k218 rHev b 5 Latex

Allergens within Occupational Allergens

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  • Latin name: Hevea brasiliensis
  • Common names: Acidic protein
  • Source material: Recombinant non-glycosylated protein produced in an E. coli strain carrying a cloned cDNA encoding Hevea brasiliensis allergen Hev b 5.
Recombinant allergen
Hevea brasiliensis allergen Hev b 5.
 
Biological function
Unknown, a structural protein

Mw
6 kDa
 
Allergen description
Hev b 5 (1-6) is a potent Latex allergen and is heat-stable (7). Its physiological function is unknown. Hev b 5 exists as multiple isoforms, but only small amounts are present in the non-ammoniated Latex preparations, such as those used for diagnostic tests, and this may help to explain the relatively poor sensitivity of some in vitro tests (8). Therefore, most of the research has been performed with the recombinant form, rHev b 5. In serological tests, 92% of Latex-allergic adult health care workers (HCW) and 56% of the spina bifida (SB) Latex-allergic patients showed Hev b 5- specific IgE antibodies in their sera (4).

It has also been shown that rHev b 5 could be used as a complement reagent to enhance the quantitative performance of Latex ImmunoCAP for allergen-specific IgE measurement (9). A significant number (16%) of serum samples became more strongly positive to the improved k82 (spiked with rHev b 5) than to the regular k82 Latex ImmunoCAP, and a rather small number of previously negative serum samples became positive (9). Hev b 5 may be the missing allergen to fill the diagnostic gap for some allergic patients with clear clinical Latex allergy but with negative serological reactivity (10).

Furthermore, Hev b 5-specific monoclonal antibodies and human IgE from Latex-allergic HCW demonstrate the greater content of Hev b 5 in high-protein powdered glove extracts. This may explain the observed higher frequency of sensitisation to this allergen in HCW (5). The nucleotide and deduced protein sequences or rHev b 5 have significant homology to sequences from Kiwi and Potato, which are known to cause allergic reactions in some Latex-allergic patients (4). The sequence homology (47% sequence identity) between these 2 acidic proteins suggests a molecular explanation for the high frequency of fruit hypersensitivity in Latex-allergic patients (11). A novel gene has been isolated from a Sugar beet cDNA library that resembles members of the Latex allergen Hev b 5 family (12). However, the clinical significance has not been established. Hev b 5 has been identified as a potential candidate for immunotherapy. A recombinant Hev b 5 protein with significantly reduced IgE-binding activity has been described, and this may prove to be a valuable reagent for immunotherapy (3). 

References:

    1. Yeang HY, Chow KS, Yusof F, Arif SA, Chew NP, Loke YH. Appraisal of latex glove proteins in the induction of sensitivity to multiple latex allergens. J Investig Allergol Clin Immunol 2000;10(4):215-22.
    2. Yip L, Hickey V, Wagner B, Liss G, Slater J, Breiteneder H, Sussman G, Beezhold D. Skin prick test reactivity to recombinant latex allergens. Int Arch Allergy Immunol 2000;121(4):292-9.
    3. Beezhold DH, Hickey VL, Sussman GL. Mutational analysis of the IgE epitopes in the latex allergen Hev b 5. J Allergy Clin Immunol 2001;107(6):1069-76.
    4. Slater JE, Vedvick T, Arthur Smith A, Trybul DE, Kekwick RG. Identification, cloning, and sequence of a major allergen (Hev b 5) from natural rubber latex (Hevea brasiliensis). J Biol Chem 1996;271(41):25394-9.
    5. Sutherland MF, Drew A, Rolland JM, Slater JE, Suphioglu C, O'Hehir RE. Specific monoclonal antibodies and human immunoglobulin E show that Hev b 5 is an abundant allergen in high protein powdered latex gloves. Clin Exp Allergy 2002;32(4):583-9.
    6. de Silva HD, Sutherland MF, Suphioglu C, McLellan SC, Slater JE, Rolland JM, O'hehir RE. Human T-cell epitopes of the latex allergen Hev b 5 in health care workers. J Allergy Clin Immunol 2000;105(5):1017-24.
    7. Beezhold DH, Hickey VL, Sutherland MF, O'Hehir RE. The Latex allergen Hev b 5 Is an antigen with repetitive murine B-cell epitopes. Int Arch Allergy Immunol 2004;134(4):334-40.
    8. Beezhold DH, Hickey VL, Slater JE, Sussman GL. Human IgE-binding epitopes of the latex allergen Hev b 5. J Allergy Clin Immunol 1999;103(6):1166-72.
    9. Lundberg M, Chen Z, Rihs HP, Wrangsjo K. Recombinant spiked allergen extract. Allergy 2001;56(8):794-5
    10. Rihs H-P, Raulf-Heimsoth M. Natural rubber latex allergens: Characterization and evaluation of their allergenic capacity. New Horizons, Pharmacia Diagnostics AB 2003;No 3.
    11. Akasawa A, Hsieh LS, Martin BM, Liu T, Lin Y. A novel acidic allergen, Hev b 5, in latex. Purification, cloning and characterization. J Biol Chem 1996;271(41):25389-93.
    12. Fowler MR, Gartland J, Norton W, Slater A, Elliott MC, Scott NW. RS2: a sugar beet gene related to the latex allergen Hev b 5 family. J Exp Bot 2000;51(353):2125-6.

2006



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