A Common Allergenic Epitope of Bermuda Grass Pollen Shared by Other Grass Pollens.

The present study disclosed the cross-reactivity between Bermuda grass pollen (BGP) and other grass pollens using monoclonal antibodies (MAbs) and polyclonal antiserum. MAb 9-13, directed against a group of minor allergens of BGP (Cyn d Bd68K, 48K, 38K) was found to cross-react with extracts of ten other grass pollens. Immunoblotting assays illustrated that MAb 9-13 cross-reacted with multiple components of most of these pollens, and the major cross-reactive components had molecular weights of 29-36 kD. The crossreactivity between BGP and Lol pI, the group I allergen of rye grass pollen, was further evaluated; Lol pI was recognized by MAb 9-13, but not by our MAbs/polyclonal antiserum against Cyn dI, the major allergen of BGP. These results suggest that the epitope recognized by MAb 9-13 is a common (C) epitope shared by Lol pI and Cyn d Bd68K, 48K, 38K, and Cyn dI does not share significant antigenicity with Lol pI. In a modified radio-allergosorbent test, IgE antibodies in the serum of BGP-allergic patients reacted mildly with C-epitope-bearing components of both BGP and rye grass pollens, and this binding could be blocked specifically by MAb 9-13. This suggests that in addition to an antigenic cross-reaction, the C epitope can also lead to an allergenic cross-reaction. Copyright 1994 S. Karger AG, Basel