Human primary lymphocyte colony formation in agar culture: polyclonal origin and significance.

Primary human lymphocyte colonies, which grow on the surface of agar culture under PHA stimulation, arise from more than one progenitor cell: they contain both type A and B of G6PD when the donor is heterozygous for the isoenzymes. The distribution pattern of electrophoretic bands indicates that, on the average, two T lymphocyte clones proliferate per colony. Colony formation in the present circumstances appears as an in vitro system more suitable for the study of cellular cooperation between a limited number of cells than for the characterization of immature lymphocyte precursors in man.