The plasma gelsolin levels in atopic dermatitis: Effect of atopy ad disease severity

BACKGROUND: Gelsolin is an actin-binding protein with several cellular functions including anti-apoptosis and is reported to have an anti-inflammatory effect. Apoptosis of keratinocytes has been implicated as a key mechanism of atopic dermatitis (AD). OBJECTIVE: We aimed to determine plasma gelsolin (pGSN) levels in children with atopic dermatitis (AD). METHOD: The diagnosis of AD was made according to Hanifin and Rajka criteria. The disease severity was scored by objective SCORAD index by the same allergist. Skin prick testing (SPT), total IgE levels, and eosinophil counts were analyzed. The pGSN levels were determined using ELISA technique. RESULTS: Children aged between 0.5 and 3.0 years were included in the study. The children with AD (AD; n = 84) were analyzed in two groups according to the presence (AD+/Atopy+; n = 54) or absence of SPT positivity (AD+/Atopy−; n = 30). The comparisons were made with a healthy control group matched for age and sex (n = 81). The median (interquartile range) of pGSN levels in AD+/A+, AD+/A− and control groups were 267 μg/ml (236-368), 293 (240-498) and 547 (361-695), respectively (p < 0.001). The difference between the control group and AD sub-groups remained significant after Bonferroni correction (p < 0.001). Correlation analysis failed to reach significance with the disease severity total IgE levels and eosinophil counts. CONCLUSION: This is the first study investigating the association of pGSN levels with AD and disease severity. pGSN levels decreased in AD. These findings suggest that gelsolin may have a role in the disease process in AD patients

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Preparation of novel monoclonal antibodies against chelated cadmium ions.

The detection of cadmium ions using enzyme-linked immunosorbent assays (ELISA) has been reported by several research groups. Because cadmium ions are too small to stimulate the immune system, high molecular weight immunogens of cadmium are constructed using bifunctional chelators. At present, the most commonly used bifunctional chelator for the preparation of antigens for heavy metal ions is 1-(4-isothiocyanobenzyl) ethylenediamine N,N,N',N'-tetraacetic acid (ITCBE). However, the price of ITCBE is high. So we are interested in a cheaper bifunctional chelator, 1-(4-aminobenzyl) ethylenediamine N,N,N',N'-tetraacetic acid (aminobenzyl-EDTA). Here, cadmium ions were conjugated to carrier proteins using aminobenzyl-EDTA to make artificial antigens. Then, several mice were immunized with the antigen. And monoclonal antibodies (MAbs) against cadmium were produced. Spleen cells of immunized mice were fused with myeloma cells. The resulting hybridomas were screened using protein conjugates which were covalently bound to metal-free EDTA or cadmium. Three hybridoma cell lines (A3, E4 and B5) that produced MAbs with high selectivity and sensitivity were expanded for further study. Cross-reactivities with other metals were below 1 %. These antibodies were used to construct competitive ELISAs. The IC50 for A3 was 8.4 µg/l. The detection range and the lowest detection limit using the antibody A3 was 0.394-64.39 and 0.051 µg/l, respectively. Spike-recovery studies in tap water showed that the antibody A3 could be used for cadmium detection in drinking water.

Colloidal gold nanoparticle probe-based immunochromatographic assay for the rapid detection of chromium ions in water and serum samples.

An immunochromatographic assay (ICA) using gold nanoparticles coated with monoclonal antibody (McAb) for the detection of chromium ions (Cr) in water and serum samples was developed, optimized and validated. Gold nanoparticles coated with affinity-purified monoclonal antibodies against isothiocyanobenzyl-EDTA (iEDTA)-chelated Cr(3+) were used as the detecting reagent in this completive immunoassay-based one-step test strip. The ICA was investigated to measure chromium speciation (Cr(3+) and Cr(6+) ions) in water samples. Chromium standard samples of 0-80 ng mL(-1) in water were determined by the test strips. The results showed that the visual lowest detection limit (LDL) of the test strip was 50.0 ng mL(-1). A portable colorimetric lateral flow reader was used for the quantification of Cr. The results indicated that the linear range of the ICA with colorimetric detection was 5-80 ng mL(-1). The ICA was also validated for the detection of chromium ions in serum samples. The test trips showed high stability in that they could be stored at 37°C for at least 12 weeks without significant loss of activity. The test strip also showed good selectivity for Cr detection with negligible interference from other heavy metals. Because of its low cost and short testing time (within 5 min), the test strip is especially suitable for on-site large-scale screening of Cr-polluted water samples, biomonitoring of Cr exposure, and many other field applications.

