Differential effect of recombinant granulocyte macrophage colony-stimulating factor on human monocytes and alveolar macrophages

The effect of granulocyte-macrophage colony-stimulating factor (GM-CSF), a pluripotent cytokine, on tumoricidal activity of alveolar macrophages and monocytes from nonsmoking normal volunteers was compared using [3H]thymidine-labeled human tumor cells (SK-MEL-28, melanoma) as targets. A dose-response study (500-5000 units/ml) of recombinant GM-CSF indicated dramatic differences between cytotoxicity of alveolar macrophages and blood monocytes. Macrophages exhibited significant (P less than 0.01) tumoricidal activity at all GM-CSF doses tested. In contrast, monocytes showed no significant tumoricidal activity at 500 units/ml and significantly (P less than 0.01) less activity than alveolar macrophages at doses of 1000-5000 units/ml. Maximal activity in alveolar macrophages occurred 72-96 h after exposure to 1000-5000 units/ml GM-CSF. Tumoricidal activity may be related to the state of maturation, because monocytes matured in vitro for 7 days displayed enhanced tumoricidal activity after GM-CSF exposure. Tumor necrosis factor alpha and interleukin 1 beta were measured in supernatant fluids of 24-h GM-CSF-treated cells. No significant increase in either cytokine was detected after GM-CSF treatment of alveolar macrophages. Monocyte interleukin 1 beta secretion was not enhanced by GM-CSF; however, tumor necrosis factor alpha secretion was enhanced in some donors (three of five). Superoxide anion production of alveolar macrophages was not enhanced by GM-CSF. These data suggest that alveolar macrophage tumoricidal activity is induced by GM-CSF and is not dependent on oxidative metabolism or secreted forms of interleukin 1 beta or tumor necrosis factor alpha.     

Impaired tumoricidal function of alveolar macrophages from patients with non-small cell lung cancer.

The capacity of alveolar macrophages and peripheral blood monocytes from patients with non-small cell lung cancer to develop tumoricidal function after in vitro stimulation with different macrophage activators was investigated. Alveolar macrophages were found to be impaired in their ability to develop cytotoxic activity compared with either the peripheral blood monocytes from the same patients or alveolar macrophages from patients with nonmalignant lung disorders. This result was observed consistently under diverse culture conditions and with different macrophage activators including gamma-interferon (gamma-IFN), granulocyte-macrophage colony-stimulating factor (GM-CSF), phorbol myristate acetate, or endotoxin. The impairment in tumoricidal function observed in alveolar macrophages was not associated with reduced target cell binding compared to peripheral blood monocytes. Alveolar macrophages from patients with lung cancer were found to secrete significantly greater amounts of tumor necrosis factor (TNF) and interleukin-1 (IL-1) than either peripheral blood monocytes from the same patients or alveolar macrophages from the patients with nonmalignant disorders. These results are consistent with either different regulatory pathways for cytotoxicity and cytokine secretion in the alveolar macrophages of patients with lung cancer or diversity in the subpopulations of cells responsible for these functions.     

Induction of cytokine messenger RNA and secretion in alveolar macrophages and blood monocytes from patients with lung cancer receiving granulocyte-macrophage colony-stimulating factor therapy

