MULTIPLE B-CELL AND T-CELL EPITOPES ON A MAJOR ALLERGEN OF KENTUCKY BLUEGRASS POLLEN

The B- and T-cell epitopes of a recombinant grass allergen, rKBG60, we re delineated using a set of overlapping synthetic peptides. Direct bi nding by enzyme-linked immunosorbent assay (ELISA) utilizing serum poo ls led to the identification of 13 murine immunoglobulin-, and nine to 13 human IgG- and five to seven human IgE-reactive overlapping peptid es. Of the peptides which bound to human IgE antibodies, all but three peptides bound to human and/or murine IgG antibodies. Furthermore, ei ght out of 12 synthetic peptides induced antigen-specific antibodies i n mice, suggesting that these peptides contained epitopes that recogni zed and/or induced T cells. These results, in conjunction with cross-r ecognition of different peptides at the C-terminus of rKBG60 by antibo dies to neighbouring or non-overlapping peptides suggest that the C-te rminus of this antigen represents a dominant antigenic and allergenic site. Peripheral blood mononuclear cell (PBMC) proliferation studies u sing these synthetic peptides for 13 grass allergic individuals indica ted that seven potential human T-cell epitopes exist on this allergen. Taken together, the results demonstrate that multiple B- and T-cell e pitopes exist on this major group of grass allergens, the majority of which are localized at the C-terminus of this antigen.