Interaction of BCG-activated macrophages with neoplastic and noneoplastic cell lines in vitro: cinemicrographic analysis

An in vitro model for the lepromatous leprosy granuloma: fate of Mycobacterium leprae from target macrophages after interaction with normal and activated effector macrophages

The lepromatous leprosy granuloma is a dynamic entity requiring a steady influx of macrophages (Mphi) for its maintenance. We have developed an in vitro model to study the fate of Mycobacterium leprae in a LL lesion, with and without immunotherapeutic intervention. Target cells, consisting of granuloma Mphi harvested from the footpads of M. leprae-infected athymic nu/nu mice, were cocultured with normal or IFN-gamma-activated (ACT) effector Mphi. The bacilli were recovered and assessed for viability by radiorespirometry. M. leprae recovered from target Mphi possessed high metabolic activity, indicating a viable state in this uncultivable organism. M. leprae recovered from target Mphi incubated with normal effector Mphi exhibited significantly higher metabolism. In contrast, bacilli recovered from target Mphi cocultured with ACT effector Mphi displayed a markedly decreased metabolic activity. Inhibition by ACT Mphi required an E:T ratio of at least 5:1, a coculture incubation period of 3-5 days, and the production of reactive nitrogen intermediates, but not reactive oxygen intermediates. Neither IFN-gamma nor TNF-alpha were required during the cocultivation period. However, cell-to-cell contact between the target and effector Mphi was necessary for augmentation of M. leprae metabolism by normal effector Mphi as well as for inhibition of M. leprae by ACT effector Mphi. Conventional fluorescence microscopy and confocal fluorescence microscopy revealed that the bacilli from the target Mphi were acquired by the effector Mphi. Thus, the state of Mphi infiltrating the granuloma may markedly affect the viability of M. leprae residing in Mphi in the lepromatous lesion.

The role of macrophages in antitumor defense of patients with ovarian cancer

Macrophages have diverse effects on tumor biology, including neovascularization, growth rate, and stroma formation. Tumor-associated macrophages (TAMs) represent a major subpopulation of the mononuclear leukocytes present in malignant ascites of ovarian cancer patients. TAMs appear to participate in the immunologic antitumor defense mechanism through cytotoxic activities, such as direct cellular cytotoxicity and the release of cytokines, and may represent key targets for a variety of therapeutic interventions.

Fibroblast growth in vitro suppressed by LPS-activated macrophages. Reversal of suppression by hydrocortisone

Activated macrophages are among the major constituents of the periapical granuloma. Their state of activation may persist for long periods after the local irritant is removed and may delay resolution and repair of the lesion. The effect of activated macrophages on fibroblast growth was studied in vitro. Circular fibroblast colonies were formed using a drop containing 7.5 x 10(5) murine dermal fibroblasts and allowed to grow for 7 days. When peritoneal exudate macrophages were added (0.5-3.0 x 10(6) cells/dish) and activated in vitro by LPS (1 microgram/ml), the fibroblast colony's growth was suppressed. LPS alone, at the concentration used, had no effect on the fibroblast growth. Hydrocortisone (> or = 10(-7) M) totally reversed the suppression, when added either simultaneously with or 6, 24, or 48 h after the LPS. The efficacy of late hydrocortisone treatment suggests that its effect was through prevention of the expression of the LPS activation of the macrophages. These findings may provide a possible clue to a pharmacological modulation of the healing processes that occur in the periapical lesion once its infective source had been eliminated.

Effect of Escherichia coli L-form cytoplasmic membranes on the interaction between macrophages and Lewis lung carcinoma cells: scanning electron microscopy

Scanning electron microscopy (SEM) investigations on the interactions between peritoneal macrophages from Lewis lung carcinoma (LLC)-bearing mice and LLC tumour cells during 21 days after tumour implantation were carried out. The action of lipopolysaccharide (LPS)-containing cytoplasmic membranes (CM), from the stable protoplast type L-form of Escherichia coli, on the activity of in vitro phagocytosis was studied; CM induced a continuous increase in macrophage numbers. Activation of macrophage surfaces in healthy and tumour-bearing mice was established. Lamelipods, pseudopods and migration fringes 14 days after CM application were seen. Crater-like cavities deeply in the macrophage cells as well as adherent or prominent engulfed tumour cells within macrophages were observed during in vitro interaction with LLC cells. Macrophages from tumour-bearing mice without CM treatment showed less activation evaluated by SEM during earlier stages of tumour growth. The SEM investigation proved the temporary stimulating effect of E. coli L-form CM on the cell surface activation of peritoneal macrophages in healthy and LLC-bearing mice.