A useful method for the detection of ethylenediaminetetraacetic acid- and cold agglutinin-dependent pseudothrombocytopenia.

INTRODUCTION: Pseudothrombocytopenia (PTCP), caused by platelet (PLT) aggregation, is usually associated with ethylenediaminetetraacetic acid (EDTA)-dependent antibodies and cold aggluti-nins against PLT antigens. The aim of this study was to identify the PTCP and discover the most practical method to distinguish it from real thrombocytopenia. METHODS: This study included 85 patients without hemorrhagic abnormalities and suspected PTCP. Blood samples containing EDTA, citrate and EDTA-kanamycin (KN) were analyzed at room temperature and 37°C. RESULTS: PTCP was detected in 24 of 85 patients. In 23 of 24 patients, EDTA-dependent pseudothrombocytopenia (EDTA-PTCP) was detected; 5 of whom had also the cold agglutinin-dependent PTCP. In only 1 of 24 patients, the cold agglu-tinin-dependent PTCP was found. In this study, no significant difference was observed in leukocyte counts comparing EDTA and citrate blood samples in cases with EDTA-PTCP. CONCLUSION: In clinical laboratories, a significant portion of the cases with low PLT counts was attributable to EDTA-PTCP and, therefore, did not require treatment. Even if these cases can be detected by bringing the blood samples containing EDTA to 37°C or by adding KN to blood samples containing EDTA, the use of blood samples containing citrate taken for erythrocyte sedimentation rate analysis is a more practical priority method.

Immunochromatography for the rapid determination of cadmium concentrations in wheat grain and eggplant.

BACKGROUND: A simple and quick on-site test for trace levels of cadmium (Cd) in food is needed because of the human toxicity of this heavy metal. We developed an immunochromatography kit which uses the antigen-antibody complex reaction between the Cd-ethylenediaminetetraacetic acid (Cd-EDTA) complex and an anti-Cd-EDTA antibody. We previously reported the successful use of this kit to determine Cd concentrations in brown rice with respect to the international standard: 0.4 mg kg⁻¹. Here, we measured, using this immunochromatography kit, Cd concentrations in crops with lower international standards than rice. RESULTS: Cadmium extracted with 0.1 mol L⁻¹ HCl from wheat grain and fresh eggplant was purified sufficiently using an ion-exchange column treatment. Appropriate HCl extraction rates and dilution rates for the column eluate were selected; Cd concentrations in wheat grain and fresh eggplant were determined successfully by immunochromatography with respect to the international standards of 0.2 mg kg⁻¹ and 0.05 mg kg⁻¹ fresh weight, respectively. CONCLUSION: Approximate Cd concentrations in wheat grain and fresh eggplant can be monitored easily and quickly by this method at locations where facilities for acid digestion and precision analysis are not available.

Evaluation of inflammatory response of EDTA, EDTA-T, and citric acid in animal model.

INTRODUCTION: The biocompatibility of chelating agents and organic acids have been explained by a variety of methods, and suggestions for use have been based more on clinical observations and physicochemical properties than on biological aspects. The present study aimed to evaluate the inflammatory response of 17% EDTA, 17% EDTA-T, and 10% citric acid in bony defect created in rat jaws. METHODS: Mandibular through and through critical size defects were created bilaterally in 60 rats. Fibrinol (Baldacchi SA, São Paulo, Brazil), a cube-shaped compound of absorbable bovine fibrin foam and sodium chloride, was used as a carrier of the substances. One side had received Fibrinol (control), whereas the opposite side had received Fibrinol soaked with each substance on the 1st, on the 7th, on the 14th, and on the 28th day (n=5 for each day). Hemijaws were prepared for light microscopy, and samples were stained with hematoxylin and eosin. Digitized images were analyzed with a morphometric software (ImageJ; National Institute of Mental Health, Bethesda, MD). to obtain the number of inflammatory cells per area. Comparisons were performed by using the Kruskal-Wallis test (p=0.05). RESULTS: For all days, 10% citric acid and 17% EDTA-T showed, respectively, the lowest and highest number of inflammatory cells per area. All tested substances and controls showed the highest inflammatory cell response on the 14th day. CONCLUSION: Among the tested substances, 10% citric acid proved to be the less aggressive tested solution at 14 days. At 28 days, all solutions were similar, but EDTA-T kept showing the higher number of inflammatory cells.

