Characterization of T cell responses to Hev b 3, an allergen associated with latex allergy in spina bifida patients

The prevalence of type I allergy to Hevea brasiliensis latex is particularl y high among individuals with frequent exposure such as health care workers and patients with spina bifida (SB), Due to a birth defect of the spinal c anal and the resulting neurological and orthopedic defects, these patients require multiple surgeries during childhood. SE patients display a unique p attern of sensitization: IgE-reactivity is preferentially directed against Hev b 3 and Hev b 1, two latex allergens with high sequence similarity. In this study, we analyzed the T cell response to Hev b 3 in latex-allergic SE patients using poly-, oligo-, and monoclonal T lymphocyte cultures. All T cell clones (TCC) were CD3/CD4-positive and expressed the alpha beta TCR, A ccording to their cytokine production pattern (IL-4 vs IFN-gamma), 12 of 21 TCC were classified as Th2-like, 12 of 21 were Th1-like, and 7 of 21 belon ged to a Th0-like subset. Using 11 T cell lines and 21 TCC, nine T cell sti mulating fragments were determined out of 52 overlapping 12-mer peptides re presenting the complete amino acid sequence of Hev b 3, Ag presentation of one dominant T cell epitope could be associated with a four-amino acid bind ing motif (YSTS, position 11-13) in the beta 1 chain of HLA-DR molecules ex pressed by the respective patients. No reactivity was observed when Hev b 3 -reactive T cell lines or TCC were incubated with peptides representing hom ologous parts of the Hev b 1 molecule, i.e., no cross-reactivity between He v b 3 and Hev bl at the T cell level was evident.