Neuronal toxicity by macrophages in mixed brain cell culture is augmented by antineuronal IgG and dependent upon nitric oxide synthesis

We used mixed brain cell cultures derived from dissociated neonatal rat cerebella to study interactions between mononuclear phagocytes and brain cells under various conditions. We found that activated macrophages were capable of selectively killing neurons, leaving other cells undisturbed. Moreover, this activity was dependent upon nitric oxide production and, to a weaker extent, upon the NMDA receptor but not upon tumor necrosis factor. Macrophage-mediated neuronolysis was augmented by one of two anti-neuronal antibodies studied.

Randomized phase III trial of chemoimmunotherapy in patients with previously untreated stages III and IV suboptimal disease ovarian cancer: a Southwest Oncology Group Study

Between 1979 and 1984, 185 fully evaluable patients with stage III or IV epithelial type ovarian cancer and suboptimal surgical resections were randomly assigned to treatment with doxorubicin + cyclophosphamide + BCG (DC + BCG) vs doxorubicin + cyclophosphamide + cisplatin (DCP) vs. doxorubicin + cyclophosphamide + cisplatin + BCG (DCP + BCG). Patients with measurable disease (119) were analyzed separately from those with nonmeasurable disease (66). In measurable disease patients the overall clinical complete plus partial response rates for DC + BCG, DCP, and DCP + BCG-treated patients were 36, 57, and 59%, respectively. Although there were no significant patient characteristic differences between the DCP and DCP + BCG treatment groups, the addition of cisplatin to the DC + BCG regimen resulted in significantly prolonged response (P less than 0.03) and survival (P less than 0.002) durations. To the contrary, the addition of BCG to the DCP regimen did not improve objective response rates or response or survival durations. For patients with nonmeasurable, suboptimal disease there were no significant differences between the three treatments with respect to response or survival parameters; however, patients in this disease category fared generally better than those with clinically measurable disease. We conclude that cisplatin adds significantly to the efficacy of DC + BCG, but BCG does not add to the efficacy of DCP in patients with measurable, stage III or IV disease.

Human monocytes selectively bind to cells expressing the tumorigenic phenotype

The characteristics of the binding of human monocytes to tumor cells were studied by a newly developed microassay. First, we determined the kinetics and optimal conditions of the binding. Monocytes recognized and bound to tumor cells very rapidly within 10-20 min of cellular interaction. Binding was also more efficient at 37 degrees C suggesting that active metabolism of monocytes is required. Second, we determined that selective binding of monocytes to cells with tumorigenic phenotypes occurs. For this purpose, lymphocytic leukemia cell lines versus normal lymphocytes, and tumorigenic versus nontumorigenic hybrids from the same parental lines were compared as the targets of the binding assay. In both cases, neoplastic cells were selectively bound by monocytes. Although tumor cells were bound rapidly and selectively by monocytes, initial recognition and binding did not necessarily lead to subsequent tumor cell lysis. This is based on the observation that some tumorigenic parental and hybrid lines were avidly bound by monocytes yet not subsequently killed in a cytotoxicity assay.

Correlation of susceptibility and cytostatic factor-inducing activity of tumour cells to peritoneal macrophages. The role of concanavalin A-binding glycopeptides extracted from the tumour cell surface

L929, 3T12-3, B16, 3LL, and YAC1 cells with cytostatic factor (CF)-inducing activity from Lactobacillus casei-elicited murine peritoneal macrophages (LCEPM) were susceptible to the cytostatic activity of LCEPM and to LCEPM-produced CF, but L1210, P388D1, and Colon 26 cells, which have no CF-inducing activity, were resistant to that of LCEPM and and to the CF. The resistance of P815 cells to that of LCEPM was stronger than that of 3T12-3 cells, but the CF-inducing activity of P815 cells was about 50% weaker than that of 3T12-3 cells. Release of CF from LCEPM was also caused by heat-killed (100 degrees C, 10 min) 3T12-3 or P815 cells, and this release was inhibited by D-mannose. The CF-inducing activity of heat-killed 3T12-3 or P815 cells was reduced by mild trypsin digestion (37 degrees C for 10 min). A D-mannose-containing glycopeptide or glycoprotein (GP) was separated from 3T12-3 or P815 cells by concanavalin A (Con A) or wheat germ agglutinin (WGA) affinity chromatography. The CF were released from LCEPM by stimulation with the Con A-binding GP of the tumour cells, but the WGA-binding GP had little activity. It is suggested that tumour cells with CF-inducing activity may be susceptible to the cytostatic activity of LCEPM, and those without CF-inducing activity may be resistant to the cytostatic activity of LCEPM and the release of CF from activated macrophages may be caused by the Con A-binding GP of the tumour cell surface.

