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B-cell Epitopes (b-cell + epitope)
Kinds of B-cell Epitopes Selected AbstractsPreparation, physiochemical characterization, and oral immunogenicity of A,(1,12), A,(29,40), and A,(1,42) loaded PLG microparticles formulationsJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 6 2009R. Rajkannan Abstract Alzheimer's disease (AD) is caused by the deposition of ,-amyloid (A,) protein in brain. The current AD immunotherapy aims to prevent A, plaque deposition and enhance its degradation in the brain. In this work, the peptides B-cell epitope A,(1,12), T-cell epitope A,(29,40) and full-length A,(1,42) were loaded separately to the poly (D,L -lactide co-glycolide) (PLG) microparticles by using W/O/W double emulsion solvent evaporation method with entrapment efficacy of 70.46%, 60.93%, and 65.98%, respectively. The prepared A, PLG microparticles were smooth, spherical, individual, and nonporous in nature with diameters ranging from 2 to 12 µm. The cumulative in vitro release profiles of A,(1,12), A,(29,40), and A,(1,42) from PLG microparticles sustained for long periods and progressively reached to 73.89%, 69.29%, and 70.08% by week 15. In vitro degradation studies showed that the PLG microparticles maintained the surface integrity up to week 8 and eroded completely by week 16. Oral immunization of A, peptides loaded microparticles in mice elicited stronger immune response by inducing anti-A, antibodies for prolonged time (24 weeks). The physicochemical characterization and immunogenic potency of A, peptides incorporated PLG microparticles suggest that the microparticles formulation of A, can be a potential oral AD vaccine. © 2008 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 98:2027,2039, 2009 [source] Targeted destruction of the polymerized human serum albumin binding site within the preS2 region of the HBV surface antigen while retaining full immunogenicity for this epitopeJOURNAL OF VIRAL HEPATITIS, Issue 1 2003J.-H. Park summary. The 55-amino acid (a.a.) preS2 region of the hepatitis B virus (HBV) envelope protein is highly immunogenic, and antibodies against this epitope confer seroprotection against HBV infections. Accordingly, various experimental and clinical studies for developing and evaluating HBV vaccines that include this particular epitope have been reported. However, a pitfall in using preS2 epitopes as part of a vaccinating antigen is that polymerized human serum albumin (pHSA), which is a normal constituent of the human serum, binds to and makes complexes with this particular region. Consequently, it is most likely that the antigen epitope is masked by serum pHSA and subsequently not detected by the immune system. To overcome these limitations, a novel single a.a substitute of the preS2 region was designed that corresponds to a tyrosine to serine exchange at position 140 of preS2. Competitive enzyme-linked immunosorbent assay showed that this substitution completely abolishes pHSA-binding activities in the mutated preS2 peptide, and CD spectra analysis revealed that this property might have been induced by slight conformational changes in its secondary structure. Nevertheless, the original B-cell epitope was still preserved in the mutated preS2 as determined by experimental immunization in mice. In this regard, the preS2(120,145/Y140S) sequence may be an HBV vaccine where epitopes, with intrinsic properties have been deleted without affecting the immunogenicity of the epitope itself. It is expected that the inclusion of this point mutated preS2 epitope will improve the efficacy of conventional preS2-containing HBV vaccines. [source] Schistosomamansoni gene GP22 encodes the tegumental antigen Sm25: (1) antibodies to a predicted B-cell epitope of Sm25 cross-react with other candidate vaccine worm antigens; (2) characterization of a recombinant product containing tandem-repeats of this peptide as a vaccinePARASITE IMMUNOLOGY, Issue 8 2000Mary M. Petzke Monospecific antibodies against two putative epitopes of schistosome protein encoded by gene GP22 (182 codons, no introns) were used to probe worm extracts fractionated by lentil-lectin affinity chromatography or by electrophoresis. Anti-peptide-, (codons 70,84) exclusively identifies the N -glycanase-sensitive, 25 