Rat alveolar macrophage production of chemoattractants for neutrophils: response to Escherichia coli endotoxin.

Endotoxemia in rats is associated with the accumulation of neutrophils (polymorphonuclear leukocytes) within the airspaces of the lung. Polymorphonuclear leukocyte influx appears to be regulated by the intrapulmonary accumulation of chemotactic activity. Since alveolar macrophages (AMS) are prevalent cells in the airspace and are known to release a variety of chemotactic factors, we investigated the effect of endotoxin exposure on AM production of chemotactic activity. We tested the hypothesis that endotoxin-exposed AMs have an augmented ability to produce chemoattractants. We recovered AMs by bronchoalveolar lavage from control rats and from rats treated in vivo with a "low dose" (2.5 mg/kg) or a "high dose" (5.0 mg/kg) of Escherichia coli endotoxin. These AMs were then cultured in vitro for 15 h in the absence or the presence of endotoxin (15 and 30 micrograms/ml) to stimulate the cells to produce chemoattractants. We found that in vitro endotoxin stimulated normal AMs to secrete chemoattractants in a dose-dependent fashion. AMs from rats treated with endotoxin in vivo spontaneously secreted more chemoattractants than AMs from control rats. Exposure to in vivo endotoxin followed by in vitro stimulation with endotoxin resulted in an even greater production of chemoattractants by AMs. We found a significant association between the percent polymorphonuclear leukocytes recovered by bronchoalveolar lavage from the airspaces and the production of chemoattractants by AMs from the same specimen. The level of chemotactic activity spontaneously produced by AMs predicted the degree of stimulated production of chemotactic activity. Partial purification indicated that this chemotactic activity has two molecular weight peaks, one near 1,000 and the other near 50,000. The activity was stable at 100 degrees C for at least 30 min and was degradable by trypsinization. We conclude that endotoxin can induce AM production of chemoattractants and that prior exposure to endotoxin in vivo affects the response of AM to in vitro endotoxin exposure. By inference, it is possible that this endotoxin-macrophage interaction may serve as a biologic amplifier of the effects of endotoxin and may have a role in the pathogenesis of septic lung injury in humans.     

Continuous secretion of monocyte chemotactic factors and fibroblast growth factors by alveolar macrophages following a single exposure to bleomycin in vitro.

It has been shown in previous studies that alveolar macrophages incubated with bleomycin in vitro for 2 to 18 hours secrete monocyte chemotactic factors and fibroblast growth factors (MDGF). The purpose of the current experiments was to determine if alveolar macrophages similarly stimulated with bleomycin would continue to secrete these factors once the stimulus was removed. Alveolar macrophages from normal rats were exposed to bleomycin for 18 hours after which bleomycin was removed and macrophages maintained in culture for 35 days. Conditioned medium (CM) was collected and assayed at weekly intervals. In comparison with nonstimulated controls, bleomycin-stimulated macrophages secreted greater amounts of both monocyte chemotactic factors and MDGF for 35 days after exposure to bleomycin; with a significant difference noted between bleomycin and control macrophages for the first 21 days (P less than 0.02). In agreement with past work, the chemotactic activity in bleomycin-CM was due to fibronectin, as evidenced by the almost complete inhibition of activity by anti-fibronectin antibodies. The time course of secretion of chemotactic and growth factors after a single exposure to bleomycin in vitro was similar to that induced by in vivo exposure of macrophages to this drug. The data suggest that a similar direct activation of macrophages by bleomycin may promote the long-term production of these factors in vivo, resulting in continued monocyte recruitment and promotion of fibroblast proliferation in fibrotic lungs.     

Changes in distribution, morphology, and tumor necrosis factor-alpha secretion of alveolar macrophage subpopulations during the development of bleomycin-induced pulmonary fibrosis.