Murine cytotoxic activated macrophages inhibit aconitase in tumor cells. Inhibition involves the iron-sulfur prosthetic group and is reversible

Previous studies show that cytotoxic activated macrophages cause inhibition of DNA synthesis, inhibition of mitochondrial respiration, and loss of intracellular iron from tumor cells. Here we examine aconitase, a citric acid cycle enzyme with a catalytically active iron-sulfur cluster, to determine if iron-sulfur clusters are targets for activated macrophage-induced iron removal. Results show that aconitase activity declines dramatically in target cells after 4 h of co-cultivation with activated macrophages. Aconitase inhibition occurs simultaneously with arrest of DNA synthesis, another early activated macrophage-induced metabolic change in target cells. Dithionite partially prevents activated macrophage induced aconitase inhibition. Furthermore, incubation of injured target cells in medium supplemented with ferrous ion plus a reducing agent causes near-complete reconstitution of aconitase activity. The results show that removal of a labile iron atom from the [4Fe-4S] cluster, by a cytotoxic activated macrophage-mediated mechanism, is causally related to aconitase inhibition.

Suppression of fibroblast proliferation by activated macrophages: involvement of H2O2 and a non-prostaglandin E product of the cyclooxygenase pathway

Macrophages are considered promoters of fibroblast proliferation; however, suppression by activated macrophages may outweigh this effect. Activated murine peritoneal macrophages obtained by in vivo exposure to C. parvum or by in vitro LPS-activation of thioglycollate-induced macrophages, were tested for their effect on normal syngeneic dermal fibroblasts. C. parvum-activated macrophages, but not resident peritoneal macrophages suppressed fibroblast proliferation. Similarly, macrophages activated in vitro by LPS, but not those unexposed to LPS, suppressed fibroblast proliferation. Catalase partially protected fibroblasts from suppression by either activated macrophage population, suggesting involvement of H2O2 in the suppression. The effect of cyclooxygenase inhibitors on the suppression was also tested. Indomethacin, acetylsalicyclic acid, or eicosatetraynoic acid, all partially protected the fibroblasts from macrophage-mediated suppression. Prostaglandins E2, E1, and F2 alpha, added exogenously at concentrations as high as 10(-6) M, failed to suppress the proliferation of the fibroblasts. These findings suggest that a non-prostaglandin product of the cyclooxygenase pathway is involved in macrophage-mediated suppression of fibroblast proliferation.

Disruption of oligosaccharide processing in murine tumor cells inhibits their susceptibility to lysis by activated mouse macrophages

The components of tumor cell surfaces that participate in the recognition and lysis of these cells by activated macrophages have not been identified. One plausible hypothesis is that these components are specific carbohydrate structures. As an initial test of this hypothesis, I have made use of the oligosaccharide processing inhibitors 1-deoxynojirimycin (dNM) and 1-deoxymannojirimycin (dMM). dNM is an inhibitor of the glucosidases involved in the initial steps of oligosaccharide processing. dMM inhibits mannosidase I. P815 cells incubated in the presence of 1-2 mM dNM for 24 hr synthesized mature glycoproteins that contained glucosylated high-mannose asparagine-linked oligosaccharides instead of complex forms. The glucosylated oligosaccharides were present in trypsin digests of the cell surface. The dNM treatment resulted in a diminution in the amount of surface galactose residues as evidenced by neuraminidase/galactose oxidase/NaB3H4 labeling of surface glycopeptides. It did not, however, inhibit protein synthesis or alter the surface polypeptide profile of the tumor cells. P815 and R1- cells incubated in the presence of 1-3 mM dNM for 24 hr were considerably less sensitive to lysis by interferon-gamma-activated macrophages than were cells incubated in control medium. At a dNM concentration of 3 mM, a 71% inhibition of P815 cell lysis was observed. Similarly, P815 and R1- cells incubated in the presence of 2 mM dMM were also less sensitive to macrophage-mediated lysis than were control cells. The inhibitors did not affect cell viability, growth, or gross morphology. These observations suggest that complex asparagine-linked oligosaccharides on tumor cell surfaces may participate in recognition and lysis by activated macrophages.

