Human T lymphocyte colonies in agar: a comparison with other T cell assays in healthy subjects and cancer patients.

Colonies of human lymphocytes with T cell characteristics will grow in agar from repeated mitotic divisions with phytohaemagglutinin (PHA) stimulation. The colonies comprise spheres of tightly-packed cells with up to 500-1,000 blast-like cells in each colony. 65% of cells from pooled colonies bound AET-treated sheep red cells. 1,100-2,500 colonies/10(6) peripheral blood lymphocytes developed when cell donors were healthy but lower numbers (350-1,000 colonies/10(6) lymphocytes) were detected in blood from cancer patients. Comparison with other non-specific assays of cell-mediated immunity showed that while 66% of cancer patients were anergic (to five recall antigens) and 78% exhibited depressed mitotic activity in standard cultures with low dose PHA, 100% of these patients revealed T cell colony formation below normal. It is suggested that further studies of T lymphocyte colony-forming cells in healthy people and in a number of disease states may significantly advance our understanding of mechanisms of cell-mediated immunity.