Previous studies indicate that heterogeneous alveolar macrophages (AM) play a pivotal role in events associated with bleomycin-induced pulmonary fibrosis. A critical role has been suggested for tumor necrosis factor-alpha (TNF-alpha), a product of activated macrophages, in this fibrotic process. The present study examined whether the characteristics and function (TNF-alpha secretion) of rat AM subpopulations were altered during the development of bleomycin-induced fibrosis. After intratracheal bleomycin treatment, AM were separated into 18 density-defined subpopulations. Bleomycin treatment altered the distribution and morphology of AM subpopulations of densities 1.017 to 1.061 g/ml at all time points studied (4, 14, and 28 days). Subpopulations of densities 1.090 to 1.141 g/ml were affected only at 4 days after bleomycin treatment. Tumor necrosis factor-alpha secretion increased with time in 14- and 28-day samples of bleomycin-treated rats, particularly in subpopulations of densities 1.075 to 1.097 g/ml. These data indicate that alterations in the distribution, morphology, and function of AM subpopulations accompany the development of bleomycin-induced pulmonary fibrosis. When coupled with previous studies suggesting that TNF-alpha plays a role in the fibrotic process in this disease model, these data indicate that AM of densities 1.075 to 1.097 g/ml are responsible for the production of TNF-alpha associated with bleomycin-induced pulmonary fibrosis.     

Effect of Pseudomonas aeruginosa rhamnolipid on human neutrophil and monocyte function

The effect of rhamnolipid purified from culture supernatant of Pseudomonas aeruginosa on human peripheral blood neutrophil and monocyte function was studied. It was shown that rhamnolipid at concentrations of up to 100 micrograms/ml did not affect neutrophil and monocyte chemotaxis towards various chemoattractants. The rhamnolipid by itself did not show chemotactic activity and did not induce any oxidative burst response. Preincubation of monocytes with rhamnolipid enhanced the oxidative burst response of these cells to phorbol myristate acetate (PMA) and to opsonized zymosan by 2 to 5 fold. The priming effect was observed both in a superoxide assay and in a chemiluminescence assay. However, rhamnolipid did not prime the neutrophil oxidative burst response. Monocytes/macrophages are involved in the inflammatory process in the lung infections caused by P. aeruginosa and oxygen radicals are known to cause tissue damage. Therefore the priming by rhamnolipid of monocytes for enhanced generation of oxygen radicals may play a role in the pathogenesis of tissue damage in the lungs of cystic fibrosis patients with P. aeruginosa infections.     

Monocyte chemoattractant protein-1 and RANTES are chemotactic for graft infiltrating lymphocytes during acute lung allograft rejection

Graft infiltrating lymphocytes (GILs) are crucial to rejection of lung allografts. However, chemotactic activities, chemokines responsible for GIL recruitment, and cells involved in chemokine production during lung allograft rejection have not been evaluated. This study determined whether chemotactic activity for GILs is upregulated, and whether the chemokines monocyte chemoattractant protein (MCP)-1 and regulated on activation, normal T cells expressed and secreted (RANTES) have roles in GIL chemotaxis during lung allograft rejection. F344 (RT1(lv1)) rat lung allografts were transplanted into WKY (RT1(l)) recipients. Chemotactic activity for GILs and quantities of MCP-1 and RANTES were determined in allograft bronchoalveolar lavage fluid 1 wk after transplantation. Data showed that during rejection, chemotactic activity for GILs is upregulated, MCP-1 and RANTES are produced locally, and both MCP-1 and RANTES are operative in GIL recruitment. Immunohistochemistry showed that alveolar macrophages (AMs) were the major source of MCP-1 and that other lung cells, including AMs, were the source of RANTES. Further, depletion of AMs in the donor lung before transplantation downregulated chemotaxis for GILs and production of MCP-1 during rejection episodes. These data show that chemotaxis for GILs is upregulated locally during lung allograft rejection, and that MCP-1 and RANTES contribute to GIL recruitment during the rejection response.     