Activated macrophages demonstrate direct cytotoxicity, antibody-dependent cellular cytotoxicity, and enhanced binding of Naegleria fowleri amoebae

Macrophages activated in vivo by injection of Corynebacterium parvum or bacillus Calmette-Guérin caused direct cytolysis of the pathogenic free-living amoeba, Naegleria fowleri, in vitro. Amoebicidal activity was time and cell density-dependent but was not dependent on the presence of specific antibody. Antibody-dependent cellular cytotoxicity for amoebae was also expressed by activated macrophages. Resident and thioglycolate-elicited macrophages demonstrated low cytolytic activity under all conditions tested. From scanning electron microscopy it appears that the degree of target cell binding is directly related to the degree of cytolysis expressed by the macrophage populations. Cell-cell contact was required for cytolysis of amoebae by activated macrophages since cytolysis did not occur when contact was blocked by a porous filter. For each macrophage population, the levels of amoebicidal activity and tumoricidal activity were comparable.

A potential role for the extracellular matrix glycoprotein laminin in macrophage-tumor-cell interactions

Although cell surface molecules are thought to be involved in macrophage (MO)-tumor-cell recognition, the nature of these molecules remains unknown. In this study we have shown that the glycoprotein laminin may facilitate macrophage-tumor-cell binding. Macrophage binding to tumor cells was assessed by measuring the adherence of radiolabelled 3-MCA2 induced malignant fibrosarcoma cells to syngeneic peritoneal MOs. Addition of exogenous laminin promoted the binding of a weakly metastatic subline of these tumor cells by 31-68%. These weakly metastatic tumor cells express negligible endogenous cell-surface laminin but display specific cell-surface receptors for binding soluble laminin. Exogenous laminin promoted MO binding of these tumor cells whether it was present during the assay or whether the tumor cells were pretreated with the laminin. This increase in binding was blocked by anti-laminin antibody. In contrast, MO binding of a strongly metastatic variant of the same tumor was not enhanced by the addition of exogenous laminin. This highly malignant fibrosarcoma line already expressed endogenous cell-surface laminin. Since the MOs were found to specifically bind 125I-laminin, the interaction between laminin-bearing tumor cells and MOs may be mediated via a specific MO plasma membrane receptor. Thus, the expression of cell-surface laminin and its receptors on both tumor cells and MOs may provide a mechanism for promoting MO-tumor-cell binding.

Use of a P815-derived line with an amplified adenosine deaminase gene: an improved target for cellular cytotoxicity

We describe a cytotoxic T lymphocyte-mediated cytotoxicity assay in which the release of a cytoplasmic enzyme, adenosine deaminase (ADA), instead of the widely used radioactive chromium is a measure of target lysis. In this enzyme-release assay the target is a mastocytoma P815-derived cell line, noted P815 ADA++, isolated by applying a selection procedure devised to specifically amplify the ADA gene. Gene amplification in P815 ADA++ was indeed demonstrated. Routine measurement of ADA activity from numerous supernatants is performed using a specific and sensitive colorimetric assay. The use of 96-well microtiter plates as well as of an automatic Multiscan spectrophotometer makes this measurement rapid and convenient. We show that this ADA-release assay is significantly more sensitive than the classical chromium-release test because of its consistently lower (5 to 10-fold) spontaneous release in 4 h, short-term cytotoxicity experiments. We also found that it is especially suited for the rapid detection, by visual screening, of rare, active killer clones among large, heterogeneous cytotoxic T lymphocyte populations. The assay could easily be adapted to other tumor targets (EL4, YAC-1, K562) of common use in studies involving immune lysis; indeed, the procedure of amplifying the ADA gene used in the isolation of the P815 ADA++ hyperactive line may be generally applied to these targets.

Ultrastructural studies of the killing of schistosomula of Schistosoma mansoni by activated macrophages in vitro

Immunologically activated murine macrophages have been shown elsewhere to kill skin stage schistosomula of Schistosoma mansoni in vitro, in a manner analogous to the extracellular killing of tumour cell targets. In this study, the kinetics of the interaction between activated macrophages and larval targets and the resultant ultrastructural changes in parasite morphology that culminated in death have been analysed in detail. Unlike granulocyte-mediated schistosomular killing, macrophage-mediated cytotoxicity did not appear to be directed against the surface tissues of the parasite. Macrophages adhered only transiently following initiation of the cultures, yet changes in the subtegumental mitochondria and muscle cells of the larva were detected within the first hour of incubation. Progressive internal disorganisation followed rapidly, but the tegument and tegumental outer membrane remained intact, to form a 'shell' that maintained the general shape of the parasite. Such changes were recognised irrespective of whether the effector cell population comprised peritoneal macrophages activated by lymphokine treatment in vitro, or by infection with Mycobacterium bovis (strain BCG), or S. mansoni in vivo. That macrophages rather than contaminating granulocytes or lymphocytes, had mediated the observed damage was demonstrated by the use of a lymphokine treated macrophage cell line, IC-21. The observation that macrophage cytotoxicity is directed against internal organelles rather than the tegumental outer membrane of this multicellular target, may help to elucidate the general mechanism of extracellular killing by these cells.