Human granulocyte-macrophage colony-stimulating factor (GM-CSF) promotes the proliferation and differentiation of hematopoietic progenitor cells. Although preliminary data are available from clinical trials, the effect of GM-CSF on gene expression of immunocompetent cells in treated patients has not been studied. We previously demonstrated that in vitro treatment with GM-CSF also enhances maturation-related anti-tumor activities in mononuclear phagocytes. The purpose of the present study was to examine the effects of in vivo recombinant GM-CSF therapy on alveolar macrophages and blood monocytes, to determine if these cells demonstrated differential expression of cytokine genes, cytokine production, and tumoricidal activity. Alveolar macrophages and blood monocytes were isolated from 13 patients receiving a range of GM-CSF doses (60-250 micrograms/m2/day) by continuous infusion over a 2-week period. Both monocytes and macrophages were isolated prior to therapy and at day 10 of the infusion. Monocytes, in addition, were isolated on day 3 of infusion. Results indicated that GM-CSF therapy enhanced expression of tumor necrosis factor, interleukin 1, and interleukin 6 mRNA in both monocytes and alveolar macrophages. Differential responses, however, were observed in cytokine secretion; monocytes demonstrated enhanced secretion of all three cytokines by day 3 of treatment, but alveolar macrophages showed only enhanced interleukin 6 secretion at day 10. Monocyte tumoricidal activity after in vitro lipopolysaccharide stimulation was also significantly elevated by day 3 of treatment, but at day 10 activity was not statistically different from pretreatment values in either monocytes or alveolar macrophages. These data indicate that GM-CSF exerts striking time-dependent modulatory effects on gene expression and functional activities of monocytes and alveolar macrophages in vivo, although the responses of the two cell types differ with respect to cytokine secretion.     

Stimulatory effect of vitamin A on tumoricidal activity of rat alveolar macrophages.

F344 rats were given saline, vitamin A placebo or vitamin A analogues orally for 4 consecutive days. The following day they were killed and their alveolar macrophages (AM phi) were harvested by lavage. The functional integrity of the AM phi was determined by their capacity to phagocytize opsonized SRBC and to kill syngeneic adenocarcinoma cell lines nonspecifically. Results showed that 4 days treatment with greater than 100 IU of vitamin A as retinyl palmitate per gram body weight rendered the AM phi tumoricidal against syngeneic mammary adenocarcinoma cell lines (MADB-100 and MADB-200) and that AM phi activated with retinyl palmitate showed increased ability to phagocytize opsonized SRBC. Other retinoids, such as retinoic acid and retinol, had the same effect of inducing tumoricidal activity in rat AM phi. AM phi harvested from normal rats were also rendered tumoricidal by direct interaction with greater than 10(3) IU ml-1 of retinyl palmitate for 24 h in vitro. Thus, vitamin A at high doses can increase the phagocytic and tumoricidal activities of rat AM phi.     

Isolation of tumoricidal macrophages from lung melanoma metastases of mice treated systemically with liposomes containing a lipophilic derivative of muramyl dipeptide

The systemic administration of multilamellar liposomes--composed of phosphatidylcholine and phosphatidylserine (7:3 mol ratio), containing the immunomodulator, muramyl tripeptide phosphatidylethanolamine (MTP-PE)--into C57BL/6N mice bearing the syngeneic B16-BL6 melanoma was associated with the eradication of spontaneous lung and lymph node metastases. Immunofluorescence and electron microscopic analyses revealed that 24 hours after the tumor-bearing mice were given iv injections of liposomes, 15% of the alveolar macrophages and 5% of the metastasis-associated macrophages contained phagocytosed liposomes. However, only macrophages isolated from lungs or metastases of mice given injections of liposomes containing MTP-PE (treatment success), but not macrophages from mice treated with empty liposomes (treatment failure), were tumoricidal against the target cells in vitro. These data provide direct evidence that the regression of established metastases, after treatment of tumor-bearing mice with liposomes containing MTP-PE, was associated with tumoricidal macrophages residing within the metastases.     

