Lectin-binding characteristics of related high- and low-metastatic rat mammary adenocarcinoma cell lines.

Lectin-binding characteristics of a previously described highly metastatic variant (clone 4), derived in vivo from a poorly metastatic rat mammary adenocarcinoma (DMBA-8), have been investigated. of the lectins studied clone 4 cells, unlike the parent cells, bound Ulex europaeus agglutinin (UEA-1; specificity alpha-L-fucose) and peanut agglutinin (PNA; specificity D-galactose). These differences may be related to the greatly enhanced ability of clone 4 cells to form lung foci after intravenous injection.

Cellular and secreted tumor plasminogen activator: the effects of NaCl.

Plasminogen activator, secreted by metastatic tumor cells, was strongly inhibited in buffer or tissue culture medium containing physiological concentrations of NaCl. Intact cells, however, expressed strong activity under similar conditions. Thus, if plasminogen activator is involved in invasion and metastasis, the cellular activity, acting as an ectoenzyme, may be more important than secreted enzyme under physiological conditions.

Purification and characterization of an inhibitor of plasminogen activator released by rat mammary adenocarcinoma cells.

An inhibitor of plasminogen activator (PA) secreted by a tumorigenic, but non-metastatic, rat mammary adenocarcinoma cell line has been purified to apparent homogeneity and characterized. It strongly inhibited human urokinase, but was 100 times less potent in inhibiting bovine trypsin and had no effect on plasmin or thrombin. A secreted, urokinase-type PA (Mr 48 000) and a cell-associated PA from a metastatic rat adenocarcinoma cell line were also strongly inhibited.

Enhanced plasminogen activator production by highly metastatic variant cell lines of a rat mammary adenocarcinoma.

Highly metastatic cell lines have been isolated from lung foci formed by the intravenous injection of large numbers (5 X 10(6)) of cells of a poorly metastatic rat mammary adenocarcinoma (DMBA-8). The metastatic variant lines were phenotypically different and, unlike the parent line, produced high levels of plasminogen activator (PA) separable into three major bands (MW 30,000, 48,000 and 83,000) on SDS-PAGE. It is suggested that PA may play a role in the enhanced metastatic ability of these cells.

An inhibitor of plasminogen activator produced by tumour cell fusion hybrids.

Expression of plasminogen activator (PA) activity may be an important factor in the ability of tumour cells to metastasize; however, not all metastatic cells produce detectable PA activity. Conditioned culture media from revertant metastatic clones of cells derived by fusion of metastatic and non-metastatic rat mammary adenocarcinoma cells were found to contain a potent inhibitor of PA. This inhibited thrombin, human urokinase (UK) and tumour-derived PA, but not plasmin or trypsin.

Characterisation of rat tumour cell hybrids: procoagulant and fibrinolytic activities.

The formation of lung colonies after i.v. injection of highly metastatic rat mammary adenocarcinoma cells (MAT 13762) was greatly reduced by concurrent treatment of rats with heparin.

Studies on rat mammary adenocarcinomas: a model for metastasis.

Studies carried out by the authors on the rat mammary adenocarcinoma cell lines MAT 13762 and DMBA-8 are summarized. A series of variants and somatic cell hybrids have been prepared and partially characterized in terms of phenotypic properties which may correlate with metastatic potential. These include measurement of in vitro migration, lectin binding properties, expression of procoagulant activity and shedding of cell surface components.

Studies on migration inhibitory factors of non-lymphoid origin.

A large number of mouse fibrosarcoma and adult guinea pig fibroblast cultures were examined for their ability to produce migration inhibitory activity. In most cases culture supernatants were found to inhibit macrophage migration, in a dose-dependent manner. Toxicity of the tested material could be excluded by: a) experiments using colchicine as a stimulator of macrophage migration and, b) examination of the effect of test materials on macrophage monolayer cultures.

Effect of an iron-chelating agent on lymphocyte proliferation.

The effect of the iron-chelating agent desferrioxamine on lymphocyte proliferation has been studied. Desferrioxamine at concentrations of 15 microM totally inhibited the proliferation of Concanavalin A-stimulated lymphocytes, whereas iron-saturated desferrioxamine was ineffective. Other metal salts, however, had little or no effect on the inhibition induced by this drug.

Spontaneous capillary tube migration of metastatic rat mammary adenocarcinoma cells.

The spontaneous capillary tube migration of metastatic MAT 13762 rat mammary adenocarcinoma cells has been measured and compared with that of a non-metastatic variant, TGR. MAT 13762 cells migrated to a greater extent in the presence than in the absence of serum, and in both cases migration areas were considerably greater than for TGR cells. Different clones of hybrids, formed by fusing metastatic and non-metastatic variants, showed migration areas ranging from those of the metastatic to those of the non-metastatic parent cells.

The use of cell fusion to analyse factors involved in tumour cell metastasis.

Cell fusion has been used to study some of the factors involved in the process of metastasis. Highly metastatic rat mammary adenocarcinoma cells were fused with various non-metastatic cells and the hybrid clones isolated. These were then tested for their metastatic potential either by injecting the cells intravenously and measuring lung colony formation or by injecting the cells subcutaneously and measuring their ability to form lymphatic metastases.

Phorbol myristate acetate-induced macrophage aggregation.

Phorbol myristate acetate (PMA) at nanomole concentrations induces a rapid aggregation of guinea pig macrophages. This aggregation is dependent on extracellular Mg2+ (but not Ca2+) for its development. Additionally, it is inhibited by some agents which also inhibit aggregation induced by lymphokines and the ionophore A23187.

