Type I interferon induces inhibitory 16-kD CCAAT/ enhancer binding protein (C/EBP)beta, repressing the HIV-1 long terminal repeat in macrophages: pulmonary tuberculosis alters C/EBP expression, enhancing HIV-1 replication.

We have previously observed that HIV-1 replication is suppressed in uninflamed lung and increased during tuberculosis. In vitro THP-1 cell-derived macrophages inhibited HIV-1 replication after infection with Mycobacterium tuberculosis. Suppression of HIV-1 replication was associated with inhibition of the HIV-1 long terminal repeat (LTR) and induction of ISGF-3, a type I interferon (IFN)-specific transcription factor. Repression of the HIV-1 LTR required intact CCAAT/enhancer binding protein (C/EBP) sites. THP-1 cell-derived macrophages infected with M. tuberculosis, lipopolysaccharide, or IFN-beta induced the 16-kD inhibitory C/EBPbeta isoform and coincidentally repressed HIV-1 LTR transcription. C/EBPbeta was the predominant C/EBP family member produced in THP-1 macrophages during HIV-1 LTR repression. In vivo, alveolar macrophages from uninflamed lung strongly expressed inhibitory 16-kD C/EBPbeta, but pulmonary tuberculosis abolished inhibitory C/EBPbeta expression and induced a novel C/EBP DNA binding protein. Therefore, in vitro, proinflammatory stimulation produces an IFN response inhibiting viral replication by induction of a C/EBPbeta transcriptional repressor. THP-1 cell-derived macrophages stimulated with type I IFN are similar to alveolar macrophages in the uninflamed lung in vivo. In contrast, the cellular immune response in active pulmonary tuberculosis disrupts this innate immunity, switching C/EBP expression and allowing high level viral replication.

Mycobacterium tuberculosis induces CCL18 expression in human macrophages.

The interaction of Mycobacterium tuberculosis (MTB) with the immune system is mediated by cytokine and chemokine responses of macrophages and/or dendritic cells. Chemokine (C-C motif) ligand 18 (CCL18) and interleukin (IL)-10 are major factors secreted by phagocytes, postulated to recruit naïve T lymphocytes and inhibit pro-inflammatory cells. Our study investigated the role of CCL18 and IL-10 in an in vitro model of infection by MTB in human macrophages. CD14(+) monocytes, obtained from the peripheral blood of eight healthy donors, differentiated in monocyte-derived macrophages (MDM) with monocyte-colony stimulating factor (100 ng/ml) for 6 days, were stimulated in vitro with lipopolysaccharide (LPS) (1 microg/ml) and with heat killed MTB Hv37Ra (multiplicity of infection 1:5) for 24 h. Alveolar macrophages from five healthy donors were infected with MTB Hv37RA. CCL18 protein and mRNA were detected by enzyme-linked immunosorbent assay (ELISA) and real-time PCR, IL-10 levels by ELISA. Stimulation of MDM with LPS or MTB led to a significant increase in CCL18 protein (control 2.67 +/- 0.46 ng/ml, LPS 4.05 +/- 0.56 ng/ml, with MTB 6.70 +/- 1.59 ng/ml, n = 5, P < 0.05) and specific mRNA levels (control 0.09 +/- 0.01, LPS 0.24 +/- 0.11, with MTB 0.34 +/- 0.08 CCL18/Glyceraldehyde 3-phosphate dehydrogenase (GAPDH), n = 3, P < 0.05). A significant increase of the production of CCL18 was observed in infected alveolar macrophages. IL-10 levels increased from 38.52 +/- 26.38 pg/ml in control cells to 1129.32 +/- 235.00 and 974.25 +/- 164.46 pg/ml in LPS and MTB treated cells, respectively (P < 0.05). Up-regulation of CCL18 and IL-10 in macrophages by MTB may be involved in the recruitment of naïve T cells in association with local suppressive immunity against intracellular pathogens. This could represent a mechanism of tolerance during the early phases of infection.

Mycobacterium tuberculosis enhances human immunodeficiency virus-1 replication by transcriptional activation at the long terminal repeat.

