Human primary T-cell lines in lectin-free media

A method of establishing human T-cell lines in tissue culture media containing TCGF but not PHA is described. PBL, initially stimulated by PHA to produce TCGF, continue production for at least 48 hrs after the lectin has been washed off. The TCGF-conditioned medium initiates blast formation of T-cells from freshly isolated PBL and supports indefinite growth of the T-cell blasts from the primary PBL cultures and also from blast-cells obtained from clonally derived T-cell colonies grown in soft agar culture. The established cell lines are identified by cytochemical and biological means as belonging to the T-cell compartment and express spontaneous cytotoxicity against HeLa-cells. The continuously growing T-cells are unable to produce TCGF and depend strictly on external supply of the growth factor. PHA by itself does not support T-cell growth in spite of its ability to elicit a mitogenic response in PBL-cultures. Thus two types of cells must be involved in the mitogenic event: (i) a TCGF-producer and (ii) a TCGF-responder. PHA elicits in the former TCGF production and then TCGF in the later the mitogenic T-cell response. Therefore, not PHA but TCGF might be considered to be the T-cell mitogen.