Intranasal administration of proteoliposome-derived cochleates from Vibrio cholerae O1 induce mucosal and systemic immune responses in mice.

Conservative estimates place the death toll from cholera at more than 100,000 persons each year. A particulate mucosal vaccine strategy combining antigens and immune stimulator molecules from Vibrio cholerae to overcome this problem is described. Proteoliposomes extracted from V. cholerae O1 were transformed into cochleates (AFCo2, Adjuvant Finlay cochleate 2) through a calcium inducible rotary dialysis method. Light microscopy was carried out and tubules of 16.25+/-4.57 microm in length were observed. Western blots were performed to verify the immunochemical properties of the main AFCo2 incorporated antigens, revealing full recognition of the outer membrane protein U (OmpU), lipopolysaccharide (LPS), and mannose-sensitive hemagglutinin (MSHA) antigens. AFCo2 were administered by the intranasal route using a two or three dose schedule and the immune response against V. cholerae antigens was assessed. Three AFCo2 doses were required to induce significant (p<0.05), antigen specific IgA in saliva (1.34+/-0.135) and feces (0.60+/-0.089). While, two or three doses of AFCo2 or proteoliposomes induce similar specific IgG and vibriocidal activity responses in sera. These results show for the first time that AFCo2 can be obtained from V. cholerae O1 proteoliposomes and have the potential to protect against the pathogen when administered intranasally.

Mucosal immunization using proteoliposome and cochleate structures from Neisseria meningitidis serogroup B induce mucosal and systemic responses.

Most pathogens either invade the body or establish infection in mucosal tissues and represent an enormous challenge for vaccine development by the absence of good mucosal adjuvants. A proteoliposome-derived adjuvant from Neisseria meningitidis serogroup B (AFPL1, Adjuvant Finlay Proteoliposome 1) and its derived cochleate form (Co, AFCo1) contain multiple pathogen-associated molecular patterns as immunopotentiators, and can also serve as delivery systems to elicit a Th1-type immune response. The present studies demonstrate the ability of AFPL1and AFCo1 to induce mucosal and systemic immune responses by different mucosal immunizations routes and significant adjuvant activity for antibody responses of both structures: a microparticle and a nanoparticle with a heterologous antigen. Therefore, we used female mice immunized by intragastric, intravaginal, intranasal or intramuscular routes with both structures alone or incorporated with ovalbumin (OVA). High levels of specific IgG antibody were detected in all sera and in vaginal washes, but specific IgA antibody in external secretions was only detected in mucosally immunized mice. Furthermore, antigen specific IgG1 and IgG2a isotypes were all induced. AFPL1 and AFCo1 are capable of inducing IFN-gamma responses, and chemokine secretions, like MIP-1alpha and MIP-1beta. However, AFCo1 is a better alternative to induce immune responses at mucosal level. Even when we use a heterologous antigen, the AFCo1 response was better than with AFPL1 in inducing mucosal and systemic immune responses. These results support the use of AFCo1 as a potent Th1 inducing adjuvant particularly suitable for mucosal immunization.

Monoclonal Antibodies 1G12 and 6A12 to the N-domain of human angiotensin-converting enzyme: fine epitope mapping and antibody-based detection of ACE inhibitors in human blood.