Tuberculosis has emerged as an epidemic fueled by the large number of individuals infected with the human immunodeficiency virus, especially those who are injecting drug users. We found a striking increase from 4- to 208-fold in p24 levels in bronchoalveolar lavage fluid from involved sites of Mycobacterium tuberculosis infection vs uninvolved sites in three HIV+ patients. We used an in vitro cell culture model to determine if tuberculosis could activate replication of HIV-1. Mononuclear phagocyte cell lines U937 and THP-1 infected with HIV-1JR-CSF, in vitro and stimulated with live M. tuberculosis H37Ra, had a threefold increase in p24 in culture supernatants. Using the HIV-1 long terminal repeat with a chloramphenicol acetyltransferase (CAT) reporter construct, live M. tuberculosis increased transcription 20-fold in THP-1 cells, and cell wall components stimulated CAT expression to a lesser extent. The nuclear factor-kappa B enhancer element was responsible for the majority of the increased CAT activity although two upstream nuclear factor-IL6 sites may also contribute to enhanced transcription. Antibodies to TNF-alpha and IL-1 inhibited the increase in CAT activity of the HIV-1 long terminal repeat by M. tuberculosis from 21-fold to 8-fold. Stimulation of HIV-1 replication by M. tuberculosis may exacerbate dysfunction of the host immune response in dually infected individuals.

Mechanisms of stimulation of interleukin-1 beta and tumor necrosis factor-alpha by Mycobacterium tuberculosis components.

The granulomatous immune response in tuberculosis is characterized by delayed hypersensitivity and is mediated by various cytokines released by the stimulated mononuclear phagocytes, including tumor necrosis factor-alpha (TNF alpha) and IL-1 beta. We have demonstrated that Mycobacterium tuberculosis cell wall component lipoarabinomannan (LAM), mycobacterial heat shock protein-65 kD, and M. tuberculosis culture filtrate, devoid of LPS as assessed by the Amebocyte Lysate assay, stimulate the production of TNF alpha and IL-1 beta proteins and mRNA from mononuclear phagocytes (THP-1 cells). The effect of LAM on the release of these cytokines was specific, as only LAM stimulation was inhibited by anti-LAM monoclonal antibody. Interestingly, we found that LAM and Gram-negative bacterial cell wall-associated endotoxin LPS may share a similar mechanism in their stimulatory action as demonstrated by inhibition of TNF alpha and IL-1 beta release by monoclonal antibodies to CD14. Anti-CD14 monoclonal antibody MY4 inhibited both TNF alpha and IL-1 beta release with LAM and LPS but no effect was observed with other mycobacterial proteins. An isotype antibody control did not inhibit release of cytokines under the same experimental conditions. M. tuberculosis and its components upregulated IL-1 beta and TNF alpha mRNAs in THP-1 cells. Nuclear run-on assay for IL-1 beta demonstrated that LAM increased the transcription rate. The induction of IL-1 beta was regulated at the transcriptional level, in which these stimuli acted through cis-acting element(s) on the 5' flanking region of the IL-1 beta genomic DNA. M. tuberculosis cell wall component LAM acts similarly to LPS in activating mononuclear phagocyte cytokine TNF alpha and IL-1 beta release through CD14 and synthesis at the transcriptional level; both cytokines are key participants in the host immune response to tuberculosis.

Alveolar macrophages release an insulin-like growth factor I-type molecule.

Human alveolar macrophages, when activated, release a progression-type growth factor for fibroblasts that signals "competent" fibroblasts to replicate. The present study demonstrates that this growth activity is an insulin-like growth factor I (IGF-I)-type molecule. Partial purification of medium conditioned by activated alveolar macrophages using ion exchange and gel filtration chromatography revealed an IGF-I molecule as detected by an anti-IGF-I polyclonal antibody and that the specific activity of the progression-type growth activity tracked with the amount of IGF-I present. In a serum-free complementation test, the increase in fibroblast proliferation by alveolar macrophage IGF-I was reduced in a dose-response manner with an anti-IGF-I monoclonal antibody. The alveolar macrophage IGF-I displaced 125I-IGF-I from its receptor in a binding assay utilizing human lung fibroblasts and it stimulated type I IGF receptors purified from human lung fibroblasts to phosphorylate a tyrosine-containing artificial substrate. In contrast to the 7.6-kD serum IGF-I, gel chromatography revealed that the alveolar macrophage IGF-I had an apparent molecular mass of 26 kD, similar to other tissue IGF-Is. Alveolar macrophages expressed IGF-I mRNA transcripts as detected by solution hybridization using a 32P-labeled riboprobe complementary to exons I-II-III of the IGF-I gene. In the context of the known functions of the family of IGF-I molecules in cell growth, IGF-I released by activated alveolar macrophages may play a role in acute and chronic inflammatory disorders.

Enhanced interleukin-8 release and gene expression in macrophages after exposure to Mycobacterium tuberculosis and its components.

