Bone marrow differentiation in vitro.

In vitro techniques have proven particularly fruitful for the study of the differentiation of the hemopoietic cells in bone marrow. Progenitor cells can be readily obtained in suspension and in many cases can be induced to grow and differentiate as isolated clones in vitro. At least in vitro, growth and differentiation appear to be regulated by a series of soluble molecules. Recent advances in immunology (the production of inducible T-cell hybridomas and specific T-cell clones) have defined the T-cell as a source of a number of these soluble regulators. Study of the generation of lymphocytes from bone-marrow precursors in vitro, however, remains a challenge.