CELL GROWTH FACTOR SECRETING HUMAN T - T CELL HYBRIDOMA TABLE I Development and Screening of Human T Cell Hybridomas

The development of human T cell hybridomas secreting immunoregulatory molecules has been an area of recent intense interest and investigation. Functional hybrids derived from both normal and malignant human T cells have been developed. These hybrids have been demonstrated to secrete interleukin 2 (IL-2) 1 (1), killer helper factor (2), and factors that help or suppress immunoglobulin production (3, 4). Application of the hybridization technique of Kohler and Milstein (5) to murine T lymphocytes has yielded an even wider variety of factors with immunoregulatory function (6-9). Factors produced by T cell hybrids have proven to be valuable as a source of purified immunoregulatory molecules for use in immunochemical as well as functional studies. Recent studies (10-12) have demonstrated that exogenous growth factors are necessary to support proliferation of normal murine and human B cells placed in long-term culture. In the past, mitogen stimulation of human peripheral blood lymphocytes (PBL) has been used to produce supernatants with B cell growth factor (BCGF) activity (i0). These conventionally generated supernatants are heterogeneous in composition, vary significantly in their ability to support B cell proliferation, and often contain growth factors for T cells as well as for B cells (13). In the present study, we report the development of a human T cell hybridoma secreting BCGF in the absence of IL-2.