小鼠肺纤维化模型中基质金属蛋白酶-9及其抑制剂表达水平的变化

目的 :研究小鼠博来霉素在肺纤维化模型中肺泡巨噬细胞(AM)分泌的基质金属蛋白酶 9(MMP 9)和基质金属蛋白酶抑制剂 1(TIMP 1)的表达随着时间的变化 ,观察肺纤维化中MMP 9和TIMP 1的表达是否存在失衡。方法 :以博来霉素诱导建立小鼠肺纤维化模型 ,采用HE染色观察肺部胶原沉积状况。选用抗CD6 8mAb ,采用微小免疫磁珠法分离纯化肺泡灌洗液中的AM ,用Hoechst 332 5 8染色AM ,在下光镜高倍视野计数法评估AM的纯度和活性 ,用EIA法检测AM上清液中MMP 9和TIMP 1的表达。结果 :肺组织切片HE染色显示小鼠肺部胶原沉积在 1、3、7、14、2 8d呈逐渐加重趋势。粗分离的AM纯度为 (82 .5± 2 .5 ) %。采用微小免疫磁珠法分离肺泡灌洗液中的AM纯度可达到 (99.3± 0 .7) % (P <0 .0 5 )。纯化后的细胞存活率为 (92 .5± 1.8) % ,与纯化前的 (92 .7± 2 .0 ) % ,相差不大 (P >0 .0 5 )。随着小鼠肺间质纤维化的进展 ,MMP 9的分泌量逐渐减少 ,而TIMP 1的表达量逐渐增加。结论 :在小鼠肺纤维化中AM分泌的MMP 9和TIMP 1之间存在失衡 ,表明基质降解系统受到抑制     

Aggravation of bleomycin-induced pulmonary inflammation and fibrosis in mice lacking peroxiredoxin I

Oxidative stress plays an important role in the pathogenesis of acute lung injury and pulmonary fibrosis. Peroxiredoxin (Prx) I is a cellular antioxidant enzyme induced under stress conditions. In the present study, the protective effects of Prx I on the development of bleomycin-induced acute pulmonary inflammation and pulmonary fibrosis were investigated using Prx I-deficient mice. Survival of Prx I-deficient mice after bleomycin administration was significantly lower than that of wild-type mice, corresponding with enhanced acute pulmonary inflammation and fibrosis. The level of inflammatory cytokines and chemokines, such as TNF-α, macrophage inflammatory protein-2, and monocyte chemotactic protein-1, was significantly elevated in the bronchoalveolar lavage fluid of Prx I-deficient mice after bleomycin administration. Furthermore, the level of 8-isoprostane, an oxidative stress marker, and the concentration and alveolar macrophage expression of macrophage migration inhibitory factor were elevated in the lungs of Prx I-deficient mice after bleomycin administration. The exacerbation of bleomycin-induced pulmonary inflammation and fibrosis in Prx I-deficient mice was inhibited by treatment with N-acetyl-L-cysteine, a radical scavenger, or with (S,R)-3-(4-hydroxyphenyl)-4,5-dihydro-5-isoxazole acetic acid methyl ester, a tautomerase inhibitor of macrophage migration inhibitory factor. These findings suggest that mice lacking Prx I are highly susceptible to bleomycin-induced pulmonary inflammation and fibrosis because of increases in pulmonary oxidant levels and macrophage migration inhibitory factor activity in response to bleomycin.     

Effect of acute inflammatory lung injury on the expression of monocyte chemoattractant protein-1 (MCP-1) in rat pulmonary alveolar macrophages.

Using a well-characterized rat model of immune complex-mediated acute inflammatory lung injury, we determined that there is a time-dependent elaboration of monocyte chemotactic activity in bronchoalveolar lavage fluid. Monocyte chemotactic activity is also significantly enhanced in culture supernatants from pulmonary alveolar macrophages (PAMs) from injured rat lungs. Northern hybridization analysis revealed markedly increased expression of rat monocyte chemoattractant protein 1 (MCP-1) mRNA in PAMs obtained from rats with immune complex-induced lung injury. The increased expression of MCP-1 mRNA and associated increase in monocyte chemotactic activity present in culture supernatants of PAMs from injured rat lungs suggest that PAMs may participate in the pathogenesis of acute inflammatory lung injury by the secretion of monocyte chemoattractants including MCP-1.     

