SURFACE-PROPERTIES OF LDL-BINDING LYMPHOCYTES IN HUMAN PERIPHERAL-BLOOD

  • 1 January 1980
    • journal article
    • research article
    • Vol. 39  (3) , 311-316
Abstract
Surface properties of low density lipoprotein (LDL)-binding lymphocytes were evaluated to determine whether LDL binds with a subpopulation of human peripheral blood lymphocytes (PBL). B[bone marrow-derived]- and T[thymus-derived]-cell rich fractions were prepared from PBL using E[erythrocyte]-rosette formation or nylon reticulum columns. Binding of FITC[fluorescein isothiocyanate]-labeled LDL with these cell fractions was determined with a fluroescent microscope and a fluorescence-activated cell sorter (FACS II). Specificity of the binding was evaluated by a dose-dependent inhibition of LDL binding with the addition of unlabeled lipoproteins. In parallel studies, surface properties including E-rosette formation, surface immunogolbulins [Ig] receptors for IgG-Fc and human and mouse C3 [complement component 3] were examined. LDL binding lymphocytes were enriched in the B cell rich fractions and depleted in the T cell rich fraction. FITC-LDL binding lymphocytes were selectively collected by the FACS II. These LDL binding cells restored surface Ig after incubation in serum-free medium following trypsinization. The majority of lymphocytes stimulated by PHA [phytohemagglutinin] and PWM [pokeweed mitogen] in vitro bound with LDL. LDL binds with B cells in fresh human PBL, while it binds with B and T cells in mitogen-stimulated lymphocytes. The selective collection of LDL binding lymphocytes by the FACS II can apparently be applied to the evaluation of cellular interaction of these cells in various immunological reactions.