T cell derived IgE binding factors inhibit IgE-specific rosettes on basophilic leukaemic cells and lymphocytes

T cell derived IgE-binding factors inhibited the formation of IgE-specific rosettes on both rat basophilic leukaemic cells and lymphocytes. This was demonstrated by IgE-binding factors released from either IgE-pulsed T cells or adherent cells as well as from IgE-binding factor producing hybridomas. The different binding factors inhibited the IgE-rosettes to a different degree when tested on basophils and lymphocytes, most likely due to the higher affinity for IgE of the former cell type. The results indicate that rat basophils and mouse T cells may recognize common epitopes on the Fc portion of IgE.