Angiotensin I-converting enzyme (ACE), a key enzyme in cardiovascular pathophysiology, consists of two homologous domains (N- and C-), each bearing a Zn-dependent active site. ACE inhibitors are among the most prescribed drugs in the treatment of hypertension and cardiac failure. Fine epitope mapping of two monoclonal antibodies (mAb), 1G12 and 6A12, against the N-domain of human ACE, was developed using the N-domain 3D-structure and 21 single and double N-domain mutants. The binding of both mAbs to their epitopes on the N-domain of ACE is significantly diminished by the presence of the C-domain in the two-domain somatic tissue ACE and further diminished by the presence of sialic acid residues on the surface of blood ACE. The binding of these mAbs to blood ACE, however, increased dramatically (5-10-fold) in the presence of ACE inhibitors or EDTA, whereas the effect of these compounds on the binding of the mAbs to somatic tissue ACE was less pronounced and even less for truncated N-domain. This implies that the binding of ACE inhibitors or removal of Zn2+ from ACE active centers causes conformational adjustments in the mutual arrangement of N- and C-domains in the two-domain ACE molecule. As a result, the regions of the epitopes for mAb 1G12 and 6A12 on the N-domain, shielded in somatic ACE by the C-domain globule and additionally shielded in blood ACE by sialic acid residues in the oligosaccharide chains localized on Asn289 and Asn416, become unmasked. Therefore, we demonstrated a possibility to employ these mAbs (1G12 or 6A12) for detection and quantification of the presence of ACE inhibitors in human blood. This method should find wide application in monitoring clinical trials with ACE inhibitors as well as in the development of the approach for personalized medicine by these effective drugs.

Validation of accuracy of enzyme-linked immunosorbent assay in hybridoma screening and proposal of an improved screening method.

The 96-well plate format of enzyme-linked immunosorbent assay (ELISA) is the de facto standard in screening hybridomas for active antibody. Despite its widespread use, there have been few or no systematic attempts to validate its accuracy and answer the fundamental question, is it finding all the positives? We report here on a comparison between ELISA and a semiautomated flow-based kinetic exclusion assay (KinExA), both used in screening the same hybridoma cell line. Our finding is that ELISA is both overreporting (false positives) and underreporting (false negatives) compared to the KinExA system. The large number of hybridoma cells (e.g., cultured in six 96-well plates) that must be checked is daunting in considering any method other than ELISA for routine screening. To overcome this, we devised a sampling strategy in which wells are combined in a specified pattern, allowing a significant reduction in the total number of measurements required.

Identification of important residues in metal-chelate recognition by monoclonal antibodies.

The molecular characterization of antibodies directed against metal-chelate complexes will provide important insights into the design and development of radiotherapeutic and radioimaging reagents. In this study, two monoclonal antibodies directed against different metal-chelate complexes were expressed as recombinant Fab fragments. Covalent modification and site-directed mutagenesis were employed to ascertain those residues important in antigen recognition. Antibody 5B2 was raised to a Pb(II)-loaded isothiocyanatobenzyl-diethylenetriamine pentaacetic acid (DTPA)-protein conjugate. The native antibody bound to complexes of Pb(II)-p-aminobenzyl-DTPA with an affinity of 4.6 x 10(-9) M. A monovalent Fab fragment prepared from the native protein and a bivalent recombinant fragment exhibited comparable affinities for the same Pb(II)-chelate complex, approximately 6-fold lower than that of the intact antibody. Covalent modification and molecular modeling predicted that Lys(58) in the heavy chain contacted the Pb(II)-chelate ligand. Mutational analysis supported a role for Lys(58) in ion pair or hydrogen bond formation with the carboxylate groups on the chelate. Antibody E5 was directed toward an isothiocyanatobenzyl-ethylenediamine tetraacetic acid (EDTA)-protein conjugate loaded with ionic Cd(II). The native immunoglobulin recognized Cd(II)-p-aminobenzyl-EDTA with an affinity of 8.2 x 10(-12) M. A proteolytically derived fragment and a bivalent recombinant fragment bound to the same Cd(II)-chelate complex with affinities that were comparable to that of the native antibody. Homology modeling and mutagenesis identified three residues (Trp(52) and His(96) in the heavy chain and Arg(96) in the light chain) that were important for Cd(II)-chelate recognition. His(96) likely mediates a direct ligation to the Cd(II) ion and Trp(52) appears to be involved in hydrophobic stacking with the benzyl moiety of the chelator. Arg(96) appeared to mediate an electrostatic or hydrogen bond to the chelate portion of the complex. These studies demonstrate that antibody recognition of metal-chelate haptens occurs through a limited number of molecular contacts and that these molecular interactions involve both direct ligation between the antibody and the metal ion and interactions between the antibody and the chelator.

