Cells In Lungs Of Mice Research Articles

Lipopolysaccharide Induces Mucus Cell Metaplasia in Mouse Lung

A murine model of lipopolysaccharide (LPS)-induced airway inflammation and epithelial cell phenotypic change, and the time courses of these events are described. A single intratracheal instillation of Pseudomonas aeruginosa LPS in mice resulted in massive recruitment of neutrophils to the lung 2 d after treatment as assessed by differential cell counts of the inflammatory cells in bronchoalveolar lavage fluid and histologic assessment of hematoxylin and eosin (H&E)-stained lung sections. The LPS-induced neutrophilic inflammation subsided substantially on Day 4 and essentially vanished by Day 7. Airway epithelial mucus cells were not detected by Alcian blue periodic acid-Schiff staining until Day 4 after LPS treatment and became more abundant in number as well as in mucus content on Day 7. The expression of Muc5ac messenger RNA (mRNA) as well as glycoprotein was enhanced on Day 2, peaked on Day 4, and decreased on Day 7, whereas enhanced expression of mucin core 2 beta6 N-acetylglucosaminyltransferase (C2GnT)-M mRNA was not detected until Day 4 and peaked on Day 7. The expression of C2GnT-L mRNA in the lung, a marker for activated leukocytes as well as mucus cells, peaked on Day 2 and remained moderately high until Day 7. C2GnT-L mRNA expression in LPS-treated lung correlated with the presence of neutrophils and the appearance of mucus cells in the airway epithelium. We conclude that mucus cell metaplasia and hyperplasia can be generated in mouse lungs with a single intratracheal instillation of LPS. In addition, C2GnT-M may serve as a marker for mucus cells in mouse lung. This LPS-induced mucus cell metaplasia and hyperplasia model should be useful for the study of Pseudomonas-induced airway mucus hypersecretory diseases.

Localization of epidermal-type fatty acid binding protein in alveolar macrophages and some alveolar type II epithelial cells in mouse lung.

Almost all alveolar macrophages in the mouse lung were strongly immunoreactive for epidermal-type fatty acid binding protein. At the electron microscope level, the immunoreactive material was localized diffusely in the cytoplasm but not within the nucleus. A certain number of alveolar type II epithelial cells were also immunoreactive for the protein with variable immunointensity, while a substantial number of the type II cells were immunonegative. No immunoreactive interstitial fibroblasts were encountered. Based on the present findings, possible roles of epidermal-type fatty acid binding protein in the host-defence mechanism played by alveolar macrophages are suggested.

Studies on release characteristics and cytotoxicity of 5-fluorouracil loaded polylactide microspheres on lung cancer cell lines

To investigate the release characteristics and cytotoxicity of 5-fluorouracil loaded polylactide microspheres on lung cancer cell lines. The release characteristic of 5-FU-PLA microspheres was detected by constant temperature vibration dialysis assay. The antitumor activities of 5-FU-PLA microspheres against human and mouse lung, gastric and hepatocellular carcinoma cell lines were detected byMTT colorimetric assay. 5-FU-PLA microspheres had a good function of extended-release, its t 1/ 2 was 10. 4 days, and the release process had no blow up effect. The lung and gastric cancer cell lines were more sensitive than hepatocellular cancer cell line to 5-FU-PLA microspheres. The antitumor activity significantly correlated with the time of drug action and the dose of 5-FU released from the microspheres. 5-FU is well distributed in 5-FU-PLA microspheres. Its preparing and releasing processes have no influence on the effect of 5-FU. It can keep the antitumor activities for a relatively long time. The current study provides an experimental basis for interventional therapy of tumors.

Hypermethylation of the p16(Ink4a) promoter in B6C3F1 mouse primary lung adenocarcinomas and mouse lung cell lines: by A.C.Patel, C.H. Anna, J.F.Foley, P.S.Stockton, F.L.Tyson, J.C.Barrett and T.R. devereux

Hypermethylation of the p16(Ink4a) promoter in B6C3F1 mouse primary lung adenocarcinomas and mouse lung cell lines: by A.C.Patel, C.H. Anna, J.F.Foley, P.S.Stockton, F.L.Tyson, J.C.Barrett and T.R. devereux

