DIFFERENTIAL BINDING OF LECTINS TO LYMPHOPOIETIC AND MYELOPOIETIC CELLS IN MURINE MARROW AS REVEALED BY FLOW-CYTOMETRY

Murine marrow cells were labeled with a panel of fluorescein-conjugated lectins and analyzed by flow cytometry. All lectins tested [concanavalin A (Con A), phytohemagglutinin (PHA), wheat germ agglutinin (WGA), pokeweed mitogen (PWM), soybean agglutinin (SBA), peanut agglutinin (PNA), lentil lectin (LL)], stained a fraction of marrow cells; the fraction was, over a defined concentration range, linearly related to the logarithm of the lectin concentration. The slope of this titration curve was characteristic of the particular lectin tested but independent of the nominal sugar specificity of the respective lectin. Con A-, PWM- and PNA-labeled marrow cells showed brightly and dimly stained subsets in relative fluorescence intensity distribution histograms at high or intermediate staining concentrations. These subsets were composed of cells with restricted and characteristic size distributions as determined by forward light scatter. Lectin staining patterns of marrow cells from normal mice were compared with those of athymic nude mice and mice with severe combined immunodeficiency (SCID). Normal and nude mice lacked a subset of small cells, dimly stained by Con A and PWM, but brightly stained by PNA. This subset, uniquely defined by the above lectins, appears to correspond to the lymphopoietic marrow compartment.