T-CELL EPITOPES OF THE MAJOR FRACTION OF RYE GRASS LOLIUM-PERENNE (LOL-P-I) DEFINED USING OVERLAPPING PEPTIDES IN-VITRO AND IN-VIVO .1. ISOALLERGEN CLONE1A

One hundred and fifteen overlapping synthetic peptides spanning the en tire sequence of the isoallergen clone1A of Lol p I from rye grass Lol ium perenne were synthesized by the multi-pin technique. The peptides were overlapping 12mers, offset by two residues and overlapping by 10 residues. Sets of six adjacent overlapping peptides (except pool-1,15, 20) were pooled and were used in vitro and in vivo to map the T cell e pitopes on Lol p I. Six atopics who were skin test and RAST positive t o rye grass showed T cell responses to L. perenne extract (LPE) and it s major fraction (Lol p I). Five out of six showed T cell responses in vitro to peptide pool-17, while five non-atopics did not respond to a ny of the peptide pools. By testing the individual peptides of pool-17 , we have located the T cell epitope on Lol p 1. Interestingly, when w e tested pool-17 and its single peptides in vivo by intradermal skin t esting we found in one patient a typical DTH after 24-48 h to pool-17 and its peptides (peptides 3 and 4) which exactly matched the in vitro responses. By defining the T cell epitopes in this way a greater unde rstanding of the allergic response to pollen will be obtained, and a m ore effective and less dangerous vaccine may be possible for treating patients with hay fever.