Detection of cALLA positive cells in the human normal peripheral blood by microimmunofluorometry and their fate...

A very sensitive measuring device for immunoflourescence and a new evaluation method were applied to detect the common acute lymphoblastic leukaemia antigen (cALLA) on individual cells from normal peripheral blood. Using a monoclonal and a polyclonal antiserum a small % (about 10%) of cells was shown to carry this antigen. In double-labelling experiments these cALLA positive cells were shown not to carry surface immunoglobulin, and very little T-antigen if any. During a 13-d cultivation of normal mononuclear blood cells in diffusion chambers, the cALLA positive cells disappeared but could be detected again on day 13 at a frequency comparable to that before culture. Proliferation is discussed as the mechanism accounting for the reappearance of the cALLA positive cells, perhaps due to the influence of the T-helper cells generated during culture.