[Cellular bases of immunological recognition. The precursors of antigen-binding T- and B-lymphocytes and the patterns of their maturation].

The peculiarities of carefully studied immunoglobulin receptors of the specialized clones of B-lymphocytes are described. These latter are precursors of antibody-forming cells but play only a limited role in the recognition of foreign antigens which is realized by T-lymphocytes. The differentiation of T- and B-lymphocytes from the single precursor, a bone marrow stem hemopoietic cell, proceeds in the bone marrow itself, thymus and peripheral lymphoid organs in several discrete stages. At each of these stages the cells have definite properties and, in some cases, may be separated one from another. The modern data are given concerning the properties of cells at every stage of antigen-independent differentiation of T- and B-lymphocytes which proceeds during embryonic and postnatal development, its alternative pathways, factors of regulation, role of local microenvironment and possibilities of modelling in vitro.