Iron depletion: possible cause of tumor cell cytotoxicity induced by activated macrophages

The experiments reported here provide a possible molecular mechanism for the activated macrophage cytotoxic effect. Tumor cells that develop cytostasis and inhibition of mitochondrial respiration in response to cocultivation with activated macrophages release a significant fraction of their intracellular iron-59 content. Kinetic studies show that specific release of iron-59 from target cells begins 4-6 hours after initiating cocultivation which is the time point that inhibition of DNA synthesis is first detected. Treatment of tumor cells with metabolic inhibitors causing inhibition of respiration, protein synthesis, RNA synthesis, and DNA synthesis to a similar or greater extent than that caused by activated macrophages does not induce release of intracellular iron-59. It is significant that mitochondrial respiration and DNA replication, both strongly inhibited in target cells by activated macrophages, are metabolic pathways with enzymatic activity vulnerable to inhibition by depletion of intracellular iron.

Analysis of normal and abnormal amniotic fluid cells in vitro by cinemicrography

Time-lapse cinemicrography has been used to study cell behaviour and movement in long- and short-term amniotic fluid cultures from various types of fetus. These included several with a neural tube defect (9 anencephalics, 5 spina bifidas, 2 encephaloceles), 1 with an abdominal wall lesion (omphalocele) and 9 controls with no open lesion. In short-term (less than 3 days) amniotic fluid cultures from normal fetuses, non-adherent squamous cells dominate, but there is a small population of cells which, in the longer term (approximately 4 weeks), will form colonies of epithelioid and fibroblastic cells. In addition, there is a further group, called 'AF' by Hoehn et al. (1974), which have the ability to form syncitial strands and are often multinucleated; these cells seem to be trophoblastic in origin. In contrast to the controls, short-term anencephalic cultures contained many adherent cells; these were mainly latex-particle-phagocytosing macrophages and neural cells. In long-term cultures, the neural cells dominate and differentiate into a range of recognizable forms whose type and behaviour seem to depend on cell density, time in culture and extent of cell-cell contacts. In the spina bifida and encephalocele cultures, there were initially far fewer adherent cells than in the anencephalic ones, but, after approximately 2 weeks in vitro, a range of neural cell types could be recognized in addition to those seen in the controls. In the context of prenatal diagnosis, the presence of neural cells certainly indicates that the fetus has a NTD, but the difficulty of standardizing culture conditions implies that any differential diagnosis on the basis or morphology and movement will be difficult. If, as seems likely, the AF cells of Hoehn et al. (1974) are indeed trophoblastic, amniotic fluids from the second trimester may provide a useful source of these cells.

Macrophage-mediated cytostatic activity blocks lymphoblast cell cycle progression independently in both G1 phase and S phase

Recent work has shown that macrophage-mediated cytostatic activity inhibits cell cycle traverse in G1 and/or S phase of the cell cycle without affecting late S, G2, or M phases. The present report is directed at distinguishing between such cytostatic effects on G1 phase or S phase using the accumulation of DNA polymerase alpha as a marker of G1 to S phase transition. Quiescent lymphocytes stimulated with concanavalin A undergo a semisynchronous progression from G0 to G1 to S phase with a dramatic increase in DNA polymerase alpha activity between 20 and 30 hr after stimulation. This increase in enzyme activity was inhibited, as was the accumulation of DNA, when such cells were cocultured with activated murine peritoneal macrophages during this time interval. However, if mitogen-stimulated lymphocytes were enriched for S-phase cells by centrifugal elutriation and cocultured with activated macrophages for 4-6 hr, DNA synthesis was inhibited but the already elevated DNA-polymerase activity was unaffected. Similar results were obtained when a virally transformed lymphoma cell line was substituted as the target cell in this assay. These results show that both G1 and S phase of the cycle are inhibited and suggest that inhibition of progression through the different phases may be accomplished by at least two distinct mechanisms.