GATA-6 Activates Transcription of Surfactant Protein A

Surfactant protein A (SP-A) is a member of the collectin family of innate host defense molecules expressed primarily in respiratory epithelial cells of the lung. SP-A concentrations are influenced by both cell-specific and ubiquitous nuclear proteins that regulate SP-A gene transcription in a cell-selective and temporally regulated manner. In this work, a consensus GATA-binding site (GBS) was identified at positions -69 to -64 of the mouse SP-A gene. The transcriptional activity of wild-type SP-A reporter constructs in HeLa cells was increased 5-10-fold when cotransfected with a GATA-6 expression plasmid. Deletion of the GBS completely blocked transactivation by GATA-6. Transfection of a construct expressing GATA-6-engrailed fusion protein inhibited basal expression of the SP-A/chloramphenicol acetyltransferase construct in MLE-15 cells. Nuclear extract proteins from MLE-15 cells bound to the GBS in the mouse SP-A gene, and a supershifted band was detected with a GATA-6-specific antibody. Transactivation of the wild-type SP-A constructs by GATA-6 increased transcriptional activity 7-10-fold, whereas thyroid transcription factor-1 (TTF-1) increased the activity of these constructs 12-18-fold. The effects of cotransactivating with both GATA-6 and TTF-1 expression constructs were additive. However, mutation of the TTF-1-binding sites alone or in combination decreased GATA-6 transactivation. Likewise, mutation of the GBS blocked TTF-1 activation of the SP-A promoter. In situ hybridization demonstrated GATA-6 mRNA in the peripheral epithelial cells of fetal mouse lung, consistent with the sites of SP-A expression. GATA-6 is expressed in respiratory epithelial cells and binds to a cis-acting element in the SP-A gene promoter, activating the transcriptional activity of the gene.

Early emergence of CD8(+) T cells primed for production of type 1 cytokines in the lungs of Mycobacterium tuberculosis-infected mice.

Several lines of evidence suggest that CD8 T cells are important in protection against tuberculosis. To understand the function of this cell population in the immune response against Mycobacterium tuberculosis, T cells from lungs of M. tuberculosis-infected mice were examined by flow cytometry. The kinetics of the appearance of CD8 T cells in lungs of infected mice closely paralleled that of CD4 T cells. Both CD4(+) and CD8(+) T cells displaying an activated phenotype were found in the lungs as early as 1 week postinfection. By 2 weeks, total cell numbers in the lungs had tripled and percentages of T cells were increased two- to threefold; the percentages of CD4(+) T cells were ca. twofold higher than those of CD8(+) T cells. Short-term stimulation with M. tuberculosis-infected antigen-presenting cells induced cytokine production by primed CD4(+) and CD8(+) T cells. Intracellular cytokine staining revealed that 30% +/- 5% of CD4(+) and 23% +/- 4% of CD8(+) T cells were primed for production of gamma interferon (IFN-gamma). However, a difference in in vivo IFN-gamma production by T cells was observed with approximately 12% of CD4(+) T cells and approximately 5% of CD8(+) T cells secreting cytokine in the lungs at any given time during infection. The data presented indicate that although early in infection the majority of IFN-gamma is produced by CD4(+) T cells, cytokine-producing CD8(+) T cells are readily available when triggered by the appropriate stimuli.

Apoptosis induced by Pseudomonas exotoxin: a sensitive and rapid marker for gene delivery in vivo.

The rapid progress in gene therapy has expanded our ability to alter genetic structure, necessitating the development of methods for detecting the activity of new vectors. The central concept of a reporter gene is simple: it is a defined nucleotide sequence, which when introduced into a biological system, yields a readily measurable phenotype on expression. This provides a convenient parameter that is correlated to the molecular events associated with genetic expression. In this study we demonstrate that Pseudomonas exotoxin A (PE) can serve as a sensitive reporter gene to detect gene expression in single cells of mouse lung on cationic liposome delivery of PE-encoding DNA in vivo. Furthermore, we show that PE expression can be detected as early as 2 hr after systemic gene delivery in lungs of recipient mice. We compared PE with the widely used beta-galactosidase gene for this purpose. PE induces apoptosis that can be detected by TdT end labeling of DNA fragments (TUNEL assay) Since few expressed PE molecules are necessary to trigger the apoptosis cascade, the minimal amount of PE-encoding plasmid DNA needed for detection of apoptotic cells after systemic delivery was 0.1 microg per animal compared with at least 1 microg for the beta-galactosidase-encoding plasmid DNA. The maximum number of apoptotic cells detected in lungs was about 15-20 times higher than the maximum number of beta-galactosidase-positive cells. Specificity of apoptosis due to PE expression on delivery of the PE-encoding plasmid was shown by prevention of the apoptotic cascade by the caspase inhibitor Z-VAD-fmk.

