Differentiation of human bone marrow cells into T lymphocytes by in vitro incubation with thymic extracts.

Abstract

Extracts of human or calf thymus influence differentiation of human bone marrow cells in vitro. Incubation of a putative stem cell fraction of human marrow with extracts of thymus for a period of 2 hr led to the appearance of lymphocytes with surface antigens recognized by a highly specific anti-T-cell antiserum. To a lesser degree, development of lymphocytes having the capacity to form rosettes with sheep erythrocytes was observed. Treatment of the so-called stem cell fraction with thymic extracts did not yield cells responsive to mitogenic influences of phyto-haemagglutinin or allogeneic cells. This model should permit further analyses of immunodeficiency diseases and provide a useful technique for purification and analysis of thymus extracts active with human haematopoietic cells.