Regulatory T Lymphocytes

Since Gowans first discovered the importance of lymphocytes in the immune response [1], a gradual understanding of their biology has evolved. Initially, B lymphocytes, the effector cells of humoral immunity, were studied in great detail. Largely because of the ability to obtain huge quantities of homogeneous antibodies-the B cell's primary product-through the study of multiple myeloma, tremendous gains were made in understanding the B lymphocyte's active role in immunity. The T cell, however, remained more intractable; without the ease of obtaining an entity analogous to an antibody molecule, other approaches were necessary. The biology of cytotoxic T lymphocytes was studied by examining their ability to lyse foreign cells. Yet the cells which are most important in understanding the physiologic control of the immune response, the regulatory T lymphocytes, have been the most difficult to comprehend. In June of 1979, a symposium sponsored by Columbia University was held on this topic, bringing together most of the world's experts in this area. The proceedings of this meeting, the fourth of the P. and S. Biomedical Sciences Symposia, edited by Benvenuto Pernis and Henry J. Vogel, represents an outstanding summary of work in this field. The volume is divided into seven sections, initially examining T cell receptors and T subpopulations before going into detailed discussions of both murine and human helper and suppressor T lymphocytes. Finally, regulatory T cell circuits are described in an attempt to synthesize present knowledge in the area into a coherent model. The book first examines one of the more basic yet elusive characteristics of T lymphocytes, the T cell receptor, determinant of T cell specificity. Although it is well documented that T lymphocytes do not bear conventional immunoglobulin molecules or intact L chains, it has been elegantly shown that they do express idiotypic determinants shared by B cells specific for the same antigen. One approach described has been to try to propagate clones of T cells which secrete soluble molecules mediating their antigen-specific regulatory functions, analogous to studying B cells through their immunoglobulins. Another approach to studying T lymphocytes has been to take advantage of the cell surface differentiation antigens which are specific for various sub-classes of T lymphocytes. With the use of monoclonal antibodies against these markers, a more detailed analysis of T function can be performed. Employing a fluorescence-activated cell sorter, for example, one is able to determine the fraction of cells expressing a given differentiation …