The effects of bleomycin on alveolar macrophage growth factor secretion.

Previous work in this laboratory has demonstrated increased secretion of fibroblast growth factor (MDGF) activity by alveolar macrophages obtained from mice with bleomycin-induced pulmonary fibrosis. The mechanism by which bleomycin promotes this increase in MDGF secretion is not clear, however. The purpose of this study was to determine the direct effects of bleomycin on alveolar macrophages. Normal rat alveolar macrophages obtained by lavage were cultured in the presence or absence of bleomycin; conditioned media from these cultures were dialyzed to remove bleomycin and then assayed in vitro for MDGF activity. Alveolar macrophages incubated with 0.01 microgram to 1 microgram/ml bleomycin for 18 hours secreted significantly more MDGF than macrophages incubated without bleomycin. Viability of macrophages as determined by exclusion of trypan blue and release of LDH was unaffected by any dose tested. Maximal MDGF production was seen with bleomycin doses of greater than or equal to 0.1 microgram/ml. When alveolar macrophages were incubated with 0.1 microgram/ml bleomycin for 0.5-18 hours, MDGF activity was detected as early as 1 hour, with peak responses found at 4-8 hours. Macrophages stimulated with bleomycin continued to produce significant amounts of MDGF even after bleomycin was removed and replaced with fresh (bleomycin-free) media. MDGF secretion by bleomycin-stimulated alveolar macrophages was inhibited by cycloheximide, and the 5-lipoxygenase inhibitors NDGA (nordihydroguairetic acid) and BW755c, indicating not only a requirement for protein synthesis but also for metabolites of the 5-lipoxygenase pathway of arachidonic acid metabolism for full expression of activity(ABSTRACT TRUNCATED AT 250 WORDS)     

Inhibition of pulmonary fibrosis by the chemokine IP-10/CXCL10

Pulmonary fibrosis is an enigmatic and devastating disease with few treatment options, now thought to result from abnormal wound healing in the lung in response to injury. We have previously noted a role for the chemokine interferon gamma-inducible protein of 10 kD (IP-10)/CXC chemokine ligand 10 in the regulation of cutaneous wound healing, and consequently investigated whether IP-10 regulates pulmonary fibrosis. We found that IP-10 is highly expressed in a mouse model of pulmonary fibrosis induced by bleomycin. IP-10-deficient mice exhibited increased pulmonary fibrosis after administration of bleomycin, suggesting that IP-10 limits the development of fibrosis in this model. Substantial fibroblast chemoattractant and proliferative activities were generated in the lung after bleomycin exposure. IP-10 significantly inhibited fibroblast responses to the chemotactic, but not the proliferative activity generated, suggesting that IP-10 may attenuate fibroblast accumulation in bleomycin-induced pulmonary fibrosis by limiting fibroblast migration. Consistent with this inhibitory activity of IP-10 on fibroblast migration, fibroblast accumulation in the lung after bleomycin exposure was dramatically increased in IP-10-deficient mice compared with wild-type mice. Conversely, transgenic mice overexpressing IP-10 were protected from mortality after bleomycin exposure, and demonstrated decreased fibroblast accumulation in the lung after challenge compared with wild-type mice. Our findings suggest that interruption of fibroblast recruitment may represent a novel therapeutic strategy for pulmonary fibrosis, which could have applicability to a wide range of fibrotic illnesses.     

Class II antigens of the major histocompatibility complex are increased in lungs of bleomycin-treated rats.

