The present invention relates generally to molecules such as peptides polypeptides and proteins which interact immunologically with T lymphocytes in subjects having peanut allergy or allergy to other tree nuts and genetic sequences encoding same. These molecules are preferably immuno interactive with T cells in subjects having an allergy to the Ara h 1 allergen. The molecules of the present invention are useful in the development of diagnostic therapeutic and prophylactic agents for conditions characterised by an aberrant inappropriate or otherwise unwanted immune response to Ara h 1 or derivative or homologue thereof.
