Mice homozygous for the lymphoproliferation (lpr) gene spontaneously develop autoimmune syndrome. These mice were characterized by the massive accumulation of double negative (DN) T cells. Although peripheral T cells in normal mice do not express J11d antigen, those abnormal DN T cells in autoimmune-prone mice express J11d antigen. In this study, the mechanisms that control the expression of J11d antigen are analyzed. High concentration of calcium ionophore alone induces the expression of J11d antigen, but not of CD4. CDS, and activation antigens such as interleukin 2 receptor as well as transfemn receptor by J11d−DN T cells from lpr mice. The expression of J11d antigen is primarily regulated at the transcription level rather than the post transcription level. Experiments using metabolic inhibitors reveal that the induction of J11d antigen requires the activation of not only a Ca2+/calmodulin- but also protein kinase C-dependent signaling pathway. Furthermore, J11d−DN thymocytes from control mice share the similar functional property with DN lpr T cells in J11d antigen inducibility.