Diagnosis of penicillin allergy. An evaluation of the leucocyte aggregation test in man.

A study was made to establish the value of the leucocyte aggregation test (LAT) in drug allergy using penicillin antigen. The antigen-induced human peripheral blood leucocyte aggregation was measured quantitatively. The results obtained have been compared with the leucocyte migration inhibition test (LMIT) in patients with or without delayed penicillin allergy.

Comparison of mycobacterial granulomas in guinea-pig lymph nodes.

A study was made of mycobacterial-induced granulomas in guinea-pig lymph nodes. Live BCG (Pasteur) induced a granuloma containing epithelioid cells while Cobalt irradiated Mycobacterium leprae induced a granuloma comprised of phagocytic macrophages. The granulomas were quantitated by measurement of lymph node weight and the areas of infiltration in histological sections.

Lymphokine-induced neutrophil aggregation.

Lymphokine (LK) preparations, containing macrophage aggregating activity, also aggregated purified neutrophils, but not blood mononuclear cells or erythrocytes. Additionally, aggregation of blood leucocytes (containing 50%-70% neutrophils), from sensitized guinea-pigs, could be induced by culture of these cells with antigen, in a direct aggregation assay. Optimal measurement of direct aggregation was at 6 hr, whereas soluble neutrophil aggregating activity was produced by blood mononuclear cell cultures continuously for at least 24 hr.

Macrophage aggregation factor: some properties.

The lymphokine activity, macrophage aggregation factor (MAgF) has been investigated further. Activity was consistently found in 24 hr test, but not control, spleen cell culture supernatants. This was higher after dialysis against water, than in the original culture supernatants.

Lymphokine-induced macrophage aggregation: studies on the involvement of Mg2+.

The divalent cation requirements of lymphokine (LK)-induced macrophage aggregation have been investigated using a quantitative assay. It has been shown that LK-induced aggregation is dependent on exogenous Mg2+ but not Ca2+. By contrast, aggregation induced ty the ionophore A23187 is dependent on exogenous Ca2+ and Mg2+.

Lymphokine-induced macrophage aggregation: involvement of cyclic-GMP and microtubules.

Human lymphokine (LK) is known to induce guinea pig macrophage aggregation. This effect can be quantitatively measured with a Born modified platelet aggregometer. This method has been well correlated with the state of delayed hypersensitivity.

Concanavalin A-induced macrophage aggregating factor.

The production of the lymphokine activity macrophage aggregating factor (MAgF) by Concanavalin A (Con A)-pulsed guinea-pig spleen cells has been investigated. The following observations have been made: (1) MAgF can be assayed quantitatively by measuring the light absorbance of peritoneal exudate cells (PEC) using a spectrophotometer, rather than the previously used Born platelet aggregometer; (2) both Con A and antigen-induced MAgF elute from Sephadex G-200 over the 30,000-70,000 m wt range; (3) Con A-pulsed spleen cells generate supernatants which can be assayed directly for MAgF. Inhibitor studies with alpha-methyl-D-mannoside show that the observed PEC aggregation is due to MAgF and not to residual Con A, which also aggregates these cells.

Experimental mycobacterial granulomas in guinea pig lymph nodes: ultrastructural observations.

A systematic ultrastructural study has been performed of the mononuclear phagocytes in granulomas induced by different types of mycobacteria, e.g. live BCG (Pasteur), irradiated M.

Absorption of macrophage aggregating factor by guinea-pig peritoneal exudate cells.

Lymphokine (LK)-induced aggregation of peritoneal exudate cells (PEC) has been measured using a quantitative technique. Aggregating activity could be removed from LK preparations by absorption of these with PEC and, in addition, the absorbing PEC, on further incubation themselves aggregated. Absorption of aggregating activity to PEC was rapid, being easily measurable at between 2-5 and 10 min although it was difficult to demonstrate at 30 min.

Lymphokine-induced Macrophage aggregation: the possible role of cyclic nucleotides.

The possible role of cyclic nucleotides in guinea pig macrophage aggregation, induced by human lymphokine (LK) has been investigated. Small increases were found in guanosine 3'5'-cyclic monophosphate (cGMP), but not adenosine 3'5'-cyclic monophosphate (cAMP), levels of lymphokine aggregated macrophages. Addition of exogenous dibutyryl (DB) cAMP, L-isoproterenol, or theophylline did not induce macrophage aggregation.

Ultrastructure of cells of the mononuclear-phagocyte series (MPS) across the leprosy spectrum.

A systematic ultrastructural study of cells of the MPS across the spectrum of leprosy has been carried out. Graded changes in macrophage ultrastructure from the lepromatous to the tuberculoid poles have been shown. Mycobacteria-filled macrophages in lepromatous leprosy are characterised by long cell processes, whereas in borderline tuberculoid leprosy these cells have a rounded appearance and are mainly characterised by numerous intracellular vacuoles.

Studies on lymphokine-induced macrophage aggregation. Specificity and quantitative aspects.

A method for the quantitative measurement of macrophage aggregation by lymphokine preparations has been described previously. This involved the continuous measurement of the light absorbance of stirred suspensions of guinea pig peritoneal exudate cells (PEC). We now show that using a modified method, both aggregation of normal PEC, induced by preformed lymphokine, and direct aggregation of sensitized PEC with specific antigen can be measured.