Immunologic Definition of Lymphocytes: Functions and Markers

Abstract

In 1956 the lymphocyte was widely recognized as a cell of importance in the immune response but there was little precise information. Since that time many changes have taken place and the broad concept of a bimodal lymphoid system has emerged. The two modalities relate both to the immediate anatomic origin of the two cell populations in their virgin antigenically unstimulated condition and to their functional aptitudes. Cells from the thymus are referred to as T-lymphocytes and those from the bone marrow (or bursal equivalent) are named B-lymphocytes. These latter, B, cells are without doubt responsible for antibody production in the classical sense but in some as yet undefined way they are assisted in the full discharge of this function by the T-lymphocyte population. The T-lymphocyte is probably capable of cytotoxic activity against foreign or virally infected cells in addition to its “helper” cell function in antibody responses. There are many complexities recognized in the B- and T-cell system most of which at the present time relate to experimental animal situations from which much of our present concept of lymphocyte heterogeneity derives.