Monoclonal antibodies that recognize minimal differences in the three-dimensional structures of metal-chelate complexes.

Immunization of BALB/c mice with a cadmium-chelate-protein conjugate resulted in the isolation of two hybridoma cell lines (A4 and E5) that synthesized antibodies with different variable regions, but similar metal-chelate affinity. The ability of these two monoclonal antibodies to interact with 12 different metal-chelate complexes was studied using the KinExA 3000 immunoassay instrument. The two antibodies showed the highest affinity for cadmium and mercury complexes of ethylenediamine N,N,N',N'-tetraacetic acid (EDTA). The E5 antibody bound to EDTA complexes of cadmium and mercury with equilibrium dissociation constants (K(d)) of 1.62 x 10(-)(9) M and 3.64 x 10(-)(9) M, respectively. The corresponding values for the A4 antibody were 14.7 x 10(-)(9) M and 3.56 x 10(-)(9) M. Addition of a cyclohexyl ring to the EDTA backbone increased the affinity of E5 for the metal-chelate haptens, while decreasing the binding of A4 to the same haptens. Based on available crystal structures, molecular models were constructed for five different divalent metal-chelate complexes. The models were compared to determine structural features of the haptens that may influence antibody recognition. Difference distance matrixes were used to identify areas of the metal-chelate haptens that differed in three-dimensional space. Antibody affinity correlated well with the extent of total structural difference for these metal-EDTA complexes.

Internal defenses of the snail Biomphalaria glabrata.

Injection of foreign particles (zymosan, latex beads, living bacteria) and substances (ferritine, horseradish peroxidase) in Biomphalaria glabrata induces the rapid appearance of tubular double-helical filaments in the hemolymph. This rapid induction may be due to the polymerization of precursor proteins of the hemolymph. Tubular helical filaments are also observed in normal snails, especially in the hemal spaces of the proximal kidney; they seem to belong to the extracellular matrix and form bundles of a few parallel units associated with fine fibrils. Hemocytes adhere to these bundles by means of the filopodia tip or by small areas of the cell surface; consequently, they may become temporarily sedentary in the hemal spaces. The deposition of helical filaments seems increased in ageing snails and in snails parasitized by Echinostoma caproni.

Cell binding sequences in mouse laminin alpha1 chain.

Laminin-1, a multifunctional glycoprotein of the basement membrane, consists of three different subunits, alpha1, beta1, and gamma1 chains. Previously, we used synthetic peptides to screen for biologically active sequences in the laminin alpha1 chain C-terminal globular domain (G domain) and identified several cell binding sequences (Nomizu, M., Kim, W. H., Yamamura, K., Utani, A., Song, S. Y., Otaka, A., Roller, P. P., Kleinman, H. K., and Yamada, Y. (1995) J. Biol. Chem. 270, 20583-20590). Here, we identify new cell binding sequences on the remainder of the laminin alpha1 chain by systematic peptide screening, using 208 overlapping synthetic peptides encompassing the central and N-terminal portions of the alpha1 chain. HT-1080 cell attachment activity to the peptides was evaluated using peptide-coated plastic substrates and peptide-conjugated Sepharose beads. Twenty five peptides showed cell attachment activities on either the peptide-coated plastic substrates and/or the peptide-conjugated Sepharose beads. A-13 (RQVFQVAYIIIKA) showed strongest cell attachment activity in both the assays. Cell attachment to 14 of the peptides was inhibited by heparin. EDTA and integrin antibodies inhibited cell adhesion to two of the peptides, A-13 and A-25, suggesting that these sites likely bind to integrins. These peptides inhibited cell attachment to laminin-1 but not to collagen I, suggesting these active sites are available on the intact molecule. Most of active sequences were localized on globular domains suggesting that these structures play a critical role in binding to cell-surface receptors.