kDa tegumental glycoprotein Sm25 in the lectin-bound fraction of detergent-solubilized adult worm extract S3. In contrast, antipeptide-, (codons 151,162) does not react with Sm25 but cross-reacts with other schistosome proteins, including candidate vaccine antigens paramyosin (Sm97) and glutathione-S-transferases (Sm26, Sm28, Sj26). Recombinant protein r4 × 47, constructed to express multiple copies of codon sequence 117,163 (containing ,), reacts with anti-, and is uniquely recognized by protective Fischer twice-infected (F-2x) rat antiserum. Immunization with r4 × 47 induces antibodies with cross reactivities similar to anti-,, but which also recognize Sm25. Despite these cross-reactivities with protective antigens, rodents vaccinated with r4 × 47 were not protected against cercarial infection. On the basis of these data, two hypotheses are proposed: (1) antigenic epitopes other than , are present within the r4 × 47 sequence which induce antibodies reactive with Sm25 and/or (2) peptide-, assumes alternative antigenic conformations, dependent upon the context of neighbouring sequences, some of which mimic epitopes of proteins encoded by other schistosome genes. These mimotopes are not targets of protective antibodies. [source] Crystallization and preliminary X-ray diffraction analysis of the Fab fragment of WO2, an antibody specific for the A, peptides associated with Alzheimer's diseaseACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 5 2008Kwok S. Wun The murine monoclonal antibody WO2 specifically binds the N-terminal region of the amyloid , peptide (A,) associated with Alzheimer's disease. This region of A, has been shown to be the immunodominant B-cell epitope of the peptide and hence is considered to be a basis for the development of immunotherapeutic strategies against this prevalent cause of dementia. Structural studies have been undertaken in order to characterize the molecular basis for antibody recognition of this important epitope. Here, details of the crystallization and X-ray analysis of the Fab fragment of the unliganded WO2 antibody in two crystal forms and of the complexes that it forms with the truncated A, peptides A,1,16 and A,1,28 are presented. These crystals were all obtained using the hanging-drop vapour-diffusion method at 295,K. Crystals of WO2 Fab were grown in polyethylene glycol solutions containing ZnSO4; they belonged to the orthorhombic space group P212121 and diffracted to 1.6,Å resolution. The complexes of WO2 Fab with either A,1,16 or A,1,28 were cocrystallized from polyethylene glycol solutions. These two complex crystals grew in the same space group, P212121, and diffracted to 1.6,Å resolution. A second crystal form of WO2 Fab was grown in the presence of the sparingly soluble A,1,42 in PEG 550 MME. This second form belonged to space group P21 and diffracted to 1.9,Å resolution. [source] Induction of carbohydrate-specific antibodies in HLA-DR transgenic mice by a synthetic glycopeptide: a potential anti cancer vaccine for human useCHEMICAL BIOLOGY & DRUG DESIGN, Issue 3 2003S. Vichier-Guerre Abstract: Over the last few years, anticancer immunotherapy has emerged as a new exciting area for controlling tumors. In particular, vaccination using synthetic tumor-associated antigens (TAA), such as carbohydrate antigens hold promise for generating a specific antitumor response by targeting the immune system to cancer cells. However, development of synthetic vaccines for human use is hampered by the extreme polymorphism of human leukocyte-associated antigens (HLA). In order to stimulate a T-cell dependent anticarbohydrate response, and to bypass the HLA polymorphism of the human population, we designed and synthesized a glycopeptide vaccine containing a cluster of a carbohydrate TAA B-cell epitope (Tn antigen: , -GalNAc-Ser) covalently linked to peptides corresponding to the Pan DR ,universal' T-helper epitope (PADRE) and to a cytotoxic T lymphocyte (CTL) epitope from the carcinoembryonic antigen (CEA). The immunogenicity of the construct was evaluated in outbred mice as well as in HLA transgenic mice (HLA-DR1, and HLA-DR4). A strong T-cell dependent antibody response specific for the Tn antigen was elicited in both outbred and HLA transgenic mice. The antibodies induced by the glycopeptide construct