Cell surface differentiation of acute lymphoblastic call-type leukemias in diffusion chambers

Acute lymphoblastic leukaemia cells in the diffusion chamber: change of surface phenotype during the culture period

Peripheral blast cells from patients with acute lymphoblastic leukaemia were cultured in the diffusion chamber system. On different harvesting days the cALL antigen, surface immunoglobulin and T-cell antigen were investigated by direct immunofluorescence. Each cell type investigated showed a different response throughout culture, the commonest change observed being development into the B-cell axis. Our data demonstrate that the differentiation stop of a leukaemic cell can be overcome by using the diffusion chamber system. The data therefore give some insight into the stage of developmental arrest in acute lymphoblastic leukaemia.

Discrimination in immunofluorescence between labeled and unlabeled cells by quantitative microfluorometry and computer analysis

An automated procedure for discrimination in immunofluorescence between antibody-labeled and unlabeled cells has been developed on the basis of microfluorimetric determination of intensity distributions. After smoothing the raw data for irregularities caused by the scoring statistics optimum fit of the negative distribution to the corresponding positive one was achieved. The procedure was tested in a model system by mixing various known proportions of immunofluorescence-negative and -positive plastic beads. In addition, variable mixtures of T-negative CLL cells and normal mononuclear peripheral blood cells were labeled with FITC-conjugated anti-T-antiserum. The expected percentage of T-positive peripheral blood cells agreed satisfactorily with the data measured and computed. Finally, the measured percentage of Ig-positive mononuclear cells from normal peripheral blood was in agreement with the values obtained by other techniques.