Evidence for granulocyte-mediated macrophage activation after C. parvum immunization

It has been previously demonstrated that at the peak of the peritoneal response to Corynebacterium parvum (Day 4), cytolytic macrophages can be characterized by the presence of intracellular bacteria. In the present study, the role of neutrophils in the activation of peritoneal macrophages by C. parvum was investigated. Inflammatory neutrophils isolated 5 hr after ip administration of C. parvum were transferred to normal, syngeneic mice and the peritoneal macrophages of recipients harvested 4 days later were tested for cytoxicity against HeLa cells. Neutrophils isolated from mice 5 hr after C. parvum immunization were effective in inducing cytolytic macrophages. Less than 100-fold as much bacteria was needed to induce comparable levels of cytotoxic activity when introduced inside granulocytes. Neutrophils obtained from mice 48 hr after C. parvum injection or mononuclear cells were not good macrophage activators. Viable neutrophils were not required as freeze-thawed cells were able to activate macrophages in recipient mice. The intracellular distribution of C. parvum changed dramatically with time. Initially almost all bacteria were found within neutrophils. By 24 hr, many macrophages contained either bacteria or granulocytes which had ingested C. parvum. Pyridine extracts of C. parvum, which do not activate peritoneal macrophages when injected directly into mice, did not induce neutrophils capable of activating macrophages. The residue of pyridine-extracted C. parvum did induce neutrophils that could activate macrophages when transferred. The results suggest that processing of the bacteria by inflammatory granulocytes may be an obligatory step in macrophage activation by this agent. The peak response occurred earlier than T-cell immunity is usually observed and it is suggested that direct activation of macrophages via ingestion of neutrophils may represent the earliest stage of macrophage activation by C. parvum.

Liposome induction or enhancement of macrophage-mediated cancer cell lysis

Liposomes of different composition have been used to modify macrophage-mediated destruction of syngeneic cancer cells through a modulation of membrane lipid content of macrophages and/or tumor cells. Dipalmitoylphosphatidylcholine (DPPC)1 liposomes induce cancer cell lysis by normal, non-tumoricidal, peritoneal macrophages and enhance tumor cell destruction by BCG-activated macrophages. This effect was produced by large and small unilamellar liposomes, which are in the 25,000 g supernatant of sonicated preparations. Addition of cholesterol or negative charges carried by dicetylphosphate supressed the effect of DPPC liposomes on macrophage-mediated cytolysis. Enhancement of macrophage-mediated tumor cell lysis was observed when both cancer cells and macrophages were incubated with DPPC liposomes, but not when macrophages and/or tumor cells were preincubated with liposomes prior to their coincubation. Liposomes did not promote the binding of the cancer cells to the macrophages. Liposomes could promote formation of phospholipid domains within the plasma membrane of both tumor cells and macrophages leading to the destruction of cancer cells through a temporary fusion with the macrophages.

Intermittent combination chemotherapy with or without bacillus Calmette-Guérin for treatment of acute lymphoblastic leukemia of childhood

Seventy-four children ranging in age from 6 months to 17.5 years with acute lymphoblastic leukemia newly diagnosed between 1976 and 1979 were entered on a study incorporating intermittent chemotherapy with or without the addition of bacillus Calmette-Guérin (BCG). The chemotherapy program consisted of induction with vincristine, dexamethasone, and intrathecal methotrexate, intensification with adriamycin and asparaginase, central nervous system treatment with cranial irradiation and intrathecal methotrexate, and continuation treatment with 5-day courses of combination chemotherapy administered every three weeks. The first phase of continuation therapy incorporated vincristine, adriamycin, 6-mercaptopurine, and dexamethasone. In the second phase, oral methotrexate was substituted for the adriamycin in non-T-cell patients; in T-cell patients, cytosine arabinoside or cyclophosphamide and methotrexate in alternating cycles were substituted for the adriamycin and asparaginase was added. Total duration of therapy was approximately 2.5 years. Connaught BCG was administered by Heaf gun on days 8 and 15 of each 3-week cycle for the first 8 months of treatment in approximately one-third of the patients. Actuarial disease-free survival with a median follow-up of 59 months shows no difference in outcome between the BCG and non-BCG poor-risk patients. However, there is an improvement in disease-free survival of BCG-treated good- and average-risk girls (P = 0.04). While patients were actively receiving BCG there was also a trend toward the development of fewer significant infections than when patients were not receiving BCG (P = 0.85). Toxicities from BCG administration included satellite rashes, local tenderness, lymphadenopathy, secondary infection, and residual scars. Overall disease-free survival by actuarial analysis is 60% at 6 years; for patients with unfavorable prognostic features it is 40%. In this trial the addition of BCG prolonged the disease-free survival of girls with good- and average-risk prognostic features and also may have decreased the susceptibility to infection while it was being administered. However, the benefit does not appear sufficient to warrant its routine use, especially in view of the toxicities encountered.