In vivo activation of nude mouse macrophages by human melanoma cells

Human melanoma cell lines inoculated ip in outbred nude mice were found to activate locally macrophages, which became tumoricidal for the EL 4 target cells in a 48-hour [3H]thymidine cytotoxicity assay. However, the kinetics of this activation largely depended on the tumorigenicity of the cell line used. One week after inoculation with a poorly tumorigenic cell line (PTCL), peritoneal macrophages showed a maximal tumoricidal activity, which then slowly declined to disappear on the 4th week. Macrophages obtained after inoculation of a highly tumorigenic cell line (HTCL) were also activated, but the level of their tumoricidal activity was somewhat lower and decreased more rapidly. Irradiated melanoma cells were also able to activate peritoneal macrophages. The inoculation of a higher number of melanoma cells (less than or equal to 8 X 10(7) cells) resulted in a parallel increase in the cytotoxicity of peritoneal macrophages when activated by PTCL and in a parallel decrease when activated by HTCL. Activated macrophages taken 1 week after tumor cell inoculation and further kept in vitro without additional stimulation progressively lost their tumoricidal activity, within 48 hours after being harvested from PTCL-inoculated mice and within 24 hours after being collected from HTCL-inoculated animals. These data allied to the in vivo capacity of peritoneal cells rich in activated macrophages to prevent the growth of HTCL in nude mice strongly leaned toward the idea that macrophages are involved in the tumor growth control in the absence of a specific immune response. In addition, tumor-macrophage interactions are likely to vary from tumor to tumor and may contribute to the expression of the xenografting capacity of human tumor cells.     

In vitro effects on tumor cells of macrophages isolated from an early-passage chemically-induced murine sarcoma and from its spontaneous metastases

Macrophages were isolated by adherence from an early-passage chemically-induced tumor in C57BL/6 mice and from its spontaneous lung metastases. Cytolytic activity was measured as release of [³H]-thymidine from prelabelled tumor cells and cytostasis in a post-labelling assay. Normal, unstimulated peritoneal mac-rophages exhibited low but significant non-specific cytotoxic activity at attacker to target (A:T) ratios ≧ 20:1, whereas stimulation of tumor-cell proliferative capacity was consistently observed at A:T ratios ≦ 2:1. Macrophages from the peritoneal cavity of tumor-bearing mice, from the primary tumor or from pooled secondaries had baseline cytotoxic or growth-enhancing (depending on the A:T ratio) potential similar to that of control peritoneal macrophages. In vitro exposure to endotoxin, lymphokine supernatants or partially purified fibroblast interferon augmented the tumoricidal activity of normal and tumor-associated macrophages; tumor-associated macrophages showed no evidence of enhanced responsiveness to these activating stimuli. Tumor cells from the primary neoplasm and its spontaneous metastases were equally susceptible to macrophage tumoricidal activity. It is inferred from in vitro data that the relatively low numbers of non-activated macrophages present within poorly immunogenic metastasizing tumors may have no direct effect or actually stimulate tumor-cell proliferative capacity at the primary tumor site; conversely, disseminating tumor cells might encounter sufficient numbers of mononuclear phagocytes in the circulation and in lungs to permit the expression of macrophage cytotoxicity, at least during the early steps of metastasis formation.     

Tumoricidal effect of macrophages exposed to adriamycin in vivo or in vitro

Peritoneal macrophages from BD IX rats collected 24 hr after an i.p. injection of ADriamycin (10 mg/kg) were cytotoxic to syngeneic cancer cells in culture. In contrast, incubation in vitro in Adriamycin solutions did not evoke tumoricidal activity in peritoneal macrophages, whatever the incubation time (from 1 to 24 hr) and the Adriamycin concentration (from 1 ng to 100 micrograms/ml). Macrophages incubated with Adriamycin in vitro accumulated the drug in their nuclei, whereas macrophages from animals receiving Adriamycin in vivo accumulated it is cytoplasmic vacuoles. Early observation of peritoneal cells after in vivo exposure to Adriamycin shows that Adriamycin is concentrated in mast cell granules which are released and then phagocytosed by peritoneal macrophages. Mast cells exposed to Adriamycin in vitro can induce macrophages to become cytotoxic. These facts explain the difference between macrophages exposed to Adriamycin in vivo and in vitro. Adriamycin fluorescence appears in nuclei of cancer cells incubated with in vivo-labeled macrophages, suggesting that macrophages can directly transfer the drug into cancer cells and therefore play a role in the Adriamycin antitumor effect.     