efficiently recognized a human tumor cell line underlying the biological relevance of the response. The rational design and synthesis of the glycopeptide construct presented herein, together with its efficacy to induce antibodies specific for native tumor carbohydrate antigens, demonstrate the potential of a such synthetic molecule as an anticancer vaccine candidate for human use. [source] Preferential recognition of the phosphorylated major linear B-cell epitope of La/SSB 349,368aa by anti-La/SSB autoantibodies from patients with systemic autoimmune diseasesCLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 3 2006A. G. Terzoglou Summary Sera from patients with primary Sjögren Syndrome (pSS) or Systemic Lupus Erythematosus (SLE) often contain autoantibodies directed against La/SSB. The sequence 349,368aa represents the major B-cell epitope of La/SSB, also it contains, at position 366, a serine aminoacid residue which constitutes the main phosphorylation site of the protein. In this study we investigated the differential recognition of the 349,368aa epitope and its phosphorylated form by antibodies found in sera from patients with systemic autoimmune diseases. Peptides corresponding to the sequence of the unphosphorylated (pep349,368aa) and the phosphorylated form (pep349,368aaPh) of the La/SSB epitope 349,368aa, as well as to a truncated form spanning the sequence 349,364aa and lacking the phosphorylation site (pep349,364aa), were synthesized. Sera from 53 patients with pSS and SLE with anti-La/SSB specificity, 30 patients with pSS and SLE without anti-La/SSB antibodies, 25 patients with rheumatoid arthritis and 32 healthy individuals were investigated by ELISA experiments. Autoantibodies to pep349,368aaPh were detected in sera of anti-La/SSB positive patients with a higher prevalence compared to the pep349,368aa (66%versus 45%). Pep349,368aaPh inhibited the antibody binding almost completely (92%), while pep349,368aa inhibited the binding only partially (45%). Anti-La/SSB antibodies presented a higher relative avidity for the phosphorylated than the unphosphorylated peptide. Immunoadsorbent experiments using the truncated peptide pep349,364aa indicated that the flowthrough showed a selective specificity for pep349,368aaPh, while the eluted antibodies reacted with both peptide analogues of the La/SSB epitope. These data suggest that sera from pSS and SLE patients with anti-La/SSB reactivity possess autoantibodies that bind more frequently and with a higher avidity to the phosphorylated major B-cell epitope of the molecule. [source] Hev b 9, an enolase and a new cross-reactive allergen from Hevea latex and moldsFEBS JOURNAL, Issue 24 2000Purification, characterization, cloning, expression Natural rubber latex allergy is an IgE-mediated disease that is caused by proteins that elute from commercial latex products. A complementary DNA (cDNA) coding for Hev b 9, an enolase (2-phospho- d -glycerate hydrolyase) and allergen from latex of the rubber tree Hevea brasiliensis, was amplified by PCR. The PCR primers were designed according to conserved regions of enolases from plants. The obtained cDNA amplification product consisted of 1651 bp and encoded a protein of 445 amino-acid residues with a calculated molecular mass of 47.6 kDa. Sequence comparisons revealed high similarities of the Hevea latex enolase to mold enolases that have been identified as important allergens. In addition, the crucial amino-acid residues that participate in the formation of the catalytic site and the Mg2+ binding site of enolases were also conserved. Hevea latex enolase was produced as a recombinant protein in Escherichia coli with an N-terminal hexahistidyl tag, and purified by affinity chromatography. The yield amounted to 110 mg of purified Hev b 9 per litre of bacterial culture. The recombinant allergen bound IgE from latex, as well as mold-allergic patients, in immunoblot and ELISA experiments. The natural enolase was isolated from Hevea latex by (NH4)2SO4 precipitation and ion exchange chromatography. The natural and the recombinant (r)Hev b 9 showed equivalent enzymatic activity. Patients' IgE-antibodies preincubated with rHev b 9 lost their ability to bind to natural (n) Hev b 9, indicating the identity of the B-cell epitopes on both molecules. Cross-reactivity