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 He vea brasiliensis, cause anaphylaxis in susceptible individuals, especi ally health care workers and children with spina bifida. To identify l atex allergens, we utilized IgE from the serum of a latex-allergic hea lth care worker to screen a cDNA Library from Hevea latex. The identif ied cDNA clone, cDNA Hev b 5, encodes an open reading frame of 163 pep tide residues. Hybridization analysis of cDNA Hev b 5 with RNA extract ed from Hevea tissue indicates that the full-length transcript is abou t 1000 bases. The nucleotide and deduced protein sequences have signif icant homology to sequences from kiwi and potato, which are known to c ause allergic reactions in some latex-allergic patients. Fifty-six per cent of spina bifida patients and 924 of health care workers with late x allergy have IgE specific to the protein encoded by cDNA Rev b 5. A monoclonal antibody raised from a mouse immunized with Hev b 5 binds t o a protein in Hevea latex with an M(r) identical to that of the expre ssed and cleaved recombinant protein. Taken together, these results es tablish that the antigen Hev b 5 contains a major epitope for IgE-medi ated reactions to H. brasiliensis latex products.