Identification, cloning, and sequence of a major allergen (Hev b 5) from natural rubber latex (Hevea brasiliensis).

Proteins in commercial latex products, derived from the rubber tree Hevea brasiliensis, cause anaphylaxis in susceptible individuals, especially health care workers and children with spina bifida. To identify latex allergens, we utilized IgE from the serum of a latex-allergic health care worker to screen a cDNA library from Hevea latex. The identified cDNA clone, cDNA Hev b 5, encodes an open reading frame of 163 peptide residues. Hybridization analysis of cDNA Hev b 5 with RNA extracted from Hevea tissue indicates that the full-length transcript is about 1000 bases. The nucleotide and deduced protein sequences have significant homology to sequences from kiwi and potato, which are known to cause allergic reactions in some latex-allergic patients. Fifty-six percent of spina bifida patients and 92% of health care workers with latex allergy have IgE specific to the protein encoded by cDNA Hev b 5. A monoclonal antibody raised from a mouse immunized with Hev b 5 binds to a protein in Hevea latex with an Mr identical to that of the expressed and cleaved recombinant protein. Taken together, these results establish that the antigen Hev b 5 contains a major epitope for IgE-mediated reactions to H. brasiliensis latex products.