CHARACTERIZATION OF GRASS GROUP-I ALLERGENS IN TIMOTHY GRASS-POLLEN

Using Phl p V-depleted timothy grass pollen extract (Phleum pratense) as immunogen, we obtained a monoclonal antibody, QG 4, which recognized proteins of 33, 35, and 37 kd as determined by Western blotting. The antibody cross-reacted with pollen proteins of other grass species in the molecular weight range of 30 to 37 kd. By mean of two-dimensional polyacrylamide gel electrophoresis blot of timothy grass pollen extract, we demonstrated at least seven protein spots two of 37 kd with isoelectric points of 6.4 and 6.6; four of 35 kd with isoelectric points of 65, 68, 7.1, and 73, and one of 33 kd with an isoelectric point of 8.5. These protein spots were also detected by patients' pooled serum. Microsequencing of the 20 N-terminal amino acid residues revealed structures with sequence identities up to 90% to the well-established allergen, Lol p I of ryegrass (Lolium perenne). Therefore we assume that the monoclonal antibody QG 4 recognized the corresponding allergen Phl p I in timothy grass pollen.