with two enolases from Cladosporium herbarum and Alternaria alternata was determined by inhibition of IgE-binding to these enolases by rHev b 9. Therefore, enolases may represent another class of highly conserved enzymes with allergenic potentials. [source] Proteome-guided search for influenza A B-cell epitopesFEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 1 2009Guglielmo Lucchese Abstract The influenza A linear peptide epitopes recognized by murine antibodies, and currently cataloged at http://www.immuneepitope.org, were examined for the identity score to the host mouse proteome. It was found that almost all of the linear viral determinants are (or contain) regions formed by pentapeptide fragments with no or only very low similarity to the murine proteins. The present study adds to previous reports in suggesting a main role of amino acid sequence similarity in the modulation and definition of the B-cell epitope repertoire, inspiring innovative vaccine approaches able to avoid cross-reactive autoimmune collateral phenomena, and addressing future research in the study of immunity against the influenza A virus and infectious diseases in general. [source] Hepatitis B virus variants in patients receiving lamivudine treatment with breakthrough hepatitis evaluated by serial viral loads and full-length viral sequencesHEPATOLOGY, Issue 3 2001Chun-Jen Liu Both viral loads and genome variations have been implicated in the pathogenesis of acute exacerbation of chronic hepatitis B. Hepatitis B exacerbation in patients receiving lamivudine treatment represented a unique setting to clarify their importance. Three organ recipients with posttransplantation hepatitis B exacerbation and 3 patients with chronic hepatitis B were studied. All received lamivudine treatment and their alanine aminotransferase (ALT) levels and hepatitis B virus (HBV) loads were regularly followed. Full-length genomic sequences before and during lamivudine treatment were determined in patients who had breakthrough of serum HBV DNA or elevation of serum ALT. Breakthrough of serum HBV DNA occurred after 6 to 15 months of lamivudine treatment in all. A rapid increase of viral load accompanying the emergence of tyrosine-methionine-aspartate-aspartate (YMDD) variant was followed by hepatitis B exacerbation in each patient. The mean number of nucleotide and amino acid substitutions per genome pair was equivalent in immunosuppressed or immunocompetent patients (6.3 vs. 6.3 for nucleotide, P > .05; 6.0 vs. 6.7 for amino acid, P > .05). Changes of nucleotide and amino acid beyond the YMDD motif were distributed along the whole HBV genome but none occurred within the known B-cell epitopes and human leukocyte antigen class I, or II,restricted T-cell epitopes. Our results suggest that a resurgence of viral load rather than changes of the known immunogenic viral epitopes is more closely associated with the development of hepatitis B exacerbation after the emergence of YMDD variants in patients receiving lamivudine treatment. (HEPATOLOGY 2001;34:583-589.) [source] CD40-mediated enhancement of immune responses against three forms of influenza vaccineIMMUNOLOGY, Issue 1 2007Caterina Hatzifoti Summary There is potential for influenza A infections to cause massive morbidity and mortality. Vaccination may be the primary defence against pandemic influenza, and potential pandemic'flu vaccines may be produced conventionally, in embryonated eggs, or as recombinant protein or synthetic peptide vaccines. However the vaccines are produced, the supply may be limiting, and it will be important to enhance the immunogenicity of the vaccines as much as possible. We have shown that conjugation to CD40 binding antibody is a very efficient way of enhancing immune responses against model antigens, but were interested in assessing the effectiveness of this system using influenza vaccines. We produced conjugates of CD40 monoclonal antibody (mAb) and isotype control with three potential influenza vaccines: a peptide-based vaccine containing T- and B-cell epitopes from virus haemagglutinin; a whole, killed virus vaccine; and a commercially produced split virus vaccine. CD40 mAb conjugates in each case were more immunogenic, but the adjuvant effect of CD40 conjugation was greatest with the split