RECOGNITION OF T-CELL EPITOPES AND LYMPHOKINE SECRETION BY RYE GRASS ALLERGEN LOLIUM-PERENNE I-SPECIFIC HUMAN T-CELL CLONES

T cell lines (TCL) and CD4(+) T cell clones (TCC) with specificity for the rye grass allergen Lolium perenne (Lol p) I were isolated from th e blood of nine donors, six having active atopic disease, two being in remission, and one having IgE anti-Lol p I Abs but not atopic disease . The T cell epitopes of Lol p I were determined by TCLs and TCCs reac tivity with 23 overlapping, 20 amino acid-long peptides spanning the e ntire length of the 230 amino acid-long allergen. In addition, the Th subsets (Th1, Th2, Th0, Thp) were determined by measuring IL-2, IFN-ga mma, and IL-4 in the supernatants of TCC activated with Lol p I and ir radiated APC. TCC from individuals from which a large panel of clones were obtained from 10(5) PBMC initial cultures recognized multiple pep tides (5-9) and of 23 overlapping peptides a total of 16 were recogniz ed by at least one TCC from one of the patients. These 16 peptides wer e derived from all areas of the Lol p I molecule, indicating the abili ty of human Th cells to recognize many peptide epitopes on Lol p I. Al though no clear cut immunodominant peptides were detected, T cell clon es of 50% of the patients reacted with peptide 191-210. There was no c orrelation between peptide epitope reactivity and lymphokine secretion pattern of the TCC. Of 12 TCC obtained from six patients with active atopic disease, four (33%) were of Th1, five (42%) of Th2, one (8%) of Thp, and two (17%) of Th0 type. Of 14 TCCs isolated from three atopic donors in remission, five (36%) were of Th1, three (21%) of Th2, four (29%) of Thp, and two (14%) of Th0 type. The data demonstrate that T cells from rye grass pollen allergic patients can recognize multiple p eptide epitopes on Lol p I scattered over the entire molecule. No corr elation existed between epitope reactivity and lymphokine secretion pa ttern of the TCC.