Procoagulant activity of macrophages associated with different murine neoplasms

Mononuclear phagocytes, an integral part of the lymphoreticular infiltrate of human and experimental tumors, might contribute to tumor-associated fibrin deposition through the development of procoagulant activity (PCA). We have investigated PCA of tumor-associated macrophages (TAM) in 6 transplanted murine tumors in syngeneic hosts; peritoneal macrophages from tumor-bearing and control animals were studied also, as reference cell populations. PCA was evaluated by a one-stage clotting assay immediately after preparation and following incubation in the absence and in the presence of endotoxin. TAM from 5 poorly immunogenic tumors (mFS6, MN/MCA₁, R 80/44, M109 and MS2) had basal PCA levels comparable to or somewhat lower than those of peritoneal macrophages from the same animals. Similar PCA was found in peritoneal macrophages from both control and tumor-bearing animals. Unlike peritoneal macrophages, TAM in all instances failed to respond with increased PCA when exposed to endotoxin in vitro. Failure to respond to endotoxin could not be ascribed to contaminating tumor cells or their products, to the presence of suppressive macrophage populations or to the lack of lymphocyte “help”. TAM from a strongly immunogenic, regressing tumor (MSV sarcoma), in contrast to its non-immunogenic variant, MS2, and to the 4 other tumors mentioned above, expressed high levels of PCA immediately after isolation. The latter did not increase further following in vitro stimulation with endotoxin. When MSV sarcomas were induced in nude mice, TAM showed PCA levels similar to those of the euthymic hosts, suggesting that the procoagulant response was largely independent of T-cell-mediated immunity.     

Possible participation of tumoricidal macrophages in the therapeutic effect of bleomycin on a transplantable rat fibrosarcoma

When bleomycin (BLM) (5 mg/kg/day) was administered i.p. to WKA rats for 5 days from the eighth day after KMT-17 implantation, the therapeutic effects of BLM were demonstrated by complete tumor regression in 50% of the cases and prolongation of the mean survival time of the remainder [survival days, 44.3 +/- 13.6 (SD)]. The combined administration of an antimacrophage agent, carrageenan, with BLM significantly inhibited the therapeutic effects of BLM (cure rate, 33%; survival days, 29.8 +/- 5.8). By means of a Winn assay, the tumor neutralizing activity of both spleen cells and peritoneal cells (PC) against KMT-17 cells was found to be augmented in BLM-treated tumor bearing rats as compared with that in nontreated tumor bearing rats. The enhanced tumor neutralizing activity of spleen cells was not abolished by an anti-rat T-cell serum plus complement treatment and was present in an adherent macrophage enriched population. Similarly, an in vitro [125I]iododeoxyuridine release test enabled us to observe the enhancement of the cytotoxic activity of adherent spleen cells and adherent PC in BLM-treated rats. The cytotoxic activity of the PC of BLM-treated rats was not specific to KMT-17 cells alone but was also observed to operate against antigenically different tumor cells such as WFT-2N, KST-20, and K562 cells. An in vitro carrageenan treatment of PC taken from BLM-treated rats reduced their cytotoxic activity. At the same time, the combined administration of carrageenan and BLM also reduced the cytotoxic activity of PC. These results suggest that the tumoricidal activity of macrophages in tumor bearing rats is augmented after BLM therapy and that the activated tumoricidal macrophages may participate in the host-mediated antitumor effects of BLM.     

MTP-PE: induction of tumoricidal leukocytes in the lungs of rats

Buffer solubilized MTP-PE binds very quickly (within 10 min) to rat alveolar macrophages in vitro and activates them to the tumoricidal state. In vivo, the alveolar macrophages become tumoricidal after intratracheal instillation of MTP-PE. Intranasal application of a relatively large volume (300 microliter) gives the same result, because MTP-PE is then aspirated into the lungs. A wide dose range (1-10,000 micrograms/kg) is effective. Immediately after application of MTP-PE, activated macrophages can be washed out of the lungs. Between 8 and 48 hr after application many tumoricidal neutrophils are also found. Although the tumoricidal activity decreases with time, it can still be demonstrated 8 days after application. Intravenous injection is also effective, but only at 10(3)-fold higher doses. Inhalation of MTP-PE might be of therapeutical value in the treatment of cancer, particularly in the lungs.     