Establishment and characterization of monoclonal antibodies against an octahedral gallium chelate suitable for immunoscintigraphy with PET.

As a prerequisite for preparing bispecific antibody conjugates containing anti-tumor and anti-metal chelate binding sites that can be used for pretargeted immunoscintigraphy, monoclonal antibodies (Mabs) have been raised against an octahedral metal chelate synthetized from gallium (Ga) and the hexadentate ligand N,N'bis[2-hydroxy 5-(ethylene beta carboxy) benzyl] ethylenediamine N,N' diacetic acid (Ga-HBED-CC). With use of the Farr assay, binding studies with the 67Ga-labeled chelate and three clones of anti-chelate Mabs showed that none of the Mabs were able to precipitate more than 50% of the Ga-chelate, suggesting an enatiomerism of the Ga-chelate and a sensitivity of the Mabs to either one or the other chelate enantiomer. This could be confirmed by comparing the circular dichroism spectra of the Ga-chelate fractions that passed affinity columns containing the Mabs immobilized on sepharose without retention. With use of a Ga-HBED-CC enantiomer, whole-body retention in mice, preinjected with the corresponding anti-metal chelate Mab of ca. 70% ID, was measured compared to 2.1% retention in mice not preinjected with the Mab. Due to the high affinity of chelate-to-Mab binding in vivo, bispecific antibody conjugates prepared from the fragments of the anti-Ga-chelate Mab might be suitable for pretargeted immunoscintigraphy with the short-lived positron-emitter 68Ga.

[A study on EDTA antigens for detection of IgG antibodies to Legionella pneumophila].

The EDTA and Sonicate antigens used in ELISA for detection of IgG antibodies to Legionella Pneumophila serogroups 1-6 and Tatlock was evaluated. Sensitivity and specificity of EDTA antigens were compared with Sonicate antigens in three groups of subjects. In two serum samples from healthy employees, the Lp1 antibody titers with EDTA and Sonicate antigens were less than or equal to 1:160. Testing seven samples from patients indicated that four samples reacted with titers of 1:1280-2560 to Lp1 with EDTA and Sonicate antigens. But in another three samples, the antibody titers to Lp1 with EDTA antigen were lower 1-3 dilution than Sonicate antigen. One of the lowest titer to EDTA was 1:320 that was interpreted as positive. In all of the seven samples, the antibody titers to Lp4 and Tatlock raised to 1:640-2560 with sonicate antigens and significantly higher than the titers with EDTA antigens (1:320-640). The comparison between the EDTA and Sonicate antigens showed that when the antibody titer with EDTA antigens greater than or equal to 1:320 was regarded as a positive mark the sensitivity of EDTA antigens was similar to Sonicate antigens and the specificity was better than Sonicate antigens. Comparison of EDTA antigen was simple. It is worth to further study.

Bifunctional antibody: a binary radiopharmaceutical delivery system for imaging colorectal carcinoma.

In clinical studies we have evaluated a unique monoclonal antibody-based drug delivery system, a bifunctional antibody designed to deliver imaging or therapeutic agents, such as radioisotopes, drugs, or biologics, to tumor cells, while minimizing the dose to normal tissue. The bifunctional antibody, with one specificity to a tumor-associated antigen (carcinoembryonic antigen) and another specificity to a hapten, is injected and allowed to localize at a tumor site for 4 days. A hapten, tagged with a radioisotope, is subsequently injected for delivery to and capture by the prelocalized antibody at the tumor site. In studies reported here, the sulfhydryl groups of Fab' fragments of ZCE-025 and CHA-255 were linked with bis-maleimidomethyl ether to form an F(ab')2 bifunctional antibody coupled by a stable thioether linkage. EOTUBE, a hydroxyethylthiourido derivative of benzyl EDTA, was used as the hapten carrier of 111In. Fourteen patients 62-82 years old with recurrent or metastatic adenocarcinoma of the colon were studied. Twenty of 21 known lesions were imaged, and eight of nine new lesions were confirmed. With this fundamentally new approach to drug delivery, clearance from normal tissue is rapid, and high tumor:normal tissue ratios are expeditiously achieved.