The hevein domain of the major latex-glove allergen Hev b 6.01 contains dominant T cell reactive sites.
BACKGROUND
Sensitization to natural rubber latex (Hevea brasiliensis) is a major cause of occupational asthma and rhinitis affecting frequent latex-glove users. Hev b 6.01, a known major latex allergen, is cleaved naturally into hevein (4.7 kDa) and a C-terminal fragment (14 kDa). Hevein is an abundant protein in latex-glove extracts. As the immune response to allergens is initiated by activation of allergen-specific CD4(+) T cells, identification of dominant T cell epitopes is crucial for the development of specific immunotherapy.


OBJECTIVE
To identify dominant T cell epitopes of Hev b 6.01 in latex-allergic glove users.


METHODS
Ten latex-allergic frequent glove users and six non-latex-allergic atopic control subjects were selected, based on clinical symptoms and positive latex-specific serum IgE. Serum IgE reactivity to glove extract and recombinant Hev b 6.01 (rHev b 6.01) were analysed by ELISA. Latex-specific short-term oligoclonal T cell lines were generated from peripheral blood of latex-allergic subjects. These lines were tested for proliferative responses to overlapping 20-mer peptides of the Hev b 6.01 molecule. CD4(+) T cell intracellular cytokines, IL-4 and IFN-gamma were assessed following stimulation with immobilized anti-CD3 in the presence of IL-2.


RESULTS
All ten of the latex-allergic patients showed serum IgE binding to glove extract while eight of these also showed IgE binding to rHev b 6.01 by ELISA. Western blotting confirmed reactivity with rHev b 6.01 at around 20 kDa. T cell proliferation assays showed that latex-specific T cell lines from all subjects responded to one or more peptides, with greatest frequency of reactivity to peptides Hev b 6.01 p(10-29) and Hev b 6.01 p(19-38) in the hevein domain. An allergic-type cytokine profile with considerable IL-4 in addition to IFN-gamma was evident from intracellular cytokine staining.


CONCLUSIONS
Hevein is an important T cell as well as B cell immunogen and contains dominant T cell reactive sites.
de Silva
H D
HD
Co-operative Research Centre for Asthma, Sydney, Australia.
Gardner
L M
LM
Drew
A C
AC
Beezhold
D H
DH
Rolland
J M
JM
O'Hehir
R E
RE
D000328:Adult; D000368:Aged; D000485:Allergens / Q000032:analysis / Q000235:genetics / Q000276:immunology*; D000595:Amino Acid Sequence; D052179:Antigens, Plant; D023181:Antimicrobial Cationic Peptides; D002460:Cell Line; D002478:Cells, Cultured; D016207:Cytokines / Q000096:biosynthesis; D018604:Epitope Mapping; D018984:Epitopes, T-Lymphocyte / Q000032:analysis*; D005260:Female; D017575:Gloves, Protective / Q000009:adverse effects; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D007840:Latex / Q000276:immunology*; D020315:Latex Hypersensitivity / Q000276:immunology*; D008213:Lymphocyte Activation / Q000276:immunology; D008875:Middle Aged; D008969:Molecular Sequence Data; D009784:Occupational Diseases / Q000276:immunology*; D037121:Plant Lectins / Q000276:immunology; D010940:Plant Proteins / Q000032:analysis / Q000235:genetics / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology
D000485:Allergens; D052179:Antigens, Plant; D023181:Antimicrobial Cationic Peptides; D016207:Cytokines; D018984:Epitopes, T-Lymphocyte; C097982:Hev b 6.01 protein, Hevea brasiliensis; D007840:Latex; D037121:Plant Lectins; D010940:Plant Proteins; C045875:hevein; D007073:Immunoglobulin E