Mycobacterium tuberculosis infection is accompanied by acute and chronic inflammatory infiltrates associated with necrotizing granulomas in lung tissue. The cellular infiltrate is characterized by inflammatory cells which include neutrophils, lymphocytes, and macrophages. In animal and in vitro models of mycobacterial infection, cytokines including tumor necrosis factor-alpha (TNF-alpha), interferon gamma (IFN-gamma), and interleukin-1 beta (IL-1 beta) participate in granulomatous inflammation. We hypothesized that interleukin-3, a potent chemoattractant for neutrophils and lymphocytes, could be released by activated alveolar macrophages after exposure to M. tuberculosis or its components and contribute to granulomatous lung inflammation. A quantitative immunoassay revealed that IL-8 protein release was significantly elevated in supernatants of macrophages and in lavage fluid obtained from patients with pulmonary tuberculosis compared to normal controls. In addition, Northern blots demonstrated striking up-regulation of IL-8 mRNA in macrophages from these patients. M. tuberculosis and its cell wall components lipoarabinomannan (LAM), lipomannan (LM), and phosphoinositolmannoside (PIM) stimulated IL-8 protein release and mRNA expression in vitro from alveolar macrophages, but deacylated LAM did not. Neutralizing antibodies to TNF-alpha and/or IL-1-alpha and beta blocked 83% of the stimulation. IL-8 synthesis and release is an early response of macrophages after phagocytosis of M. tuberculosis. Its production serves to attract both acute and chronic inflammatory cells of active infection and thus participates in the process of containment of the pathogen.

Acute tropical pulmonary eosinophilia. Characterization of the lower respiratory tract inflammation and its response to therapy.

Although acute tropical pulmonary eosinophilia (TPE) is well recognized as a manifestation of filarial infection, the processes that mediate the abnormalities of the lung in TPE are unknown. To evaluate the hypothesis that the derangements of the lower respiratory tract in this disorder are mediated by inflammatory cells in the local milieu, we utilized bronchoalveolar lavage to evaluate affected individuals before and after therapy. Inflammatory cells recovered from the lower respiratory tract of individuals with acute, untreated TPE (n = 8) revealed a striking eosinophilic alveolitis, with marked elevations in both the proportion of eosinophils (TPE 54 +/- 5%; normal 2 +/- 5%; P less than 0.001) and the concentration of eosinophils in the recovered epithelial lining fluid (ELF) (TPE 63 +/- 20 X 10(3)/microliter; normal 0.3 +/- 0.1 X 10(3)/microliter; P less than 0.01). Importantly, when individuals (n = 5) with acute TPE were treated with diethylcarbamazine (DEC), there was a marked decrease of the lung eosinophils and concomitant increase in lung function. These observations are consistent with the concept that at least some of the abnormalities found in the lung in acute TPE are mediated by an eosinophil-dominated inflammatory process in the lower respiratory tract.

Early responses to infection: chemokines as mediators of inflammation.

Chemokines are a superfamily of small related protein molecules that are secreted by a variety of cells and that have, among their diverse biological properties, the ability to recruit a wide range of immune cells to the sites of infection and disease. Chemokines are secreted in response to bacterial, viral, parasitic, and mycobacterial pathogens. Our recent progress in understanding the patterns of chemokine secretion in response to various pathogens and their impact on disease manifestations is likely to lead to the development of novel therapeutic approaches for a variety of serious infections.

Regulation of the interleukin-1 beta (IL-1 beta) gene by mycobacterial components and lipopolysaccharide is mediated by two nuclear factor-IL6 motifs.

The cytokines interleukin-1 beta (IL-1 beta) and tumor necrosis factor alpha (TNF-alpha) are released by mononuclear phagocytes in vitro after stimulation with mycobacteria and are considered to mediate pathophysiologic events, including granuloma formation and systemic symptoms. We demonstrated that the Mycobacterium tuberculosis cell wall component lipoarabinomannan (LAM) is a very potent inducer of IL-1 beta gene expression in human monocytes and investigated the mechanism of this effect. We localized the LAM-, lipopolysaccharide (LPS)-, and TNF-alpha-inducible promoter activity to a -131/+15 (positions -131 to +15) DNA fragment of the IL-1 beta gene by deletion analysis and chloramphenicol acetyltransferase assay. Within this DNA fragment, there were two novel 9-bp motifs (-90/-82 and -40/-32) with high homology to the nuclear factor-IL6 (NF-IL6) binding site. Site-directed mutagenesis demonstrated that the two NF-IL-6 motifs could be independently activated by LAM, LPS, or TNF-alpha and that they acted in an orientation-independent manner. DNA mobility shift assay revealed specific binding of nuclear protein(s) from LAM-, LPS-, or TNF-alpha-stimulated THP-1 cells to the NF-IL6 motifs. We conclude that the two NF-IL6 sites mediate induction of IL-1 beta in response to the stimuli LAM, LPS, and TNF-alpha.

