The value of identifying major T cell epitopes of clinically important allergens.

flare reactions at the injection site to severe life-threatening anaphylactic reactions. Consequently, a multitude of strategies on how to interfere with the unintended allergenic activity of whole allergens has been developed in the past. These strategies include, but are not restricted to, the application of variant forms of major allergens such as chemically modified allergens, allergen fragments, hypoallergenic variants and linear peptide sequences of various lengths, which are unable to cross-link receptor-bound IgE and thus should reduce the risk for the sensitized patients. The article by Etto et al. [3] published in a previous issue of International Archives of Allergy and Immunology provides a systematic identification of T cell-reactive peptides from Pas n 1. Their objective was in fact the characterization of T-cell-reactive sequences within this allergen to be able to identify potentially useful peptide candidates, which could be used as potential therapeutics later on. Given the per definitionem low allergenicity/immunogenicity of such peptides, how, then, would future patients benefit from peptide identification and characterization? Along these lines, Worm et al. [4] have very elegantly demonstrated that the T-cell-specific peptides of major allergens – when injected intradermally into allergic patients – have the potential to modify the allergic immune Bahia grass is a subtropical grass species native to Argentina, Brazil, Paraguay and Uruguay, which has recently been introduced into the more temperate zones of the globe to grow in lawns or for agricultural purposes [1] . In temperate climate zones Paspalum notatum flowers and pollinates late into summer and can cause allergic symptoms during an extended period of time when compared to other grasses. In subtropical regions, it can be regarded as a perennial species. The immunoglobulin E (IgE) response to the major/ group 1 Bahia grass pollen allergen, Pas n 1, involves monospecific entities which react solely with Pas n 1, but also cross-reactive species, which bind to allergens of other grass species, e.g. Lol p 1 [Rye grass (Lolium perenne) ]. The observed cross-reactivity is, however, not unexpected, given the high-degree of sequence identity of major pollen allergens of different grass species. While specific immunotherapy of grass pollen allergy is an established and disease-modifying form of causative treatment [2] , not all patients with this allergy are eligible for this treatment modality and side effects caused by intact allergens used for specific immunotherapy represent a non-negligible risk factor for adverse events. Intact, fulllength native allergen molecules have the potential to trigger IgE cross-linking on effector cells and to elicit immediate immune reactions, ranging from mild wheal and Published online: August 30, 2012