vaccine, where antibody responses were enhanced by several hundred-fold after a single immunization, and lymphocyte proliferation in response to antigen in vitro was also strongly enhanced. [source] Identification of a pre-S2 mutant in hepatocytes expressing a novel marginal pattern of surface antigen in advanced diseases of chronic hepatitis B virus infectionJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 5 2000Yu-Fen Fan Abstract Background and Aims: The expression of hepatitis B viral (HBV) antigens in liver tissue reflects the replicative status of chronic HBV infection. We have previously recognized a novel marginal pattern of hepatitis B surface antigen (HBsAg) in hepatocytes, which usually clusters in groups and emerges at the late non-replicative phase. This study was designed to investigate whether the marginal-type HBsAg represented the gene product of a specific HBV-surface mutant. Methods: Microdissection of cirrhotic nodules homogeneously expressing marginal HBsAg was performed on two of 12 resected livers from HBsAg-seropositive patients with hepatocellular carcinoma. The gene presumably encoding marginal HBsAg was polymerase chain reaction (PCR)-cloned, sequenced and analysed. In vitro transfection and expression of the cloned surface mutant plasmids were performed on the Huh7 cell line to illustrate intrahepatic HBsAg expression. Results: Immunohistochemical staining revealed that the marginal HBsAg was positive for pre-S1 and thus contained large surface proteins. The PCR cloning and sequencing of the genes presumably encoding marginal-type HBsAg in both cases revealed the same deletion at the 5, terminus (nt 2,55) of pre-S2. A point mutation on the small-surface (S) antigen was also found in one case. The pre-S2 deletion sequence and the mutation sites of the S gene coincide with human lymphocyte antigen-restricted T- and/or B-cell epitopes. In vitro transfection of the mutant plasmid revealed a blot-like retention or accumulation of HBsAg in the cytoplasm or at the periphery of hepatocytes, accompanied by a decreased secretion of HBsAg in the culture supernatant, mimicking intrahepatic expression. Conclusion: A natural pre-S2 deletion mutant was identified in hepatocytes expressing a novel marginal pattern of HBsAg, which probably contains mutant, large, surface proteins. The biological significance of the pre-S2 deletion mutant should be interesting in view of the clustering proliferation of hepatocytes expressing marginal HBsAg. [source] Machine learning approaches for prediction of linear B-cell epitopes on proteinsJOURNAL OF MOLECULAR RECOGNITION, Issue 3 2006Johannes Söllner Abstract Identification and characterization of antigenic determinants on proteins has received considerable attention utilizing both, experimental as well as computational methods. For computational routines mostly structural as well as physicochemical parameters have been utilized for predicting the antigenic propensity of protein sites. However, the performance of computational routines has been low when compared to experimental alternatives. Here we describe the construction of machine learning based classifiers to enhance the prediction quality for identifying linear B-cell epitopes on proteins. Our approach combines several parameters previously associated with antigenicity, and includes novel parameters based on frequencies of amino acids and amino acid neighborhood propensities. We utilized machine learning algorithms for deriving antigenicity classification functions assigning antigenic propensities to each amino acid of a given protein sequence. We compared the prediction quality of the novel classifiers with respect to established routines for epitope scoring, and tested prediction accuracy on experimental data available for HIV proteins. The major finding is that machine learning classifiers clearly outperform the reference classification systems on the HIV epitope validation set. Copyright © 2006 John Wiley & Sons, Ltd. [source] An in silico method using an epitope motif database for predicting the location of antigenic determinants on proteins in a structural contextJOURNAL OF MOLECULAR RECOGNITION, Issue 1 2006Vincent Batori Abstract Presently X-ray crystallography of protein,antibody complexes is still the most direct