The expression of class II molecules (Ia) of the major histocompatibility complex by isolated alveolar macrophages (AM) and alveolar type II cells from the lungs of rats with bleomycin-induced pulmonary fibrosis was examined. The percentage of Ia-positive AM and type II cells from rats treated with bleomycin as detected by flow cytometry was increased three times and two times, respectively, over the values obtained from control rats. The relative density of Ia expression, determined with a radioimmunoassay technique, showed a 50% increase in Ia density on AM and a 35% increase on type II cells. Recombinant interferon-gamma increased the expression of Ia on type II cells in vitro by 35% to the level obtained on type II cells in bleomycin-induced lung disease. We conclude that the increase of Ia expression on cells of the immune system and on pulmonary epithelial cells may have an important role in the initiation and/or amplification of inflammatory reactions in the lung and may contribute to the development of pulmonary fibrosis.     

Induction of selective biological responses to chemoattractants in a human monocyte-like cell line

The availability of monocyte cell lines that can be induced to differentiate in a predictable fashion can provide important tools for the study of the biochemical mechanisms of specific cellular responses. The U937 human monocyte cell line was previously shown to differentiate into chemotactically responsive cells when incubated with supernatants of lectin-stimulated lymphocytes (conditioned medium). Considering the heterogeneous nature of stimulated lymphocyte supernatants, attempts were made to identify well-defined agents that could reproducibly induce U937 cell differentiation. Both dimethyl sulfoxide and dibutyryl cAMP induced expression of receptors for the N-formylated oligopeptide chemoattractants in U937 cells. Unstimulated U937 cells contained no detectable receptors. After cells were exposed to 1 mM dibutyryl cAMP, 1.3% dimethyl sulfoxide, or 5% conditioned medium for 72 h, the average number of oligopeptide chemoattractant receptors per U937 cell was 33,000, 4,000, and 3,400, respectively. Specific binding proteins for the chemoattractants were identified by covalent affinity labeling on the differentiated U937 cells as well as on normal human monocytes. Cells exposed to conditioned medium responded chemotactically, secreted lysosomal enzymes, and formed superoxide anion when incubated with the chemoattractant. Treatment of U937 cells with dibutyryl cAMP resulted in the most reproducible and rapid increase in the number of chemoattractant receptors as well as in chemotactic responsiveness. The receptors on dibutyryl cAMP-treated cells and on dimethyl sulfoxide-treated cells initiated chemotaxis and lysosomal enzyme secretion in response to chemoattractants, but not the formation of superoxide anion. These findings demonstrate that development of the chemotactic and respiratory burst functions during the differentiation of a monocyte-like cell line can occur independently.     

Inhibition of bleomycin-induced pulmonary fibrosis by lipopolysaccharide

Current evidence suggests that bleomycin toxicity may be attributable to its DNA degradative activity possibly via generation of free radicals and O2 metabolites as mediators. Since lipopolysaccharide (LPS) has been known to provide protection against O2 toxicity, which is correlated with increased activity of O2 metabolite-detoxifying enzymes, the effect of this agent on bleomycin-induced pulmonary fibrosis was examined. Endotracheal bleomycin administration caused increased lung collagen synthesis. A single intraperitoneal injection of LPS (500 micrograms/kg) at day zero significantly decreased these increases. Total bleomycin-induced lung collagen increase was also significantly reduced. LPS alone had no significant effect on total lung catalase activity. Glutathiione peroxidase activity, however, was significantly decreased by 15.8% compared to untreated animals at 2 days after LPS treatment and remained unchanged at other time points. In addition, superoxide dismutase activity was significantly elevated by 30% above untreated animals only at 14 days after LPS administration and remained unchanged at other time points. Endotracheal bleomycin administration alone caused significant reductions in catalase activity at 2 days and 2 weeks after treatment, whereas glutathione peroxidase activity increased above control untreated animals at 2 and 4 weeks, respectively. Superoxide dismutase activity was unaffected by bleomycin treatment. Pretreatment with LPS before bleomycin prevented these reductions or caused increases in the activities of these enzymes at 2 days. Glutathione peroxidase was increased and was significantly greater than those animals treated with bleomycin alone. Catalase also was higher in the LPS plus bleomycin group (by 22.2%, p less than 0.05) than the bleomycin group alone. Compared to the effects on lung collagen synthesis and content, LPS treatment resulted in much less dramatic changes in total lung antioxidant enzyme activities. This discrepancy between the intensity of LPS effects on lung O2 metabolite-detoxifying enzymes and that on pulmonary fibrosis implies that the LPS-ameliorating effect on pulmonary fibrosis could not be totally explained by increased ability to detoxify O2 metabolites. Rather, the data would favor the possibility that LPS inhibits bleomycin-induced pulmonary fibrosis either by its known immunosuppressive effects or some other unknown mechanism. The former would be in agreement with previous data which suggest that an intact immune response is necessary for complete expression of the fibrogenic response to bleomycin.     