Role of antitumor activity of alveolar macrophages in lung cancer patients

The purpose of this study is to clarify the significance of antitumor activity of alveolar macrophages (AM) in lung cancer patients. AM from tumor-bearing and non-tumor-bearing segments were obtained separately by the lavage of bronchoalveolar tracts of resected lungs of 74 patients with primary lung cancer. Cytostatic activity (CTS) of AM obtained from non-tumor-bearing segments was stable in spite of enlargement of tumor size or progression of N factor. In contrast, CTS of AM obtained from tumor-bearing segments may be augmented at Stage II as compared with Stage I, and suppressed with an advance of stage from II through IV, although the number of Stage II patients was as small as three. Moreover, CTS of AM from tumor-bearing segments was suppressed in N2 as compared with N0 or N1, and also it was suppressed as compared with that of AM from non-tumor-bearing segments in N2 disease. CTS of AM from smokers was suppressed as compared with that of nonsmokers in both tumor-bearing and non-tumor-bearing segments. These results suggest that lung cancer cells or their products may suppress antitumor activity of AM in the tumor-bearing segments at advanced stages, and cigarette smoking is a suppressive factor on antitumor activity of AM.     

Tumoricidal activity and cytokine secretion by tumor-infiltrating macrophages

Murine macrophages from different anatomical sites were compared for their ability to become tumoricidal and to secrete interleukin-1 (IL-1) and tumor necrosis factor (TNF) following stimulation in vitro by several biological response modifiers (BRM). Peritoneal macrophages (PM), alveolar macrophages (AM), and tumor-infiltrating-macrophages (TIM), isolated from B16F10 melanoma colonies in the lung, were incubated overnight with BRM [recombinant murine interferon gamma (rMulFN-gamma), lipopolysaccharide (LPS), muramyl dipeptide (MDP)], either alone or in combination. PM exhibited an increased cytotoxic response following incubation with LPS or rMuIFN-gamma but not with MDP. Both AM and TIM were induced to become tumoricidal following incubation with rMuIFN-gamma plus LPS or rMuIFN-gamma plus MDP but not after stimulation with any BRM alone; the level of cytotoxicity obtained with TIM incubated with rMuIFN-gamma plus LPS was slightly lower than that observed with PM or AM, while with rMuIFN-gamma plus MDP both AM and TIM had lower cytotoxicity than PM. Secretion of IL-I and TNF was observed in PM stimulated with LPS or MDP but not with rMuIFN-gamma. Likewise, secretion of IL-I by AM or TIM was also induced with LPS, although less than that obtained with PM. AM stimulated with LPS secreted larger amounts of TNF than PM while TIM secreted very low amounts of TNF. However, this result may be a consequence of the enzymatic isolation procedure used to obtain TIM since TNF secretion was also impaired in LPS-stimulated normal lung macrophages isolated by a similar enzymatic procedure, or enzyme-treated PM. Our results suggest that TIM obtained from lung metastases share certain functional characteristics with normal AM and respond to BRM in like manner with respect to induction of tumoricidal activity and cytokine secretion.     

Induction of in vitro tumoricidal activity in alveolar macrophages and monocytes from patients with lung cancer

Human alveolar macrophages (AMs) and blood monocytes were obtained from 65 smoking and nonsmoking normal volunteers and 29 patients with lung cancer. The oxidative metabolic response of these cells was measured by superoxide anion production after incubation with lipopolysaccharide. In addition, tumoricidal activity of AMs and monocytes was assessed against [3H]thymidine-labeled tumor target cells. Smoking was associated with depressed AM superoxide anion responses in normals but not in patients. In contrast, smoking appeared to slightly elevate monocyte superoxide anion activity. AMs and monocytes exposed to lipopolysaccharide or recombinant gamma-interferon showed tumoricidal activity in all groups. Mean cytotoxicity values of smoking patients versus smoking normals and exsmoking patients versus nonsmoking normals were not significantly different. Smoking, however, in both patients and normals was associated with significantly (P less than 0.005) depressed AM cytotoxicity levels (less than 40%) compared to nonsmoking volunteers and exsmoking patients. Activated AMs from cancer patients and normals were cytotoxic against three different tumorigenic cell lines but not against a nontumorigenic line. No correlation between monocyte and AM cytotoxic activity within single individuals was found. We conclude that AM and monocytes from smoking and exsmoking patients can be activated after exposure to immunomodulators; however, smoking may be slightly suppressive to cytotoxic responses. These studies provide a rationale for clinical trials of immunomodulators in patients with lung cancer.     

