Regulatory T Cells and Clinical Application

A major process of rediscovery has taken place in the eld of Cellular Immunology over the past 12 years-subsets of T lymphocytes exist that are speci cally d- icated to regulation or as it should be more appropriately termed suppression of all aspects of immune responses. It is certainly appropriate at this time to recall some of the history that lead to the development of the concept of immune r- ulation/suppression. Shortly after the term helper T cells was coined to described lymphocytes that "helped" both humoral and cell-mediated responses, studies from thelaboratoryofthe lateProfessorRichardGershondemonstratedthatundercertain conditions, antigen recognition by T lymphocytes also resulted in the development of cells that are able to suppress immune responses. Unfortunately, research in this eld rapidly shifted from studies of the function of the suppressor T cells to studies of their soluble products that were thought to be shed or secreted T cell receptors. A number of highly complex suppressor cell pathways and cell circuits were dev- opedand werethe subjectsof morethan5,000papersduringthisera. In 1983-1984, this eld completelycollapsed as studies called into question the existence of the I-J region of the mouse major histocompatibility complex that was thought to encode one of the major chains of the suppressor T cell factors.