Multiple B‐ and T‐cell epitopes on a major allergen of Kentucky Bluegrass pollen

The B‐ and T‐cell epitopes of a recombinant grass allergen, rKBG60, were delineated using a set of overlapping synthetic peptides. Direct binding by enzyme‐linked immunosorbent assay (ELISA) utilizing serum pools led to the identification of 13 murine immunoglobulin‐, and nine to 13 human IgG‐ and five to seven human IgE‐reactive overlapping peptides. Of the peptides which bound to human IgE antibodies, all but three peptides bound to human and/or murine IgG antibodies. Furthermore, eight out of 12 synthetic peptides induced antigen‐specific antibodies in mice, suggesting that these peptides contained epitopes that recognized and/or induced T cells. These results, in conjunction with cross‐recognition of different peptides at the C‐terminus of rKBG60 by antibodies to neighbouring or non‐overlapping peptides suggest that the C‐terminus of this antigen represents a dominant antigenic and allergenic site. Peripheral blood mononuclear cell (PBMC) proliferation studies using these synthetic peptides for 13 grass allergic individuals indicated that seven potential human T‐cell epitopes exist on this allergen. Taken together, the results demonstrate that multiple B‐ and T‐cell epitopes exist on this major group of grass allergens, the majority of which are localized at the C‐terminus of this antigen.