Non-specific pinocytosis by human endothelial cells cultured as multicellular aggregates: uptake of lucifer yellow and horse radish peroxidase.

We have analyzed the pattern of time-dependent and concentration-dependent incorporation of Lucifer Yellow CH (LY) and Horseradish Peroxidase (HRP) by human umbilical vein endothelial cells cultured on a non-adhesive substratum, where they they become organized into stable, multicellular aggregates. The data were compared with those previously obtained from low-density cultures of non-growing endothelial cells adherent to plastic. While the linear trend of the incorporation kinetics is preserved, the rate of uptake with both time and concentrations is highly dependent on the culture conditions, namely typology of cell-cell and cell-substrate interactions.

A quantitative assessment of non specific pinocytosis by human endothelial cells surviving in vitro.

Human umbilical vein endothelial cells have been assayed in vitro, 24 hrs. after plating, for non specific pinocytic activity. The culture conditions were designed to minimize the exogenous stimulations of pinocytosis, such as those possibly coming from mitotic induction and chemical and contact-dependent signaling.

A murine monoclonal antibody strictly reactive with human peripheral blood monocytes.

We have produced and characterized a novel murine monoclonal antibody (LAM7) of IgG1 isotype which appears specific for peripheral blood monocytes (PBM) on the basis of histochemical and functional studies. By indirect immunofluorescence, including FACS analysis, the antibody reacts with 90 +/- 6% of PBM and with monocytic leukemias, while it is totally unreactive with B and T lymphocytes, platelets, granulocytes, peripheral macrophages, dendritic cells, large granular lymphocytes, and nonmonocytic leukemias. The antigen-presenting capacity of peripheral blood mononuclear cells is abolished by treatment with MoAb LAM7 in an antiglobulin-complement-mediated cytotoxicity test, and restored by addition of purified PBM.

Two murine monoclonal antibodies to peripheral blood monocyte differentiation antigens discriminate within M5 acute non-lymphoid leukemia (ANLL) cells.

Two murine monoclonal antibodies (MoAbs), LAM3 and LAM7 of the IgG1 isotype, which were produced by immunization with normal peripheral blood monocytes (PBM), were assayed in their specificity by indirect immunofluorescence against a panel of normal as well as leukemic cells. Both LAM3 and LAM7 were reactive with PBM while LAM3 also recognized platelets. Neither MoAb showed reactivity with erythrocytes, granulocytes, or resting and mitogen activated B and T lymphocytes.

ACTINOMYCIN D: SUPPRESSION OF RECOVERY IN X-IRRADIATED MAMMALIAN CELLS.

The lethal effect of two x-ray doses can be considerably enhanced if cultured cells are exposed to actinomycin D between doses. Net survival can be modified by temperature as well as actinomycin treatment. These effects are related to repair of sublethal damage and to cell kinetics between doses.