way of identifying B-cell epitopes. The objective of this study was to assess the potential of a computer-based epitope mapping tool (EMT) using antigenic amino acid motifs as a fast alternative in a number of applications not requiring detailed information, e.g. development of pharmaceutical proteins, vaccines and industrial enzymes. Using Gal d 4 as a model protein, the EMT was capable of identifying, in the context of the folded protein, amino acid positions known to be involved in antibody binding. The high sensitivity and positive predictive value of the EMT as well as the relevance of the structural associations suggested by the EMT indicated the existence of amino acid motifs that are likely to be involved in antigenic determinants. In addition, differential mapping revealed that sensitivity and positive predictive value were dependent on the minimum relative surface accessibility (RSA) of the amino acids included in the mapping, demonstrating that the EMTs accommodated for the fact that epitopes are three-dimensional entities with various degrees of accessibility. The comparison with existing prediction scales demonstrated the superiority of the EMT with respect to physico-chemical scales. The mapping tool also performed better than the available structural scales, but the significance of the differences remains to be established. Thus, the EMT has the potential of becoming a fast and simple alternative to X-ray crystallography for predicting structural antigenic determinants, if detailed epitope information is not required. Copyright © 2005 John Wiley & Sons, Ltd. [source] Identification of B-cell epitopes of Bet v 1 involved in cross-reactivity with food allergensALLERGY, Issue 4 2009E. Klinglmayr Background:, The pollen-food syndrome (PFS) is an association of food allergies to fruits, nuts, and vegetables in patients with pollen allergy. Mal d 1, the major apple allergen, is one of the most commonly associated food allergens for birch pollen-allergic patients suffering from PFS. Although the reactions are due to cross-reactive IgE antibodies originally raised against pollen Bet v 1, not every Bet v 1-allergic patient develops clinical reactions towards apple. Aim of the study:, We speculate that distinct IgE epitopes are responsible for the clinical manifestation of PFS. To test this hypothesis we grafted five Mal d 1 stretches onto Bet v 1. The grafted regions were 7- or 8-amino acids long encompassing amino acids residues previously shown to be crucial for IgE recognition of Bet v 1. Methods:, A Bet v 1-Mal d 1 chimeric protein designated BMC was expressed in Escherichia coli and purified to homogeneity. IgE reactivity of BMC was tested with patients' sera originating from (i) Bet v 1-allergic patients displaying no clinical symptoms upon ingestion of apples; and (ii) Bet v 1-allergic patients displaying allergic symptoms upon ingestion of apples and other Bet v 1-related foods. Results and conclusion:, Compared to birch pollen-allergic individuals, patients suffering from PFS showed significantly higher IgE reactivity with BMC (chimeric protein). The results suggest that the Mal d 1 regions grafted onto the Bet v 1 sequence comprise important IgE epitopes recognized by Bet v 1-allergic patients suffering from allergy to apples. [source] Identification and characterization of B-cell epitopes of a 53-kDa outer membrane protein from Porphyromonas gingivalisMOLECULAR ORAL MICROBIOLOGY, Issue 2 2001K. Oyaizu We have previously reported that Porphyromonas gingivalis FDC 381 possesses a 53-kDa protein antigen (Ag53) on its outer membrane that evokes a strong humoral immune response in many patients with periodontal disease and that the humoral immune responses to Ag53 differ greatly among patients. To understand how the individual humoral immune system against Ag53 was determined, the regions of Ag53 recognized by specific antibody (B-cell epitopes) and dominant subclasses of serum immunoglobulin G (IgG) against major B-cell epitopes were examined by enzyme-linked immunosorbent assay. This study used sera from six patients with periodontitis, which all reacted strongly with sonic extracts of P. gingivalis 381 and with purified Ag53, and sera from six periodontally healthy children, which did not react with either sonic extracts