The diabetic BB rat. Neither Th1 nor Th2?

A long term objective of our work has been to identify and characterize the T cells responsible for causing autoimmune type I diabetes in the spontaneously diabetic BB rat. Based on the Th1/Th2 paradigm encompassing "regulated" and "regulatory" T cells, our analyses show that there are very few "regulatory" peripheral Th2 cells. The "regulated" T cells that remain express an unusual, immature phenotype that is neither Th1 nor Th2. Our data also indicate that transcript expression for p56lck, an enzyme required for T cell development, is abnormal in BB peripheral T cells. We discuss the role abnormal transcript expression of p56lck might play in retarding the development of mature regulatory Th2 cells while simultaneously influencing the escape of autoreactive T cells from the thymus.