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  • 1
    ISSN: 1398-9995
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background: Class I chitinase in natural rubber latex (NRL) has been assumed to be an important allergen, especially concerning its cross-reactivity with fruits like avocado and banana.Objectives: The present study aimed to produce a recombinant latex class I chitinase from Hevea brasiliensis leaves and to study its immunoglobulin (Ig)E-binding reactivity.Methods: A class I chitinase-specific complementary DNA from H. brasiliensis leaves was synthesized, subcloned, sequenced and overexpressed in fusion with the maltose-binding protein (MBP) in Escherichia coli. The IgE-binding reactivity of this protein was studied by the Pharmacia CAP SystemTM and by immunoblot experiments using sera from latex-allergic patients.Results: The rHev b 11.0102 was found to have a length of 295 amino acid residues and contains an N-terminal hevein-like domain with a 56% homology to hevein. Analysis by the CAP method revealed the presence of rHev b 11.0102-specific IgE antibodies in 17 of 58 sera (29%) of IgE-mediated latex-allergic subjects tested. Immunoblot analysis of the MBP–rHev b 11.0102 fusion protein and the MBP carrier protein as a negative control confirmed the IgE-reactivity of rHev b 11.0102.Conclusion: Due to its IgE-reactivity rHev b 11.0102 represents an allergen of intermediate prevalence in NRL. Its property to cross-react with certain fruits makes it an important supplement in the diagnostic panel of recombinant NRL allergens.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Allergy 50 (1995), S. 0 
    ISSN: 1398-9995
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The cross-reactivity of IgE antibodies recognizing epitopes of latex allergens and papain was studied in sera of 36 latex-exposed subjects and 22 papain workers. Eight out of 24 latex-sensitized persons also showed positive reaction to papain in the CAP assay (mostly of low or moderate degree). On the other hand, six out of the 12 sensitized papain workers also revealed IgE binding to latex allergen(s). Reciprocal inhibition experiments confirmed that groups monosensitized to one of the two allergens can be separated from a group showing partial or nearly complete immunologic cross-reactivity. Papain inhibited IgE binding by 20–33% in these subjects, whereas IgE binding to papain was strongly blocked in most cases. Comparison between the primary sequences of Hev b 1, a major latex allergen, and papain suggests that the cross-reactivity may be due to several identical trimers and tetramers.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1398-9995
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background:  Multiple immunoglobulin E (IgE)-binding proteins in natural rubber latex extracts have been identified. In the case of Hev b 6 a differentiation was made between the precursor protein prohevein (Hev b 6.01) and its two post-transcriptionally formed proteins, the N-terminal hevein (Hev b 6.02) and the C-terminal domain (Hev b 6.03). All three components act as independent allergens. The aim of this study was a detailed analysis of the T-cell responses and the IgE-binding capacity of Hev b 6.01, Hev b 6.02 and Hev b 6.03 by using these allergens as recombinant maltose-binding fusion (MBP) proteins and the usage of synthetic modified hevein peptides.Methods:  Latex-allergic health care workers (HCWs) suffering from rhinitis, conjunctivitis, contact urticaria and/or asthma with increased specific IgE-antibodies to latex were tested for their IgE-binding capacity and T-cell reactivity (by proliferation response) to the recombinant MBP-rHev b 6.01, MBP-rHev b 6.02, MBP-rHev b 6.03, to native Hev b 6.02, to modified hevein peptides and wheat germ agglutinin (WGA). For testing of the human leucocyte antigen (HLA) class II restriction of MBP-rHev b 6.01 induced peripheral blood mononuclear cell (PBMC) responses, monoclonal antibodies against HLA-DR, HLA-DP or HLA-DQ were added.Results:  Seventeen of 18 (94%) serum samples from latex-allergic HCWs had increased levels of specific IgE to MBP-rHev b 6.01, 16 (89%) to MBP-rHev b 6.02 and 13 (72%) to MBP-rHev b 6.03. A significant difference existed between the specific IgE-values of MBP-rHev b 6.02 and MBP-rHev b 6.03 (P 〈 0.01). Proliferation responses of PBMC of the same 18 latex-allergic patients were positive for MBP-rHev b 6.01 and MBP-rHev b 6.03 in 83 and 67% of the tested PBMC suspension, whereas the proliferation responses induced with MBP-rHev b 6.02 or native Hev b 6.02 were very low (5.6 and 22.2%). Sera from nine additional latex-allergic patients showed specific IgE binding to the native Hev b 6.02, but none of these sera showed specific IgE binding to the modified Hev b 6.02-peptides [whereby