Colony growth of human T lymphocytes in agar: effect of a soluble factor from adherent cells

Abstract

When mononuclear cells from peripheral human blood were plated directly in agar medium containing phytohemagglutinin (PHA) and sheep red blood cells and cultured for 6–7 days, discrete colonies of 4–50 lymphocytes were formed. The plating efficiency was one colony per 50–100 cells plated, but this was reduced by approximately 85 % when adherent cells were removed from the mononuclear cell suspension prior to culture. PHA‐induced colony formation by autologous or homologous nonadherent cells could be completely restored by culturing nonadherent cells over a feeder layer of adherent cells or addition of the medium in which adherent cells had been cultured. Thus, adherent cells were presumed to..