Journal of the Reticuloendothelial Society最新文献

Highly purified (97-99%), human peripheral blood monocytes, isolated by an EDTA-reversible adherence procedure, exhibit spontaneous killing in a rapid, 51Cr-release assay. Using the single cell conjugate/dextran assay, we have quantitatively determined select requirements for the adhesion of monocytes to neoplastic target cells. Monocytes expressed a broad binding capacity to a wide spectrum of nonadherent tumor cell lines, while binding at minimal levels to nontumor target cells. Binding of monocytes to K562 tumor cells is an extremely rapid event, reaching saturation levels within 5 min after cosedimentation. The binding of monocytes to K562 targets was reduced by low temperatures and pretreatment with metabolic inhibitors. Pretreatment of monocytes with cytoskeletal-disruptive drugs significantly reduced binding. Monocytes were shown to exhibit a specific, Mg2+-dependent, Ca2+-independent mechanism in their binding to K562 cells. Subsequent to binding, Ca2+ was required for monocyte-mediated target cell lysis to proceed. The binding of tumor cells by monocytes was studied morphologically using transmission (TEM) and scanning electron microscopic (SEM) techniques. It was observed that binding was achieved initially through complex, surface membrane interdigitations from apposing effector--target cells and progressed to stable conjugates, which were characterized by contact regions consisting of large expanses of closely apposed surface membranes. The application of the single cell conjugate/dextran assay to assess monocyte-binding requirements and the morphological characterization of the monocyte--target cell conjugation process may help in clarifying the mechanisms of monocyte-mediated tumor cell lysis.

The proliferation of human bone marrow cells was studied in a liquid culture system without colony-stimulating factor. Bone marrow cells suspended in medium containing horse serum and fetal calf serum were incubated in the Teflon culture bag. During the first week there was an increase in the number of blast cells and early cells of the granulocytic series, both of which showed a high 3H-thymidine labeling index. The total number of mononuclear phagocytes increased during the first two weeks of culture. A number of characteristics of the cultured cells (alpha-naphthyl butyrate esterase, N-acetyl-DL-alanyl alpha-naphthyl esterase, Fc receptors, and phagocytosis) were determined. It was not feasible to recognize promonocytes and monoblasts with light microscopy, but with electron microscopy and the use of peroxidatic activity as marker, monoblasts and promonocytes were identified. The monoblast is a round cell with a few surface microextensions, a large nucleus, and few cytoplasmic granules. The nuclear envelope, the rough endoplasmic reticulum, and the granules show peroxidatic activity.

Human peripheral blood monocytes (PBM) and bronchoalveolar macrophages (BAM) were tested for cytotoxicity toward a cultured human lung tumor cell line, A549, using a 75Se-methionine post-labelling assay. Cytotoxicity of increasing numbers of PBM plateaud at an effector cell (E):target cell (T) ratio of 3:1. In contrast, BAM cytotoxicity was significantly lower than that of PBM at low E:T ratios but increased in a dose-dependent manner approaching 100% at an E:T ratio of 20:1, this increased cytotoxicity being due to cytolysis. PBM cytotoxicity appeared to be suppressed at least partly by a factor(s) liberated by PBM themselves. The different nature of the two effector cell populations' cytotoxic dose response curves and kinetic studies, and the inability of lipopolysaccharide to stimulate a level of PBM cytotoxicity attainable by BAM, suggested that the mechanism of cytotoxicity of the two cell populations differed or that BAM were more activated than PBM, or both.

The in vitro function of pulmonary alveolar macrophages (PAM) was compared for human smokers and nonsmokers. Initial studies demonstrated the feasibility of shipping lavaged cells on ice with storage up to 6 hr. Comparative studies were performed to evaluate ideal culture conditions including media composition, preincubation period, and phagocytic variables. Smokers had a six-fold enhancement in lavagable macrophages compared to nonsmokers. Macrophages from smokers demonstrated a decreased phagocytic capability compared to nonsmokers. The effects of cigarette smoking on phagocytosis were observed over a wide range of challenge periods using either fetal or newborn bovine serum (FBS or NBS). Regardless of smoking history, enhanced phagocytosis was observed with media containing NBS compared to FBS. No effects on in vitro viability, attachment, or adherence were observed.