all eight cysteine residues were substituted by serine (C → S) or by alanine (C → A)]. Proliferation responses induced by the modified Hev b 6.02 peptides were not significantly different from that induced by Hev b 6.02. Potential HLA-DR4Dw4(DRB1*0401)-restricted T-cell epitopes of Hev b 6.01 predicted by two computer algorithms were only found in the Hev b 6.03-part of Hev b 6.01.Conclusion:  In the Hev b 6.01 precursor the regions responsible for IgE binding and those for inducing the T-cell proliferation responses are settled in different parts of the protein. The Hev b 6.02 domain is responsible for IgE binding and carries discontinuous B-cell epitopes whereas Hev b 6.03 is a better inducer of a proliferation response and contains HLA-DR4-binding motifs.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Clinical & experimental allergy 26 (1996), S. 0 
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Allergy 57 (2002), S. 0 
    ISSN: 1398-9995
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Copenhagen : Munksgaard International Publishers
    Allergy 56 (2001), S. 0 
    ISSN: 1398-9995
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Copenhagen : Munksgaard International Publishers
    Allergy 55 (2000), S. 0 
    ISSN: 1398-9995
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background: Profilin (Hev b 8) in natural rubber latex (NRL) has been assumed to be an important allergen. Since latex profilin has a molecular mass similar to two other latex allergens (Hev b 1 and Hev b 6.03) in the 14-kDa range, it is difficult to obtain sufficient amounts of purified native profilin for investigations and diagnostics. The present study aimed to produce recombinant latex profilin (rHev b 8) and study its IgE-binding reactivity. Methods: A profilin-specific cDNA encoding the latex profilin from Hevea brasiliensis leaves was synthesized and subcloned, and the rHev b 8 was overexpressed in fusion with the maltose-binding protein (MBP) in E. coli. The IgE-binding reactivity of rHev b 8 was studied by immunoblotting, immunoblot inhibition experiments, and the Pharmacia CAP method, with 25 sera from health-care workers with latex allergy and 17 sera from latex-sensitive spina bifida patients. Results: rHev b 8 was found to have 131 amino acids and a sequence identity of 75% with birch profilin (Bet v 2). Analysis by the CAP system revealed the presence of rHev b 8-specific IgE antibodies in two out of 17 sera from spina bifida patients and in five out of 25 sera (20%) from health-care workers. Two subjects of the latter group with rHev b 8-specific IgE showed negative results in the skin prick tests with tree-pollen extracts and had no IgE to rBet v 2, indicating the presence of IgE-binding epitopes on the Hev b 8-molecule which do not cross-react with birch profilin. Immunoblot inhibition assays using MBP-rHev b 8 as inhibitor confirmed the presence of latex profilin in the NRL extract. IgE binding to the native latex profilin could be completely inhibited by the MBP-rHev b 8. Conclusions: Latex profilin represents a minor allergen in NRL and may have IgE-binding epitopes different from Bet v 2.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 0378-1119
    Keywords: Chironomidae ; Insecta ; Recombinant DNA ; bacteriophage λ ; genomic library ; haemoglobin gene evolution
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-0738
    Keywords: Key words Styrene ; Styrene-7 ; 8-oxide ; Human white blood cells ; 8-Hydroxy-2′-deoxyguanosine ; Oxidative DNA damage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Styrene-7,8-oxide (SO), the major in vivo metabolite of styrene, is a genotoxic compound and a potential carcinogenic hazard to occupationally exposed workers. The aim of the present work was to investigate the ability of styrene exposure to induce formation of 8-hydroxy-2′-deoxyguanosine (8-OHdG) in white blood cells (WBC) of boatbuilders occupationally exposed to styrene. The study of these adducts was conducted to see if styrene exposure can cause oxidative damage of DNA. The 8-OHdG/105 dG ratio from 17 styrene-exposed workers showed significant increases (mean ± SD, 2.23 ± 0.54, median 2.35, P 〈 0.001) in comparison to the controls (1.52 ± 0.45, median 1.50). However, 11 out of 17 workers who were between the ages of 32 and 60 years and had been occupationally exposed to styrene for 〉10 years showed higher 8-OHdG/105 dG ratios (2.31 ± 0.62, median 2.37) in comparison to 6 workers with 〈6 years of occupational styrene-exposure (2.11 ± 0.36, median 2.05; P 〉 0.05, no significant difference between the two groups of workers). The studies presented here provide an indication that styrene exposure can result in oxidative DNA damage.
    Type of Medium: Electronic Resource
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