction was metal ion dependent, with a preference for Mn2+ over Mg2+, and showed substrate specificity at 1 mM MnCl2.

The characteristics of primary Sjögren's syndrome are described on the basis of the follow-up of 65 patients with extraglandular symptoms at the onset and during the disease. The mean age of the patients at onset was 41.8 years and at the time of definite diagnosis was 45.8 years. Articular (32 cases), lacrimal (30 cases) and salivary (30 cases) manifestations were the most frequent initial symptoms. In only 22 of the 65 patients could Sjögren's syndrome be diagnosed at the onset. In most cases, the articular symptoms observed observed in 56 patients during the course corresponded to true polyarthritis, as verified by joint scintigraphy. Most frequently the wrists and ankles were affected. Chronic atrophic gastritis was found in 35 patients. In the young patients (13 cases), both the antrum and the corpus were affected more frequently than in the controls. In middle-aged patients (21 cases), atrophy of the antrum, and in the elderly (10 cases) atrophy of the corpus was more frequent than in the controls. All three types of chronic atrophic gastritis occurred in the disease. The decreased gastric acid secretion was characteristic of types A and AB gastritis, but the hypergastrinaemia only of type A. It was verified that chronic duodenitis and jejunitis occur in the disease. The pancreatic lesions were mild. Renal involvement was detected in 15 patients, vascular symptoms in 22 and lower-airway changes in 21. The variety of the different symptoms proved that primary Sjögren's syndrome can involve many organs.

Fractionation on sucrose gradients of nuclear described extracts prepared from cultured Drosophila melanogaster cells by sonication of the nuclei in the presence of rat liver cytosol RNAase inhibitor revealed a complex polysome-like pattern of nuclear ribonucleoprotein complexes. The bulk of these heterogeneous ribonucleoprotein (hnRNP) complexes sedimented in the 30S to 80S zone of the sucrose gradient. According to biochemical and morphological data, the monomer particle proved to be the 45S hnRNP and its average diameter was found by electron microscopy to be 24-26 nm. The buoyant density of both the mono and polyparticles was about 1.4 g/cm3, with a slight degree of heterogeneity. The proteins from different zones of the sucrose gradient were composed primarily of similar polypeptides of 47 000, 56 000, 64 000, 96 000 and 130 000 daltons. Complete dissociation of nuclear hnRNP complexes was observed by resedimentation of the particles in the presence of 0.7 M NaCl or 4 M urea. RNAase A digestion (0.1 microgram/ml at 0 degree C for 10 min) resulted in the solubilization of part of the hnRNP and aggregation of some particles. The bulk of the RNA isolated from the different sized hnRNP complexes sedimented in the 7 to 11S region in the sucrose gradient. The large hnRNP complexes contained hnRNA strands larger than 15S, up to 28S. The base composition of the RNA from the 45S monoparticles proved to be AU type: A + U/G + C = 1.7. The RNAs from the 60-75S and 90- 100S polyparticles were also AU type, with an A + U/G + C ratio of 1.46 and 1.21, respectively. The hnRNP complexes exhibited marked heterogeneity in the electron microscope. Our biochemical and morphological observation point to a nonrandom organization of hnRNP particles in Drosophila melanogaster nuclei.