Anti-CD45R antibody-treated normal lymphocytes respond to interleukin 2 (IL2) after stimulation by allergens

Interleukin 2 (IL2) responsiveness was specifically induced by Dermatophagoides farinae (Df) antigen in Df-sensitized lymphocytes from asthmatic children, but not in normal lymphocytes. Df-induced IL2 responsiveness was also observed in normal lymphocytes pretreated (Day 0) with anti-CD45R antibody, which recognize suppressor inducer subset among CD4+ T cells. However anti-CD45R antibody was no longer effective when the lymphocytes were cultured for more than one day with the antigen, suggesting its effect in the initial phase of the reaction. The intensity of the response induced in normal lymphocytes by the anti-CD45R was comparable to that of the patients sensitized to the nominal antigen. The response of the patients was no longer augmented by the anti-CD45R antibody. Taken together, these data suggest that even normal lymphocytes have potentiality to elicit Df-induced IL2 responsiveness and it is probably derepressed by inhibiting suppressor inducer subset with the anti-CD45R antibody. Also suggested is a defective suppressor inducer activity in the lymphocytes which may lead to hyperreactivity to allergens in asthmatic children.