The role of soluble factors in bleomycin-induced pulmonary fibrosis.

Endotracheal administration of bleomycin causes pulmonary fibrosis characterized by increased collagen synthesis and deposition. Incubation of normal lung mince with neutral salt soluble extracts of lungs from normal and bleomycin-treated rats caused a dose-dependent inhibition of collagen and noncollagenous protein synthesis. Bleomycin-treated lung extracts, however, were significantly less effective in such inhibition when compared with normal lung extracts. This inhibitory activity was not diminished by dialysis in tubing with nominal molecular weight cutoff of 10,000 but was destroyed by heat (70 C) and trypsin digestion. This inhibitory activity could not be ascribed to residual serum or bleomycin in the lung extracts. Fractionation on Sephacryl S-200 (Pharmacia, Piscataway, NJ) showed inhibitory activity to be heterogeneous with Mr (apparent molecular weight) greater than 100,000. Extracts from spleen showed similar inhibitory activity but showed no difference in intensity between normal and bleomycin-treated spleen. These data suggest that loss or decrease in production of lung inhibitory regulatory factors is partly responsible for the noted increase in collagen production and deposition in bleomycin-induced pulmonary fibrosis.     

吉非替尼通过增加Foxo3a活性抑制肺纤维化小鼠上皮-间质转分化

 目的：研究吉非替尼对肺纤维化小鼠转录因子叉头框蛋白O3a(Foxo3a)活性、α-平滑肌肌动蛋白（α-SMA）水平及相关通路的影响,探讨吉非替尼抑制肺上皮-间质转分化的可能机制。方法：将30只SPF级雌性昆明小鼠随机分为3组：对照组（生理盐水气管内雾化）、博来霉素组（博来霉素3 mg/kg溶于100 μL生理盐水气管内雾化）和吉非替尼处理组（博来霉素气管内雾化后,每天吉非替尼20 mg/kg溶于100 μL生理盐水灌胃）。实验第14天收集样本,将小鼠肺组织置于10%中性甲醛固定,石蜡包埋切片后行HE与Masson染色;RT-PCR法检测Foxo3a和α-SMA mRNA表达水平;Western blotting法检测表皮生长因子受体（EGFR）、Akt、Foxo3a和α-SMA蛋白表达水平。结果：吉非替尼处理组小鼠肺组织病理损伤较博来霉素组明显减轻,胶原沉积明显减少,炎症损伤评分及纤维化评分明显下降（均P<0.01）,Foxo3a mRNA表达水平明显升高（P<0.05）,α-SMA mRNA表达水平明显下降（P<0.05）,总Foxo3a蛋白表达增加,但Foxo3a磷酸化水平显著下降(P<0.01),胞核Foxo3a蛋白明显增加（P<0.05）;同时,EGFR和Akt磷酸化水平也显著下降（P<0.01,P<0.05）,上皮-间质转分化标志蛋白α-SMA表达水平明显降低（P<0.05）。结论:吉非替尼抑制博来霉素诱导的肺纤维化,其机制可能与抑制EGFR/Akt通路活化、增强转录因子Foxo3a活性、从而抑制上皮-间质转分化密切相关。     

A neutrophil-derived proteolytic inactive elastase homologue (hHBP) mediates reversible contraction of fibroblasts and endothelial cell monolayers and stimulates monocyte survival and thrombospondin secretion.