INHIBITION OF NATURAL KILLER CELL ACTIVITY IN MICE TREATED WITH TOBACCO SPECIFIC CARCINOGEN NNK

Among the different chemicals present in tobacco and tobacco smoke, 4-(methylnitrosamine)-1-(3-pyridyl)-1-butanone (NNK) is the most potent carcinogen. In the present study the immunosuppressive effect of NNK was investigated in laboratory animals by analyzing the antitumor immune responses. Mice of B6C3F1 strain were treated with different doses of NNK by IP and assayed for natural killer cell activity by the lysis of 51Cr-labeled YAC-1 lymphoma cells. The control mice received physiological saline. The results showed a significant inhibition of natural killer cell activity in the spleen cells of mice treated with 100 or 250 mg/ kg NNK. In contrast to the high-dose NNK group, treatment of mice with lower doses of NNK like 10 or 50 mg/kg had no significant effect on the natural killer cell activity. In addition to spleen, the natural killer cell activity was also suppressed in the hilar lymph nodes and lung cells of NNK-treated mice. The clearance of 125I labeled YAC-1 tumor cells was also reduced from the lungs of mice injected with NNK. Further, the metastatic potential of B16F10 melanoma cells was significantly higher, as evidenced by the increased lung tumor nodules in the high-dose NNK-treated mice. The decreased antitumor immune response in the carcinogen-treated mice was not due to a decrease of NK cells, because flow cytometric analysis indicated no change in the frequency of NK 1.1+ cells between control and treated animals. However, there was an increased plasma cortisone levels in the carcinogen-treated mice compared to control animals. Injection of mice with poly I:C or interleukin-12 was able to restore natural killer cell activity in the tobacco carcinogen-treated mice.

Nickel subsulfide is genotoxic in vitro but shows no mutagenic potential in respiratory tract tissues of BigBlue™ rats and Muta™Mouse mice in vivo after inhalation

Carcinogenic nickel compounds are known to induce promutagenic DNA lesions such as DNA strand breaks and DNA adducts in cultured mammalian cells. In standard mutation assays, in contrast, they were found to be either inactive or weakly active. In our in vitro mutation studies in a lacI transgenic embryonic fibroblast cell line, nickel subsulfide (Ni 3S 2) increased mutation frequency up to 4.5-fold. We subsequently applied the comet assay and transgenic rodent mutation assays to investigate the DNA damaging effect and mutagenic potential of nickel subsulfide in target cells of carcinogenesis. A 2-h in vitro treatment of freshly isolated mouse nasal mucosa and lung cells with nickel subsulfide clearly induced DNA fragmentation in a concentration dependent manner. The strong effect was not seen in the same cell types following inhalative treatment of mice and rats, leading only in the mouse nasal mucosa to high DNA damage. When the same inhalative treatment was applied to lacZ and lacI transgenic mice and rats, the spontaneous mutation frequency of these target genes in the respiratory tissues was not increased. These results support a recently proposed non-genotoxic model of nickel carcinogenesis, which acts through gene silencing via DNA methylation and chromatin condensation. This model may also explain our in vitro mutation data in the lacI transgenic cell line, in which nickel subsulfide increased mutation frequency, but in about one-third of the mutants, molecular analysis did not reveal any DNA sequence change in the coding region of the lacI gene despite of the phenotypic loss of its function.

