Generation of CTL lines using cultured T cells (CTC) as feeder cells. I. Specificity for class I determinants

Lines of cytotoxic T lymphocytes (CTL) may be grown in long-term culture in medium supplemented with Interleukin-2 (IL-2). In most cases a source of feeder cells is also necessary. Because they are available in large numbers, we tested whether cultured T cells (CTC) would serve as feeder cells. We confirmed the observation of others that CTL grown in medium supplemented with IL-2, but in the absence of feeder cells, grew poorly and became less cytotoxic with time. CTL lines directed class I HLA antigens and grown with either x-irradiated peripheral blood lymphocytes (PBL) or x-irradiated CTC proliferated well, were similarly cytotoxic, and demonstrated the same antigenic specificity. By using cells from members of a family in which one offspring had inherited a recombinant chromosome, it was possible to show that sharing of the Class I determinants between the original stimulating cells in the primary culture and the CTC feeder cells was sufficient to enable the maintenance of strongly cytotoxic CTL lines.