Human heparin-binding protein (hHBP) is a recently discovered proteolytically inactive neutrophil elastase homologue with sequence identity to azurocidin and CAP37. The protein has antibacterial properties and chemotactic activity toward monocytes. In the present work, we show that monocytes, cultured under serum-free conditions, developed morphological changes and formed multicellular aggregates 4 h after the addition of hHBP at a concentration of 10 micrograms/ml. However, after prolonged incubation (11 days) with unchanged medium, the cells spread again. The hHBP-treated cells had a two- to threefold increase in survival compared to control cells, measured using trypan blue as an indicator of living cells. Differentiation of the alive cells to macrophages was detected by changes in morphology, a threefold increase in protein content, and a three- to fourfold increase in acid phosphatase activity. When monocytes in parallel experiments were labelled with [35S]methionine de novo synthesis and secretion of thrombospondin in a dose-dependent manner was observed after 16 h, with half-maximal secretion at 2 micrograms hHBP/ml and a maximal 12-fold increase in secretion with respect to controls at 16 micrograms/ml. Supplementary labeling with [35S]sulfate revealed that the same monocytes down-regulated the secretion of a large proteoglycan (300-400 kd), apparently also with a half-maximal decrease rate at 2 micrograms/ml hHBP. Exposure of confluent fibroblast and endothelial cell monolayers to hHBP (10 micrograms/ml) in the absence of fetal calf serum resulted in cell contraction leaving gaps between cells, the phenomenon being recognizable within 4 h after addition of hHBP. Addition of fetal calf serum to a concentration of 10% completely restored the monolayers. A unique role of hHBP in host defense involving recruitment of monocytes and a key function of hHBP in neutrophil extravasation in response to inflammatory chemotactic signals such as leukotriene B4, complement peptide C5a, and N-formyl-methionyl-leucyl-phenylalanine are suggested.     

The development of bleomycin-induced pulmonary fibrosis in neutrophil-depleted and complement-depleted rats.

The development of bleomycin-induced pulmonary fibrosis was studied in rats depleted of neutrophils for 1 week and in rats depleted of complement for 1 week. Lung injury was assessed by histologic evaluation and by the biochemical measurement of total lung collagen. Qualitatively, histologic evidence of damage induced by bleomycin showed that damage progressed in a similar manner in neutropenic and complement-depleted animals when compared with normal animals. However, analysis of total lung collagen at 1 week after bleomycin administration revealed that collagen deposition was increased in neutropenic animals and decreased in animals depleted of complement when compared with untreated animals that received bleomycin. There were no significant differences in lung collagen levels at 1 month after bleomycin treatment in neutrophil-depleted or complement-depleted animals when compared with animals that received bleomycin alone.     

Monocyte chemotaxis mediated by formyl-methionyl-leucyl-phenylalanine conjugated with monoclonal antibodies against human ovarian carcinoma

Availability of a chemically defined chemoattractant (fMLP) and of appropriate monoclonal antibodies may permit local manipulation of the inflammatory response to human tumors. fMLP has been conjugated with two monoclonal antibodies (OC125 and OC133) which react with human ovarian carcinomas. Conjugates retained the ability to bind to a human ovarian carcinoma line (OVCA433) judged by indirect immunofluorescence and by radioimmunoassay. The fMLP conjugate was maximally chemotactic for human blood monocytes and human peritoneal macrophages at protein concentrations of 300-900 micrograms/ml. Conjugates stimulated chemotaxis rather than chemokinesis. After incubation with an fMLP-antibody conjugate, antigen positive OVCA433 cells released chemotactic activity and attracted monocytes in vitro, whereas an antigen-negative ovarian cell line failed to do so. As monocytes can be important effectors of antibody dependent cell mediated cytoxicity, fMLP conjugates might increase monocyte concentrations at tumor sites and potentiate serotherapy for certain human neoplasms.