Selective induction of apoptosis in mouse and human lung epithelial cell lines by the tert-butyl hydroxylated metabolite of butylated hydroxytoluene: a proposed role in tumor promotion

Butylated hydroxytoluene (BHT) causes lung injury in mice and promotes tumor formation. Hydroxylation of a tert-butyl group on BHT to yield the metabolite, 6- tert-butyl-2-[2′-(2′-hydroxymethyl)-propyl]-4-methylphenol (BHTOH), may be required. BHTOH is more potent than BHT on an equimolar basis in causing lung damage, enhancing lung tumor development, killing isolated bronchiolar non-ciliated Clara cells, and inhibiting lung epithelial gap junctional intercellular communication. One mechanism proposed for tumor promoting agents is selective cytotoxicity; killing normal cells allows uninhibited clonal expansion of neighboring initiated cells. We compared the abilities of BHT, BHTOH, and other BHT metabolites to kill non-tumorigenic and tumorigenic mouse and human lung cell lines, and examined the contribution of apoptosis to this cytotoxicity. These cells lack the cytochrome P450 2B isozyme necessary for converting BHT to BHTOH. BHTOH and 4-hydroperoxy-4-methyl-2,6-di- tert-butyl-2,5-cyclohex-adienone (BHTOOH) were most toxic, BHT and 2,6-di- tert-butyl-1,4-benzoquinone (BHTQu) were less potent, and 4-methyl BHT metabolites that are not pneumotoxic were ineffective. BHTOH most strongly induced apoptosis, based on nuclear condensation and transmission electron microscopy. Non-tumorigenic cells were as susceptible to cell death as the neoplastic cell lines when apoptosis and necrosis are not distinguished, but more sensitive to BHTOH-induced apoptosis. An apoptotic mechanism may underlie the lung tumor promoting actions of BHTOH.

Reduction in transforming growth factor-beta type II receptor in mouse lung carcinogenesis.

Transforming growth factor-beta (TGF-beta) is a growth modulator that inhibits the proliferation of many epithelial cells through interaction with its receptors, the type I and type II receptors (TGF-beta RI and RII) by activating their serine/threonine kinase activities. Loss of growth inhibition by TGF-beta is thought to contribute to the development of many types of tumors. To examine the roles of TGF-beta1, -beta2, and -beta3 and TGF-beta RI and RII in chemically induced mouse lung tumorigenesis, we used immunohistochemical and in situ hybridization analyses to measure the expression of their proteins and mRNAs in A/J mice treated with the carcinogen urethane to induce lung adenomas. Immunostaining for the TGF-beta ligands and receptors was detected in the epithelia of the bronchioles of untreated and treated A/J mice at similar levels. Immunostaining for the TGF-beta ligands and receptors was also detected in adenomas by 2 mo. While immunostaining for TGF-beta1, -beta2, and -beta3 and TGF-beta RI in adenomas was detected at levels comparable to those in bronchioles, immunostaining for TGF-beta RII was less intense in adenomas than in bronchioles. Decreased immunostaining for TGF-beta RII in adenomas persisted for at least 8 mo after exposure to urethane, whereas immunostaining for TGF-beta1, -beta2, and -beta3 and TGF-beta RI persisted at levels comparable to those in normal bronchioles. In situ hybridization studies conducted with TGF-beta receptor riboprobes showed a corresponding reduction in expression of TGF-beta RII mRNA but not of TGF-beta RI mRNA in adenomas compared with expression in bronchioles. Expression of TGF-beta RII mRNA was also examined in non-tumorigenic and tumorigenic mouse lung cells; expression of TGF-beta RII mRNA was lower in the tumorigenic cells derived from urethane-induced lung tumors. These data suggest that a decrease in expression of TGF-beta RII may contribute to autonomous cell growth and may play an important role in mouse lung carcinogenesis induced by urethane.

In vitro and in vivo biology of recombinant adenovirus vectors with E1, E1/E2A, or E1/E4 deleted.

Isogenic, E3-deleted adenovirus vectors defective in E1, E1 and E2A, or E1 and E4 were generated in complementation cell lines expressing E1, E1 and E2A, or E1 and E4 and characterized in vitro and in vivo. In the absence of complementation, deletion of both E1 and E2A completely abolished expression of early and late viral genes, while deletion of E1 and E4 impaired expression of viral genes, although at a lower level than the E1/E2A deletion. The in vivo persistence of these three types of vectors was monitored in selected strains of mice with viral genomes devoid of transgenes to exclude any interference by immunogenic transgene-encoded products. Our studies showed no significant differences among the vectors in the short-term maintenance and long-term (4-month) persistence of viral DNA in liver and lung cells of immunocompetent and immunodeficient mice. Furthermore, all vectors induced similar antibody responses and comparable levels of adenovirus-specific cytotoxic T lymphocytes. These results suggest that in the absence of transgenes, the progressive deletion of the adenovirus genome does not extend the in vivo persistence of the transduced cells and does not reduce the antivirus immune response. In addition, our data confirm that, in the absence of transgene expression, mouse cellular immunity to viral antigens plays a minor role in the progressive elimination of the virus genome.

