Allergen-specific induction of interleukin-2 (IL-2) responsiveness in lymphocytes from children with asthma. I. Antigen specificity and initial events of the induction.

Interleukin-2 (IL-2) responsiveness of Dermatophagoides farinae (Df)-stimulated lymphocytes from children with bronchial asthma was studied. Six-day culture of lymphocytes from allergic patients increased after an additional 3 days of incubation with recombinant IL-2. This phenomenon was not observed when the lymphocytes of patients allergic to Df were stimulated with ovalbumin (OVA). Normal lymphocytes stimulated with Df expressed Tac antigen (low-affinity IL-2 receptor) but, in contrast to the patients' lymphocytes, did not absorb nor respond to IL-2. Nonadherent responder cells cultured with Df-pulsed autologous adherent cells acquired IL-2 responsiveness, but those cultured with OVA-pulsed adherent cells did not. The monoclonal antibody to HLA-DQ framework (Leu 10 and clonab DQ), but not to HLA-DR framework (OKIa1) and HLA-DP (HLA-DP and clonab DP-DR), blocked the antigen-presenting cells from inducing IL-2 responsiveness. Nonadherent responder cells depleted of OKT4 (CD4)-positive cells failed to acquire IL-2 responsiveness, whereas depletion of OKT8 (CD8) cells had no impact. Taken as a whole, the results indicate that DQ-bearing adherent cells from allergic donors play a key role in presenting Df antigen to allergen-specific responder T cells, which are very likely to be members of the OKT4 positive subset.