We have utilized electronic cell volume (ECV) and several fluorescent analogues of traditional macrophage markers in a flow cytometric characterization of macrophage heterogeneity. With this technique, various features of macrophage differentiation and activation can be determined on as few as 10,000 cells per assay. Quantitations of cell volume, phagocytosis, RNA, myeloperoxidase, acid phosphatase, and the ectoenzyme leucine aminopeptidase have been carried out on cultured human monocytes and peritoneal macrophages. Quantitations of the amount of a particular marker on a per cell basis, as well as population distributions, are of particular value in characterizing the heterogeneity in resident and inflammatory macrophages and the temporal relationships between different markers during macrophage activation and differentiation. This technique will facilitate a sophisticated analysis of monocyte-macrophage development by permitting the simultaneous analysis of a number of these features. In this way the interrelationships between different macrophage markers can be quantitated at the single cell level.

Whole mononuclear cells plated on surfaces coated with the polymer, poly (2-hydroxyethyl methacrylate) (poly-HEMA) produced significantly less C2 when compared to production by cells on tissue culture plastic dishes. The reduction in C2 production was dependent on the amount of poly-HEMA used to coat the dishes and was not due to nonspecific damage of the cells or effects of the poly-HEMA on the hemolytic activity of C2. T and B lymphocytes, but not monocytes, plated on tissue culture plastic produced a soluble factor that increased the production of C2 in freshly adherent monocytes. Lymphocytes plated on the poly-HEMA surface did not produce this soluble factor, which was termed surface-dependent factor (SDF). Whole mononuclear cells plated on poly-HEMA were able to respond to SDF by increasing C2 production by the same percentage as cells on the tissue culture plastic. This suggested that the primary basis for the decreased production of C2 by monocytes in the whole mononuclear cells plated on the poly-HEMA was decreased production of SDF by the lymphocytes. The effect of the poly-HEMA surface on C2 production was probably related to a generalized alteration in maturation of monocytes into macrophages, for SDF had the same type of effect on beta-glucosaminidase levels in monocytes as seen with C2, except that the magnitude of the effect was less. These studies suggest that interaction of lymphocytes with surfaces may modulate the function of the lymphocytes. In addition, interaction of lymphocytes with surfaces and the production of SDF in vivo may be responsible for enhancing maturation of monocytes in tissues.

The present studies show that rat Kupffer cells are capable of both suppression and enhancement of mitogen responses. Studies were conducted using the T-cell mitogens concanavalin A and phytohemmaglutinin, as well as the rat B-cell mitogen Mycoplasma neurolyticum. Whereas Kupffer cell concentrations of 1 X 10(5)/well significantly suppressed the T- and B-mitogen response of both spleen nonadherent and peripheral blood lymphocytes, enhancement was restricted to the T-cell mitogen responses. No tissue-related differences were found in the suppression. However, both tissue differences and age-related changes were observed with enhancement. Age-related changes in the Kupffer cell resulted in a decreased enhancement of the proliferative response of spleen to concanavalin A and an increased response of peripheral blood lymphocytes.

Purified Kupffer cells were obtained by centrifugal elutriation of sinusoidal cells isolated by pronase treatment of the rat liver. The endocytosis of radioactively labeled heat-aggregated colloidal albumin (CA 125I) was investigated in maintenance cultures of the purified Kupffer cells. The endocytic capacity of the cells was studied during 4 days of culture. Maximum uptake was observed after 24 hr of culture, with a gradual decline during the following days. When the uptake was measured after incubation with increasing concentrations of CA 125I, a saturation effect was observed. This finding and the observed high rate of uptake are strong indications that receptor sites on the cell membrane are involved in the mechanism of endocytosis. The uptake of CA 125I by Kupffer cells was inhibited by the metabolic inhibitors fluoride and antimycin A, indicating that endocytosis of CA 125I is dependent on energy derived from both glycolysis and mitochondrial respiration. The mechanism of internalization may also require the action of microfilaments as well as intact microtubules, since both cytochalasin B and colchicine inhibited the uptake of CA 125I. The intracellular degradation of CA 125I by Kupffer cells was strongly inhibited by chloroquine but not by colchicine. The degradation of ingested CA 125I occurred within the Kupffer cell lysosomes.

In this paper we describe for the first time cellular contacts of modified erythrocytes (RBC) and tumor cells with Kupffer cells in the perfused liver. The fate of tumor cells and modified erythrocytes, injected via the portal vein into the perfused rat liver was followed by intravital microscopy. In this system phagocytic cells in the liver were labeled with latex particles. Both xenogeneic erythrocytes and tumor cells (leukemia L5222) were trapped by Kupffer cells forming rosettes, whereas leukemia cells were also trapped by endothelial cells.