Type-1 transforming growth factor-beta differentially modulates tumoricidal activity of murine peritoneal macrophages against metastatic variants of the B16 murine melanoma

Transforming growth factor-beta 1 (TGF-beta 1) renders mouse peritoneal macrophages tumoricidal against metastatic variants of the B16 mouse melanoma in vitro. Both direct cytotoxicity and indirect cytotoxicity were observed. A subthreshold concentration (10 U/ml) of recombinant murine interferon-gamma (rMuIFN-gamma) enhanced the direct tumoricidal activity of TGF-beta 1-activated macrophages from 29% to 88% but did not change their indirect tumoricidal profile. Data obtained from macrophages preincubated with either TGF-beta 1 or rMuIFN-gamma showed that TGF-b1 can initiate tumoricidal activity better than rMuIFN-gamma. These effects were plasma-membrane mediated because targeting macrophages with liposomal TGF-beta 1 was ineffective. The order of tumoricidal susceptibility of the B16 melanoma lines to activated macrophages was B16F1 > B16F10 > B16BL6, in inverse order of metastatic potential.     

Synergistic activation of rat alveolar macrophages by cepharanthine and OK-432

We studied the synergistic activation of rat alveolar macrophages (AM) by cepharanthine (Ceph.) and OK-432. Rat AM could be rendered much more tumoricidal against Walker-256 tumors in vitro after the i.v. injection of ceph. (5 mg/Kg) and OK-432 (5 KE/rat) thao of ceph. or OK-432 only. Radioactivity of 14C-acetate-OK-432 trapped in murine lung after the i.v. injection of mixed of ceph. was much higher than of 14C-acetate-OK-432 only. Rat AM could be rendered tumoricidal by incubation in vitro with OK-432, but not with ceph. This finding suggests that if OK-432 is injected intravenously with mixed of with ceph., of OK-432 is trapped much more up by the lung without mixture, therefore AM can be much more tumoricidal. Intravenous administration of OK-432 with ceph. may be useful for reduction of lung metastasis by tumoricidal AM.     

Amino acid profiles in tumor-bearing and pair-fed nontumor-bearing malnourished rats

To investigate the metabolic and organ changes accompanying growth of a malignant tumor, ten male Fisher 344 rats weighing 150 to 200 g were inoculated subcutaneously with 10(6) viable MCA sarcoma cells (tumor-bearing). Ten other rats (controls) were similarly inoculated with saline. Both groups were allowed food and water ad libitum. An additional ten rats (pair-fed) were inoculated with saline and fed the same mean daily food intake as the tumor-bearing rats. Thirty-five days after inoculation the rats were killed by exsanguination. Livers, spleens, and tumors were weighed, and amino acid profiles and biochemical parameters were measured. Liver and spleen weights in tumor-bearing rats were significantly greater than control rats (P less than 0.05 and P less than 0.01, respectively). Liver weight in pair-fed rats was significantly less than control rats (P less than 0.01), but spleen weight was greater (P less than 0.01). Amino acid profiles of tumor-bearing rats and pair-fed rats were different from each other and from those of control rats. Branched-chain amino acids were lowest in tumor-bearing rats and significantly different from control and pair-fed rats. Lysine was significantly higher (P less than 0.01) and arginine significantly lower (P less than 0.05) in tumor-bearing rats compared with control rats. These different plasma amino acid profiles and changes in serum biochemistry of cachectic tumor-bearing rats compared with malnourished pair-fed rats suggest specific tumor effects on host metabolism not mediated solely by anorexia.     

