AN IMMUNOGENETIC ANALYSIS OF T-CELL REACTIVE REGIONS ON THE MAJOR ALLERGEN FROM THE HOUSE-DUST MITE, DER P I, WITH RECOMBINANT TRUNCATED FRAGMENTS

Proliferation assays were used to localize the T-cell reactive sites o n the major allergen from the house dust mite Dermatophagoides pterony ssinus, Der p I. Seven overlapping recombinant fragments of the Der p I molecule, synthesized with the pGEX expression vector system, were u sed to stimulate peripheral blood lymphocytes from 35 HDM-sensitive in dividuals. The fusion fragments were from 39 to 114 amino acids in len gth and spanned the entire Der p I molecule. Significant proliferative responses to one or more of the fragments were evident in 18 of the a llergic individuals, and each of the fragments led to T-cell stimulati on in at least one of the subjects. Although T-cell reactive regions w ere located throughout the molecule, in 12 of the 18 responsive indivi duals, major immunogenic sites were contained within the 56 amino acid s of the N-terminus, and in 11 of these individuals T-cell reactive re gions were only present between amino acid positions 1 and 94. In two individuals reactive sites could be mapped in the C-terminal half of t he molecule, and in five subjects, epitopes were present in both N- an d C-terminal regions. HLA class I and class II DR and DQ specificities were determined serologically in 16 of the 18 individuals, and no str ong pattern of association between HLA type and the T-cell immunogenic region could be detected.