Measurement and characterization of micronuclei in cultured primary lung cells of mice following inhalation exposure to benzene.

The genotoxic effects of benzene in lung cells of mice exposed to single acute doses by inhalation have been estimated by cytogenetic analysis of micronuclei in primary cultures of lung fibroblasts. Mice were nose-only exposed to 1000 p.p.m. for 30 or 60 min or to 3500 p.p.m. for 30 min and sacrificed 24 h after the end of exposure. Lung fibroblasts were cultured attached to coverslips for 72 h, the last 48 h in the presence of 0.75 microgram/ml cytochalasin B. Micronuclei were scored in binucleate cells. The mechanism(s) of micronucleus induction was characterized by immunofluorescent staining of kinetochore proteins (CREST staining), which allowed micronuclei due to chromosome loss (kinetochore-positive) to be distinguished from those produced by chromosome breakage (kinetochore-negative). Three- and 4-fold statistically significant increases in total micronucleus frequencies were observed in all benzene-exposed mice with respect to unexposed controls. The effect was neither concentration nor time dependent. This is compatible with a plateau dose-effect relationship for the effects on bone marrow, which is explained by saturation of metabolism. Both chromosome loss and chromosome breakage appear to contribute to micronucleus formation, suggesting that in addition to chromosome rearrangements, aneuploidy may be a relevant early genotoxic event associated with benzene carcinogenicity. Under the same treatment conditions no micronucleus induction could be shown in spleen lymphocytes, suggesting that with very short benzene exposures cells at the first contact site with local metabolizing capacity have a higher probability of genetic alterations potentially leading to neoplasia.

Thymosin beta15 expression in tumor cell lines with varying metastatic potential.

We previously isolated thymosin beta15 from highly metastatic Dunning rat prostatic carcinoma cells. Immunohistochemical study of human prostate cancer specimens revealed a general correlation between Gleason grade and thymosin beta15 expression, with high-grade (more malignant) tumors showing increased staining compared to low-grade tumors. To determine whether thymosin beta15 may be differentially expressed in cancer cells with different metastatic potential other than in the prostatic carcinoma cells, we examined thymosin beta15 mRNA levels in tumor cell lines from different species. We also examined thymosin beta15 protein levels in human breast cancer samples. Thymosin beta15 was upregulated in the highly metastatic mouse lung and human breast cancer cell lines in comparison to the nonmetastatic counterparts. Immunohistochemical staining showed the evidence of upregulation of thymosin beta15 in malignant human breast carcinomas as compared to benign breast tumors. The expression of thymosin beta15 was correlated with the metastatic potential of the mouse lung carcinoma and human breast carcinoma cells in addition to the prostatic carcinomas. Thymosin beta15 may be a useful marker to predict metastatic potential of certain human cancers.

Transforming Growth Factor-Beta Expression in Mouse Lung Carcinogenesis

Transforming growth factor-beta (TGF-β) is a multifunctional growth modulator that inhibits the proliferation of many epithelial cells while stimulating the proliferation of most fibroblasts. To examine the role of TGF-β in mouse lung chemically induced tumorigenesis, expression of the TGF-β1, -β2, and -β3 proteins was examined in A/J mice treated with the carcinogen urethane to induce lung adenomas using immunohistochemical staining analysis. Immunostaining for the TGF-β ligands was detected in the epithelium of the bronchioles of untreated A/J mice with immunostaining being more intense for TGF-β1 than for TGF-β2 and TGF-β3; immunostaining for each TGF-β ligand was also detected in the bronchiolar epithelium of urethane-treated A/J mice at levels similar to untreated mice. Immunostaining for the TGF-β ligands was also detected in adenomas by 2 months; staining for TGF-β1, -β2, and -β3 in adenomas was detected at levels comparable with bronchioles. Following treatment with urethane for 8 months, immunostaining for TGF-βs 1, 2, and 3 in bronchioles persisted at levels comparable to that in normal bronchioles and also persisted in adenomas, with staining for the TGF-β ligands being very prominent on the edge of the tumor. Expression of TGF-β1 mRNA was examined in urethane-treated mouse lung tissue using Northern blot hybridization; here, expression of TGF-β1 mRNA increased 2-fold in 3-month urethane-treated lung tissue and an additional 2.5-fold by 8 months following urethane administration. Expression of TGF-β1 mRNA was also examined in nontumorigenic and tumorigenic mouse lung cells; in these cells, expression of TGF-β1 mRNA was higher in the tumorigenic cells than in the nontumorigenic cell line. These data show that there is an increase in expression of TGF-β1 during tumorigenesis and suggest that TGF-β may play an important role in mouse lung carcinogenesis induced by urethane.

