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J Hammerstrøm

Publications and source records attributed to J Hammerstrøm.

43 records · Page 3Linked to original sources
PubMed1980

In vitro response to Corynebacterium parvum of human effusion lymphocytes isolated from patients with malignant and benign disease.

Non-adherent effusion cells (EC), mostly lymphocytes, were isolated from the pleural effusions of 8 patients with malignant and 7 patients with benign disease. Corynebacterium parvum (Cp) induced increased methyl-3H-thymidine (methyl-3H-TdR) incorporation in EC cultures, but the response was lower than that usually found with autologous or allogeneic normal human blood lymphocytes. Experiments with highly purified effusion lymphocytes indicated that the response to CP was influenced by the presence of adherent cells, probably macrophages. Normal human monocytes incubated in vitro with supernatants of unstimulated EC cultures expressed slightly increased ability to suppress methyl-3H-TdR-incorporation in a human tumour cell line. Supernatants of Cp-stimulated EC induced a further increase in monocyte-mediated cytostatic activity. Cell-free effusion fluid from 8 patients were largely inactive when tested for induction of monocyte-mediated cytostatic activity in the same system, and the effusion fluid reduced monocyte methyl-3H-TdR-incorporation in vitro. Thus, Cp seems to be able to induce DNA-synthesis and release of mononuclear phagocyte-activating lymphokines in human effusion lymphocytes.

Cell Division↗
PubMed1979

Human monocyte-mediated cytotoxicity to K-562 cells: activation by lymphokines.

Human monocytes purified by adherence and prolonged in vitro monolayer culture were activated by supernatants of autologous lymphocytes stimulated with live bacillus Calmette-Guérin or killed Corynebacterium parvum. Activated monocytes expressed increased ability to lyse K-562 cells prelabelled with methyl-3H-thymidine in a 48 h assay. Activation could be detected at a 1:64 dilution of lymphokine supernatants. Target cell killing by activated monocytes was strongly influenced by the density of the monocyte monolayer. Monocytes at an intermediate stage of in vitro differentiation seemed to be most response to lymphokine activation. Morphological studies indicated that a considerable number of K-562 cells attach firmly to monocytes. The monocyte-mediated lysis of K-562 seems to be extracellular, as phagocytosis was not observed. Freshly isolated adherent blood mononuclear cells (greater than 90% monocytes) were strongly cytostatic to K-562 cells, as determined by inhibition of methyl-3H-thymidine uptake. Considerable cytolytic activity was also found with freshly isolated adherent cells, strong enhancement being produced by performing the assay in the presence of newborn calf serum, as opposed to human AB serum.

Cell Differentiation↗
PubMed1979

Human macrophage differentiation in vivo and in vitro. A comparison of human peritoneal macrophages and monocytes.

Human mononuclear phagocytes isolated from venous blood or sterile peritoneal exudate were cultured in an in vitro system known to induce differentiation of monocytes to macrophages. Morphological and functional studies were performed at different stages of in vitro differentiation, in order to compare the two macrophage populations. Freshly-isolated human peritoneal macrophages (PEC), which are presumed to represent monocytes which have differentiated in vivo in the peritoneal exudate for 1--2 days, showed several signs of increased effector cell function, as compared to the relatively immature blood monocytes. Cell adherence after phagocytosis, ability to degrade ingested 125I-labelled Candida albicans, and ability to suppress DNA-synthesis in a target cell line of human origin, were all found to be greater in the peritoneal cells in early culture. During in vitro differentiation in this system, both PEC and monocytes developed remarkable morphological and functional changes. Cell size and granule content increased considerably. Cell function, measured as phagocytic, digestive and cytostatic ability, increased for both macrophage populations. The differences between the two cell populations in early culture suggest that the functional and morphological changes induced by in vivo differentiation in peritoneal exudate involve changes of the same kind as those induced by in vitro differentiation in our system. The lodging of mononuclear phagocytes in sterile peritoneal exudate does not seem to impair the capacity for further differentiation to any great extent.

Adult↗
PubMed1979

Direct effects of Corynebacterium parvum and BCG on human monocyte-mediated tumour cell cytostasis in vitro.

Four strains of Corynebacterium parvum (Cp) and BCG induced low levels of cytostatic ability to a human tumour cell line in human monocytes when added directly to conventional monocyte cultures. The cytostatic ability induced by mediators from autologous lymphocytes stimulated with the same agents was greater than that produced by direct addition to monocytes. BCG was more efficient in stimulating lymphocyte DNA-synthesis and lymphokine release than any of the Cp strains tested. In order to test the influence of contaminating adherent lymphocytes on the direct induction of cytostasis, monocyte cultures of greater than 99.9% purity were prepared by adherence purification. Cp induced low levels of cytostatic ability in such highly purified monocytes when added directly to the monocytes. Addition of BCG and Candida albicans had an adverse effect on the cytostatic ability of purified monocytes. A morphological study of Cp interaction with purified monocytes was performed. Cp, but not BCG, would seem to be able to induce low levels of cytostatic ability in human monocytes without lympohcyte cooperation. Human monocyte activation by the more effective lymphokine pathway is more efficiently triggered in vitro by BCG than by Cp.

Candida albicans↗
PubMed1979

In vitro influence of endotoxin on human mononuclear phagocyte structure and function. 1. Depression of protein synthesis, phagocytosis of Candida albicans and induction of cytostatic activity.

The effect of E. coli endotoxin (LPS) on human monocytes and peritoneal macrophages (PEC) during in vitro differentiation was studied. Short-term (less than 24 hours) exposure to LPS in concentrations up to 50 microgram/ml did not affect monocyte survival or 51Cr-release, but concentrations of 10 microgram/ml or more reduced monocyte survival when LPS exposure was prolonged to 72 h. Undifferentiated monocytes seemed to be sensitive to this effect. Monocyte and PEC protein synthesis was reduced by nontoxic LPS concentrations in both undifferentiated and differentiated cells. LPS exposure reduced monocyte ingestion and degradation of 125I-labelled Candida albicans, dependent on time and dosage. The induction of monocyte- and PEC-mediated cytoststic activity to tumour cells induced by prolonged in vitro culture was also impaired by LPS. The morphological alterations induced in mononuclear phagocytes by LPS included a changes distribution of cells in the monolayer, changes in membrane structure and apparent reduction of lysosomes. LPS thus interferes adversely with several aspects of human mononuclear phagocyte in vitro differentiation.

Candida albicans↗
PubMed1979

In vitro influence of endotoxin on human mononuclear phagocyte structure and function. 2. Enhancement of the expression of cytoststic and cytolytic activity of normal and lymphokine-activated monocytes.

The presence of non-toxic concentrations of E. coli endotoxin (LPS) during the in vitro interaction of normal human monocytes and a human tumour cell line (NHIK 3025) enhanced monocyte-mediated target cell cytostasis and cytolysis. Monocyte responsiveness to LPS was greatest at an intermediate stage of in vitro differentiation. The expression of cytostatic and cytolytic activity by human monocytes activated with mediators from Corynebacterium parvum-stimulated human lymphocytes was also enhanced by LPS. Lymphokine activation did not induce additional LPS responsiveness in the monocytes. Monocytes activated with lymphokines and subsequently deactivated by in vitro culture did not show any increase in LPS responsiveness. A soluble cytostatic factor, which is probably not cold thymidine, was released from monocytes exposed first to lymphokines and then to LPS. While LPS is ineffective as an induction signal of monocyte cytotoxicity to tumour cells in this system, it enhances the expression of cytotoxicity induced by prolonged in vitro culture or lymphokine activation.

Adult↗