An acute lymphoblastic leukemia which produces human T cell growth factor.

We report the production of T cell growth factor activity by a PHA stimulated acute lymphoblastic leukemia cell line designated HSB-2. Factor production was enhanced by the addition of phorbol myristate acetate to the cultures. The growth factor will enhance the proliferation of PHA stimulated thymocytes and sustain the proliferation of growth-factor dependent human T cell blasts. The characteristics of the cell line are described.