St. Jude Children's Research Hospital scientists show that the molecule serves as a bridge between the two arms of the immune system that provides a new mechanism guiding T cell differentiationMEMPHIS, Tenn. , July 22, 2011 /PRNewswire-USNewswire/ -- St. Jude Children's Research Hospital investigators have identified a signaling molecule that functions like a factory supervisor to ensure that the right mix of specialized T cells is available to fight infections and guard against autoimmune disease. The research also showed the molecule, phosphatase MKP-1, is an important regulator of immune balance. Working in laboratory cell lines and mice with specially engineered immune systems, scientists demonstrated that MKP-1 serves as a bridge between the innate immune response that is the body's first line of defense against infection and the more specialized adaptive immune response that follows. The results are published in the July 22 print edition of the scientific journal Immunity. The results raise hopes that the MKP-1 pathway will lead to new tools for shaping the immune response, said Hongbo Chi, Ph.D., assistant member of the St. Jude Department of Immunology and the study's senior author. The co-first authors are Gonghua Huang, Ph.D., and Yanyan Wang, Ph.D., both postdoctoral fellows in Chi's laboratory. The findings provide new details about how dendritic cells regulate the fate of naïve or undifferentiated T cells. Dendritic cells are the sentinels of the innate immune response, patrolling the body and ready to respond at the first sign of infection. Investigators were surprised that a single molecule regulated production of three out of the four major subsets of T cells, which each play different roles. MKP-1 is a negative regulator of the enzyme p38, which is part of the MAP kinase family of enzymes that control pathways involved in cell proliferation, differentiation and death.