Interactions with host macrophages and ability of human melanoma cell lines to grow in nude mice

The interactions of nude mouse macrophages with five human melanoma cell lines, characterized by their resistance to mouse NK activity and varying in their ability to grow s.c. in nude mice, were investigated. These lines were equally susceptible in vitro to both cytostatic and tumoricidal activities of activated peritoneal macrophages collected from nude mice inoculated 3 days previously with Brucella abortus B19R strains. I.p. injection of a poorly tumorigenic melanoma cell line (PTCL) in nude mice was followed by the local appearance of macrophages able to kill these cells in a 48-hr 3H-thymidine cytotoxicity assay. The level of tumoricidal macrophages was maximum for the first week and then slowly declined to disappear by the 4th week following PTCL inoculation. The use of an HTCL instead of a PTCL also induced macrophages able to kill HTCL cells, but the cytotoxicity level was lower and the activity disappeared more rapidly. In cross-experiments using PTCL-activated macrophages as effectors on HTCL targets, these cells were found to be less sensitive than PTCL cells when macrophages were taken at weeks 2 and 3 following PTCL inoculation. To investigate whether tumoricidal macrophages activated in vivo with human melanoma cells could also act in vivo, we inoculated these s.c. into nude mice, simultaneously with live HTCL cells. Peritoneal cells rich in melanoma-activated macrophages prevented HTCL growth in most recipients, whereas spleen cells from the same donor mice did not modify the tumor take. These data indicate that xenogeneic tumors could activate nude mouse macrophages in vivo and suggest that the ability of human tumors to grow in nude mice could be related to their capacity to activate host macrophages locally and to the susceptibility of human tumor cells to the tumoricidal activity of activated macrophages.     

Role of tumor necrosis factor and interleukin 1 in gamma-interferon-promoted activation of mouse tumoricidal macrophages

The purpose of this study was to determine if recombinant murine interleukin 1 beta (rMu-IL-1 beta) alone or in combination with recombinant murine gamma-interferon (rMu-IFN-gamma) could activate murine macrophages to be tumoricidal against tumor necrosis factor (TNF)-insensitive target cells and to evaluate the possible role of interleukin 1 (IL-1) in murine macrophage activation by recombinant murine tumor necrosis factor (rMu-TNF) plus rMu-IFN-gamma. rMu-IL-1 beta and rMu-TNF alone or in combination could neither directly lyse the TNF-insensitive P815 mastocytoma nor activate resident peritoneal macrophages to be tumoricidal for this target. A synergistic induction of tumoricidal macrophage activity against P815 occurred, however, when either of these monokines was combined with rMu-IFN-gamma. The tumoricidal activity obtained was transitory, and the level of activity was dependent upon the monokine concentration and the length of induction period. Murine macrophages stimulated under the same conditions used to induce tumoricidal activity with rMu-TNF plus rMu-IFN-gamma or with rMu-IL-1 plus rMu-IFN-gamma were shown to produce low concentrations of IL-1 or TNF, respectively. Thus, a bidirectional cross-induction of the production of the two monokines occurred. The monokine production was also quite transitory, and the time of peak production of the monokines (12 h) was found to precede the time of peak tumoricidal activation (24 h). Using neutralizing antisera specific for rMu-IL-1s and rMu-TNF, the cross-induced production of TNF was shown to be required for macrophage tumoricidal activation by rMu-IL-1 beta alone (TNF-sensitive targets) or in combination with rMu-IFN-gamma (TNF-insensitive targets). There was no evidence, however, that the production of IL-1 was required for macrophage activation by rMu-TNF in combination with rMu-IFN-gamma.     

瘤内／瘤周注射巨噬细胞集落刺激因子或（和）干扰素—γ基因转染的 …

目的 观察巨噬细胞集落刺激因子（Ｍ－ＣＳＦ）和干扰素－γ（ＩＦＮ－γ）基因单独或联合转染的巨噬细胞对局部黑色素瘤的治疗效果及相关免疫机理。