Alveolar macrophages regulate the induction of primary cytotoxic T-lymphocyte responses during influenza virus infection.

Virus-specific cytotoxic T lymphocytes (CTL) are thought to be responsible for the eradication of respiratory influenza virus infections by direct cytolysis of virus-infected epithelial cells. In this study, we provide evidence for a role for alveolar macrophages (AM) in the regulation of pulmonary virus-specific CTL responses. Prior to infection with influenza virus, AM were selectively eliminated in vivo with a liposome-mediated depletion technique, and virus-specific CTL activities of lung and mediastinal lymph node (MLN) cells were assayed ex vivo and compared with those for normal mice. AM depletion resulted in increased primary CTL responses and changed the kinetics of the CTL response. Flow cytometric analysis of lung and MLN cells showed that the percentage of CD8+ cells was not altered after AM depletion and that lung cells from AM-depleted mice had an increased capacity to lyse virus-infected cells. Upon restimulation in vitro, virus-specific CTL activity in lung cells of normal mice was similar to that in lung cells of AM-depleted mice. Furthermore, elimination of AM resulted in increased virus titers in the lung, but virus clearance as a function of time was not affected. Our results show that AM regulate virus-specific CTL responses during respiratory influenza virus infection by removing viral particles, by downregulating the priming and activity of CTL in MLN cells, and by inhibiting the expansion of virus-specific CTL in the lung.

Estimation of the spatial distribution of target cells for radiation pneumonitis in mouse lung

Purpose : Recent studies of Liao et al. and Travies et al. have demonstrated that irradiation of cross-sectional partial volumes contiguous to the base of mouse lung produces a higher incidence of pneumonitis than irradiation of equally sized subvolumes contigous to the apex. One interpreation of this finding is that the critical target cells for pneumonitis are not distributed uniformly throughout the lung. The purpose of the present study was to test this interpretation by obtaining an estimate of the spatial distribution of the critical target cells for pneumonitis in mouse lung, based on the partial-volume data. Methods and Materials : A mathematical models was derived describing the probability of radiation pneumonitis as a function of dose, volume of lung irradiated, and location in the lung of the irradiated subvolume. The model includes a nonparametric description of the spatial target-cell distribution in lung, to be estimated from data. The models was fitted to the lethality data of Liao et al. and Travis et al. to obtain estimates of the proportion of target cells contained in each of various subvolumes of the lung. Results : The results indicate that the critical target cells in mouse lung are concentrated in the base and, to a somewhat lesser extent, in the apex of the lung, with fewer cells in the middle region. The estimated spatial distribution of target cells in mouse lung agrees well with the distribution of alveoli, whose concentration in the lidlung is limited by the present of the major conducting airways. Conclusion : Heterogeneity in the spatial distribution of critical target cells in normal tissue implies that the complication probability (NTCP) depends on the location in the organ of the irradiated subvolume, as well as on radiation dose and subvolume size. Calculations using an NTCP model for mouse lung indicate that irradiation of equal subvolumes of lung with the same dose can lead to complication probabilities covering the full range from 0 to 100%, depending only onthe location in the lung of the irradiated subvolume.

Intermediate TCR cells in mouse lung: their effector function to induce pneumonitis in mice with autoimmune-like graft-versus-host disease.