of P. gingivalis 381 or Ag53. The epitopes were identified using synthetic 5-residue overlapping decapeptides covering the entire Ag53. Thirteen of 89 synthetic decapeptides showed a strong reaction with sera from the periodontal patients, but no reaction with those from the healthy children. Four peptides of 13 exerted different immune responses among patients. Furthermore, restriction analyses of the highly antigenic regions revealed that three sequences, RAAIRAS, YYLQ and MSPARR, were identified as major B-cell epitopes. Additionally, these epitopes were recognized mainly by the IgG2 isotype. These data suggest that the difference of B-cell epitopes might influence individual differences in antibody titer against Ag53 and also that the epitopes recognized commonly by multiple antibodies are quite valuable for peptide vaccine development against P. gingivalis infection. [source] Prediction of residues in discontinuous B-cell epitopes using protein 3D structuresPROTEIN SCIENCE, Issue 11 2006Pernille Haste Andersen Abstract Discovery of discontinuous B-cell epitopes is a major challenge in vaccine design. Previous epitope prediction methods have mostly been based on protein sequences and are not very effective. Here, we present DiscoTope, a novel method for discontinuous epitope prediction that uses protein three-dimensional structural data. The method is based on amino acid statistics, spatial information, and surface accessibility in a compiled data set of discontinuous epitopes determined by X-ray crystallography of antibody/antigen protein complexes. DiscoTope is the first method to focus explicitly on discontinuous epitopes. We show that the new structure-based method has a better performance for predicting residues of discontinuous epitopes than methods based solely on sequence information, and that it can successfully predict epitope residues that have been identified by different techniques. DiscoTope detects 15.5% of residues located in discontinuous epitopes with a specificity of 95%. At this level of specificity, the conventional Parker hydrophilicity scale for predicting linear B-cell epitopes identifies only 11.0% of residues located in discontinuous epitopes. Predictions by the DiscoTope method can guide experimental epitope mapping in both rational vaccine design and development of diagnostic tools, and may lead to more efficient epitope identification. [source] Characterization of thyroglobulin epitopes in Sardinian adults and juveniles with Hashimoto's thyroiditis: evidence against a major effect of age and genetic background on B-cell epitopesCLINICAL ENDOCRINOLOGY, Issue 1 2010Francesco Latrofa Summary Background, Using recombinant human monoclonal thyroglobulin antibodies expressed as Fab molecules (TgAb-Fab), we have recently confirmed the restriction of Tg epitopes in Hashimoto's thyroiditis (HT). Objective, To investigate Tg epitopes of serum TgAb in HT adults and HT juveniles from a geographically isolated area (Sardinia). Design and Patients, Serum TgAb of 39 Sardinian HT adults, 53 Sardinian HT juveniles and 45 non-Sardinian HT adults were evaluated. The binding of serum TgAb to Tg in ELISA was inhibited by four recombinant human TgAb-Fab, identifying Tg epitopic regions A,D. The percentage of Tg binding inhibition was calculated comparing the binding of serum TgAb in presence of each TgAb-Fab with that in its absence. Results, In the whole cohort of 137 patients, A region TgAb-Fab induced the highest levels of inhibition (55·3 ± 17·8%) (mean ± SD). Lower levels of inhibition were induced by TgAb-Fab of regions B (27·8 ± 25·8%), C (26·8 ± 24·6%) and D (17·5 ± 18·4%). In Sardinian HT adults inhibition by TgAb-Fab of regions A, B and C were comparable to Sardinian HT juveniles; the marginal D region TgAb-Fab induced a slightly higher inhibition (22·1 vs. 13·8%; P = 0·034) in the former than in the latter group. In Sardinian and non-Sardinian HT adults inhibitions by the four TgAb-Fab were similar. Conclusions, In HT, the Tg epitope pattern of serum TgAb was similar in juveniles and adults from a geographically restricted area and in two adult populations from different geographical areas. Thus, in HT, neither age nor genetic background appear to influence B-cell epitopes. [source] | |||||||||||||||||||||||||