Use of altered peptide ligands to modulate immune responses as a possible immunotherapy for allergies

Allergies are dramatically increasing in prevalence, and the manage:ment of these diseases is a heavy burden on the health-care systems of developed c ountries. In recent years, many efforts have been made to improve the thera py of allergies and to develop new approaches for immunotherapy. Here we br iefly review the use of peptides to modulate T-cell responses to allergens. We focus mainly on the possibility of using altered peptide ligands (APLs) , i.e., peptides tailored on immunodominant T epitopes and bearing a single amino-acid substitution, as a tool to modulate immune responses to allerge ns. These peptides may be recognized by the specific T cells triggered by t he agonist peptides, but they are unable to elicit T-cell responses; thus, they could be ideal candidates to modulate immune responses to allergens. T he availability of these peptides could allow new approaches for immunother apies.