Analysis of antigenic determinants shared by two different allergens recognized by human T cells: house dust mite (Dermatophagoides pteronyssinus) and chironomid midge (Chironomus yoshimatsui)

To analyse the cross‐reactivity of T‐cell‐mediated immunity between Dermatophagoides pteronyssinus (Dp) and Chironomus yoshimatsui (Cy), the most common allergens in Japan, we established antigen‐specific human T‐cell lines and clones. Some but not all of the Cy‐induced T‐cell lines showed a significant proliferative response not only to Cy, but also to Dp. No T‐cell line responded to other unrelated antigens. When we stimulated the Dp‐induced T‐cell clones with Cy, 3 of the 40 clones (7.5%) showed a significant proliferation, and 2 of the 3 clones produced interleukin‐4 and interferon‐γ, indicating their helper function, Cross‐reactivity was diminished significantly after the absorption of Dp antigen in an anti‐Cy affinity column. The cross‐reactive epitopes were thought to be expressed on the Dp molecule of 45–53 kD, The presence of helper T cells reactive to both allergens suggests a possibility that this cross‐reactivity might be involved in part in the high incidence of allergy to the 2 major allergens.