In vitro Cytodifferentiation of Human Blood Lymphocytes

The proliferation of human blood lymphocytes after incubation with either antigen or nonspecific mitogens indicates a process of differentiation. This assumption is supported by several findings:
The small lymphocytes profoundly change their cytological structure, as transformed cells following stimulation by PHA, Con. A, tuberculin and MLC had the ultrastructural characteristics of immunoblasts. Blastoid transformed cells with a highly developed vacuolar apparatus were observed in those cultures stimulated by PHA and ALS.
This differentiation is paralleled by the development of some functions which characterize T-derived lymphocytes. It was demonstrated that the lymphocytes stimulated by these agents secrete mediators (i.e. a migration inhibition factor) and acquire killer properties. The steps of the cytotoxic process were studied using electron microscopy.