The lung comprises lymphocytes even under noninflammatory conditions. We investigated the presence of NK cells, extrathymic T cells, and thymus-derived T cells in this organ. As shown previously in mouse liver, two-color staining for CD3 and IL-2R beta-chain (IL-2Rbeta) identifies CD3- IL-2Rbeta+ NK cells, CD3int IL-2Rbeta+ cells (int indicates intermediate; of extrathymic origin), and CD3high IL-2Rbeta- cells (high indicates high; of thymic origin). These populations were present in the lungs of normal mice in a unique manner (i.e., NK cells > CD3high cells > CD3int cells). The proportion of CD3int cells increased in the lung with age. In athymic mice, only CD3int cells were detected in the lung. In contrast to CD3int cells in the liver, the majority of these cells in the lung did not express NK1.1 Ags. Other properties of CD3int cells in the lung were the same as those in the liver, e.g., double-negative CD4- 8- cells and gammadelta T cells. CD3int cells in the lung contained forbidden clones similar to those in other organs. When (B6 x bm12) F1 mice (Ly5.2) were injected with CD3high cells of B6-Ly5.1 origin, F1 mice fell victim to chronic graft-vs-host disease and pneumonitis, showing the expansion of CD3int cells. Almost all of them were of recipient origin (Ly5.2+). More importantly, such CD3int cells induced autoimmune-like pneumonitis when injected into irradiated F1 mice. CD3int cells isolated from the lung in mice with graft-vs-host disease exerted autologous cytotoxicity against thymocytes in vitro. These results suggest that extrathymic T cells exist in the lung and that their expansion may be responsible for inflammatory lung diseases.

Inhibition of lung tumor cell growth in vitro and mouse lung tumor formation by lovastatin

The HMG-CoA reductase inhibitor, lovastatin (LOV), has been reported to inhibit Ras farnesylation and the growth of Ras-transformed cells. Mouse lung tumors and human lung adenocarcinomas often have activating mutations in K-ras alleles. In the present study, we determined whether LOV inhibited the growth in vitro of mouse (C10, E9, LM1, LM2, and 82-132) and human (NCl-H125, H292, H441, H460, and H661) nor-transformed and neoplastically transformed lung epithelial cells and whether growth inhibition was related to cell transformation or K-ras activation. LOV inhibited the growth of mouse and human lung cells, but cell sensitivities were unrelated to neoplastic transformation or K-ras mutation. In addition, we evaluated whether LOV could inhibit the formation of lung adenomas induced by the tobacco-specific nitrosamine, 4-(N-methyl-N-nitrosamino)-1-(3-pyridyl)-1-butanone (NNK) in mice. LOV was administered in the diet at 0, 40, 160, or 400 ppm ad libitum to male strain A/J mice beginning 1 week after lung tumor induction with NNK (10 mumol/mouse). Mice were euthanized 6 months later. Enumeration of lung tumors revealed that LOV did not affect tumor incidence or size, but significantly reduced tumor multiplicity in a dose-related manner. These data suggest that LOV can suppress the formation of NNK-induced lung tumors, possibly at an early promotional stage. This suppression does not appear to be related to either the presence of mutated K-ras or to changes in K-ras expression.

Role of viral antigens in destructive cellular immune responses to adenovirus vector-transduced cells in mouse lungs.

Adenoviruses missing E1 have been used as gene delivery vectors to the lungs for the treatment of cystic fibrosis. Transient expression of the recombinant gene and the development of inflammation have been two major limitations to the application of first-generation recombinant adenoviruses for gene therapy. Studies with mouse models of liver- and lung-directed gene therapy suggested that CD8+ cytotoxic T lymphocytes (CTLs) are effectors that contribute to extinction of transgene expression. The precise antigens responsible for activation of CTLs have not been identified. In this study, we examine the relative contributions of viral proteins versus the transgene product to the activation of CTLs which eliminate transgene-containing cells in mouse lungs. Instillation of a lacZ-expressing virus into the lungs of C57BL/6 mice elicited CTL responses to both viral proteins and the transgene product, beta-galactosidase, which collectively contribute to loss of trans-gene expression in mouse airways. Similar results were obtained in two experimental models in which the animals should be tolerant to the transgene, i.e., lacZ virus delivered to an animal transgenic for lacZ and a virus expressing the liver-specific enzyme ornithine transcarbamylase administered to the lungs of various strains of immune-competent mice. These data confirm the hypothesis that CTLs specific for viral antigens contribute to the problem of transgene instability in mouse lungs and indicate that CTLs specific for transgene product alone cannot account for the observed problem.