Production of human T cell growth factor.

We provide here a protocol for production of T cell growth factor (TCGF) using cells isolated from defibrinated blood. Whether combined in allogeneic pools or tested as single donors, these cells consistently yield high activity TCGF, following PHA stimulation. Protocols using cells isolated from heparinized blood have often included addition of indomethacin or removal of adherent cells, or both, to overcome the problem of frequent nonproducing cultures. Our failure to find nonproducing cultures using this source of cells suggests that inhibitory cells or factors are removed by the blood clot formed during defibrination. A distinct economic advantage is gained by using these cells, not only because of the reliability of obtaining active supernatants, but also because the same blood can be used for preparation of a serum pool for cell cultures and the erythrocytes are useful for absorption of contaminating PHA present in the TCGF-containing media. Not only can defibrinated blood leukocytes be stimulated by PHA to release TCGF, but when cultured in allogeneic mixtures containing no PHA, they also release active TCGF.