Human monocyte mediated cytotoxicity to K-562 cells: a freeze-fracture-, scanning- and thin section electron microscopic study

The structural features of "natural"human monocyte-mediated cytotoxicity towards K-562 leukemia cells in vitro have been examined. Human monocytes bound K-562 cells firmly and mediated a slow cytolysis of the leukemia cells. Monocyte binding of target cells was shown to be trypsin sensitive. Freeze-fracture and thin section electron microscopy revealed that effector and target cells were separated by a irregular space larger than 20 nm. There was no evidence for the involvement of specialized membrane junctions or organelle transfer between monocytes and target cells. Scanning electron microscopy revealed that K-562 cells bound to monocytes progressively lost their microvilli. This process started in the membrane areas close to the effector-target cell interaction. The results suggest that binding of target cells by monocytes followed by action of short-range soluble cytotoxic mediators may be the mechanism for the monocyte-mediated cytotoxicity towards K-562 cells.

Inhibition of nonspecific tumoricidal activity by activated macrophages with antiserum against a soluble cytotoxic factor

Mouse peritoneal macrophages activated for tumor cytotoxicity by any of several in vivo or in vitro treatments released a soluble cytotoxin into culture fluids only after exposure to small amounts of bacterial lipopolysaccharides. This cytotoxic factor was physicochemically similar to the cytotoxic factor (tumor necrosis factor) in sera of BCG-infected mice injected with lipopolysaccharide. A rabbit antiserum against partially purified serum cytotoxic factor also inhibited the activity of macrophage-derived cytotoxic factor. Of special interest was the observation that rabbit anti-cytotoxic factor inhibited the cytotoxic activity of macrophages both in the presence and in the absence of exogenously added lipopolysaccharide. Inhibition was not complete but was consistent in all experiments. Thus, cytotoxic factor was implicated as a possible effector molecule in the nonspecific tumoricidal activity of activated macrophages.

Binding of bacillus Calmette-Guérin-activated macrophages to tumor targets. Selective inhibition by membrane preparations from homologous and heterologous neoplastic cells

The binding of tumor cells by activated macrophages is an initial and necessary event in the cytolysis of these targets. The data here indicate that membrane preparations from RL sigma 1 leukemia targets, EL-4 lymphoma targets, and P815 mastocytoma targets each inhibited binding of its homologous target to bacillus Calmette-Guérin (BCG)-activated murine macrophages in a dose-dependent fashion. Similar amounts of membrane from lymphocytes did not alter binding of the three neoplastic target to BCG-macrophages. Membranes of the three targets also inhibited binding of the heterologous neoplastic targets. Inhibitory activity of membrane preparations from P815, EL-4, and RL sigma 1 targets could be adsorbed by incubation of limiting concentrations of the membrane preparations with BCG-activated macrophages but not with thioglycollate broth-elicited macrophages. Exposure of BCG macrophages to membrane preparations from RL sigma 1, FL-4, or P815 targets inhibited subsequent cytolysis of the three targets. Inhibitory activity was increased in preparations enriched for plasma membrane. The data suggest that binding of three murine, nonadherent neoplastic targets to BCG-activated murine macrophages is mediated, in part, by recognition structures present within the plasma membranes of the three targets.

Measurement of macrophage-mediated cytotoxicity against adherent and non-adherent target cells by release of 11 indium-oxine

This report describes the utilization of 111 indium-oxine chelate ([111In]Ox) for studies of macrophage-mediated cytotoxicity. [111In]Ox efficiently labeled both non-adherent and adherent tumor targets with no decrease in cell viability. Spontaneous release of intracellularly incorporated [111In]Ox was very slow (0.25-0.50%/h) from most targets, making isotope-release assays of at least 48 h feasible. In addition, released [111In]Ox was not reutilized. In contrast to its low spontaneous release from intact cells, incorporated [111In]Ox was rapidly released from tumor targets after interaction with activated macrophages. Levels of [111In]Ox released in response to cytolytic macrophages correlated well with those observed for the 51Cr and [3H]TdR radiolabels. Therefore, [111In]Ox can be utilized for relatively short-term (less than 20h) assays with lymphoma targets, as well as for longer-term assays with adherent cells. This should facilitate the testing, with the same radioisotope-release assay, of a wide range of tumor targets for susceptibility to macrophage-mediated cytotoxicity.

Macrophages as a source of tumoricidal activity (tumor-necrotizing factor)

Macrophage-enriched peritoneal exudate cells from mice infected with Mycobacterium bovis BCG, macrophage-like tumor cells (PU 5-1.8), and peritoneal macrophages propagated in vitro with macrophage growth factor released tumoricidal activity into the culture medium within 2 to 3 h after stimulation with nanogram quantities of bacterial lipopolysaccharide. The cytotoxic activities from each of the macrophage culture supernatants eluted from diethylaminoethyl-Sephacel columns at a sodium chloride concentration of 200 mM exhibited a molecular weight of 50,000 to 60,000 as estimated by gel filtration, were stable at 56 degrees C for 30 min, and were active at a pH range of 6 to 10. A rabbit antiserum directed against serum-derived cytotoxic activity (tumor-necrotizing factor) from BCG-infected and lipopolysaccharide-challenged mice inhibited all of the cytotoxic activities generated in vitro. This suggests that the macrophage-derived cytotoxins are identical with serum-derived cytotoxic factor, which further implies that the macrophage is the cellular source of tumor-necrotizing factor.

Cytostatic effects of activated macrophages on tumor target cells: inhibition of cytotoxic action of ARA-C

Studies carried out to explore further the cytotoxic effects of activated macrophages from mice treated with Corynebacterium parvum revealed that their effect on the EMT-6 line of tumor target cells was limited solely to cytostasis with no evidence of a cytocidal effect. In additional studies, the cytostatic effects of activated macrophages markedly reduced the cytotoxic effects of the chemotherapeutic agent cytosine arabinoside on EMT-6 target cells.

In vitro assay of spontaneous cytotoxicity by human monocytes and macrophages against tumor cells

The [3H]proline microcytotoxicity technique has been adopted to examine the spontaneous cytotoxic property of human circulating monocytes (M) derived from the peripheral blood and resident monocytes/macrophages (M0) derived from effusion fluids. A leukocyte fraction is obtained by centrifugation in Ficoll-Hypaque (F-H) gradient. M are then isolated as adherent cells following incubation of the leukocyte fraction in plastic flasks containing 50% fetal calf serum (FCS) in culture medium. M0 are isolated from effusion fluids after first separating the Fc receptor bearing cells (as Fc receptor-7S EA resettes) in F-H gradient and then enriching them as adherent cells. The above techniques yield a M/M0 population of some 90-98% purity. The M/M0 non-selectively lyse tumor cells and allogeneic normal fibroblasts in the 48 h [3H]proline assay. The fibroblasts, however, exhibit considerable resistance to lysis, particularly at lower effector to target ratios. While appreciable levels of cytotoxicity are observed with resident M0 at 6 h, followed by a further increase in the level of cytotoxicity at 24-48 h, circulating M exhibit a consistent level of cytotoxicity only at 24-48 h. When circulating M and resident M0 from the same donor are examined concurrently for cytotoxicity, resident M0 are consistently found to show significantly higher levels of cytotoxicity when compared to circulating M. This may reflect a true functional heterogeneity within this lineage of effector cells or some degree of in vivo activation of resident M0 in malignant and non-malignant effusion fluids. Further studies of spontaneous cytotoxicity by M/M0 through CMC assay techniques, such as the [3H]proline microtoxicity technique, will be useful in the examination of the role of M/M0 in cell mediated immunity and immunosurveillance against cancer.

Macrophage-lymphocyte clusters in the immune response to soluble protein antigen in vitro. VIII. Cinephotomicrographic studies

T cells from immune guinea-pigs produce clusters in vitro with macrophages pulsed with soluble protein antigens. The formation of clusters is antigen-specific. Time-lapse cinephotomicrography was used to study the sequence of events leading to cluster formation and the kinetics of already formed clusters. The central lymphocyte attaches through a broad base to the macrophage during the first few hours of incubation. After several hours, during which the central lymphocyte is situated alone on the surface of the macrophage, free lymphocytes begin to interact for shorter or longer periods of time through their uropods with the central lymphocyte, thus acting as peripheral lymphocytes. In spite of a frequent traffic of peripheral lymphocytes in and out, the cluster is a relatively stable structure. Occasionally the entire complex of lymphocytes leaves the macrophage, moves randomly in the culutre and attaches to a new macrophage or returns to the same macrophage.

A stratified randomized study of intradermal BCG in patients with carcinoma of the bronchus: prolongation of quality but not length of life in inoperable patients

This paper reports the results of a stratified, randomized trial of monthly intradermal injections of Glaxo BCG in addition to conventional therapy (surgery, radiotherapy or no treatment) in a consecutive series of 75 men with confirmed bronchial carcinoma. BCG treatment did not significantly prolong survival but had consistenly more effect in prolonging the period in good general condition and in "acceptable" clinical condition. These were significantly prolonged among the BCG patients (all histopathologies) treated with a full course of radiotherapy (p = 0.01, p = 0.005) and among the 43 patients with squamous carcinoma after adjustment for treatment and general prognostic factors (ratio of observed to expected deaths (O/E) for BCG 0.65, P = 0.025). There was a tendency for BCG patients with oat cell carcinoma to survive less well than controls (O/E for BCG 1.40 not significant). Within comparable groups of patients with squamous carcinoma the delay in decline of general condition was accompanied by reduced weight loss.