Modification of the p53 transgene of a replication-competent adenovirus prevents mdm2- and E1b-55kD-mediated degradation of p53.

Clinical efficacy of adenovirus-mediated cancer gene therapy has been limited thus far. To improve its oncolytic effect, a replication-competent adenoviral vector was previously constructed to express high levels of p53 at a late time point in the viral life cycle. p53 expression from this vector improved tumor cell killing and viral spread in vitro. However, p53 function is antagonized by cellular mdm2 and adenoviral E1b-55kD, both of which are known to bind to and inactivate p53. Therefore, a new vector (Adp53W23S) that expresses a modified p53 transgene, which does not bind to E1b-55kd and mdm2, was constructed. The modified p53 protein was demonstrated to have a substantially prolonged half-life, and its localization was predominantly nuclear. Viral replication was unaffected by expression of the modified p53 and cancer cell killing was improved in vitro. However, in a xenograft model, efficacy was not significantly different from control virus. In conclusion, expression of a degradation-resistant p53 transgene late in the life cycle of a replication-competent adenovirus improves p53 stability and cancer cell killing in vitro. However, other factors, such as the adenoviral E1b-19kD and E1a proteins, which oppose p53 function, and limitations to viral spread need to be addressed to further improve in vivo efficacy.

Prevalence of workplace exacerbation of asthma symptoms in an urban working population of asthmatics.

OBJECTIVES: We used an interviewer-administered questionnaire to investigate workplace exacerbation of asthma symptoms (WEAS) among low-income, minority, working asthmatics admitted Bellevue Hospital Center in New York City from 2001 to 2002. We hypothesized that a high prevalence of WEAS would be found in this population among all jobs held and a subset of individual occupational classifications. MEASUREMENTS AND MAIN RESULTS: Of 301 subjects, 51% reported WEAS in their current or most recent job; 71% reported WEAS in any job. Prevalences (95% confidence intervals) of WEAS in common job classifications were 61% (49-73%) in janitorial jobs, 50% (33-67%) in garment and textile manufacturing jobs, and 38% (23-55%) in construction jobs. CONCLUSION: WEAS is prevalent in this urban minority population.

Detection of K-ras oncogene mutations in bronchoalveolar lavage fluid for lung cancer diagnosis.

BACKGROUND: Lung cancer is the leading cause of cancer deaths in the United States. A long-standing goal of cancer researchers has been to develop tests that would facilitate earlier diagnosis and treatment of lung cancer and thereby decrease mortality from this disease. Because cancer results from the accumulation of a variety of genetic events (e.g., mutations, rearrangements, and deletions) in genes controlling cell growth and differentiation, these changes might serve as diagnostically useful molecular markers. Activation of the K-ras oncogene by point mutations in codon 12, which occurs in many cases of lung adenocarcinoma, may serve as one such clinically useful molecular marker. For detection of K-ras point mutations in bronchoalveolar lavage fluid, in which small numbers of malignant cells are mixed with a population of predominantly genetically normal cells, the sensitivity of commonly used assays for ras mutations risks false-negative results. PURPOSE: By applying a highly sensitive assay, we investigated whether detection of K-ras codon 12 mutations in samples of bronchoalveolar lavage fluid could be clinically useful in diagnosing lung cancer. METHODS: We developed a highly sensitive assay for detecting K-ras codon 12 mutations based on an enriched polymerase chain reaction (PCR) technique. This technique was applied to 87 specimens of bronchoalveolar lavage fluid specimens that were obtained from 86 patients, and associated tumor biopsy specimens obtained from 35 of these patients who underwent diagnostic bronchoscopy for clinically suspected lung cancer. Statistical comparisons were performed by using the two-tailed Fisher's exact test [corrected]. RESULTS: Of 52 patients with confirmed lung cancer, samples of bronchoalveolar lavage fluid from 16 patients contained K-ras codon 12 mutations, including 14 (56%) of 25 patients with lung adenocarcinomas, one (33%) of three with bronchoalveolar carcinomas, one (20%) of five with large-cell carcinomas, and none of the 14 with squamous cell carcinomas. Mutations were detected in four additional cases in which cancer was suspected but had not been histologically confirmed. Tissue samples from 35 of the patients all yielded the identical K-ras codon 12 genotype found in the corresponding samples of bronchoalveolar lavage fluid. No mutation was found in any sample from 30 patients with diagnoses other than non-small-cell lung cancer. Thus, for those cases in which tissue was available and tested, the sensitivity and specificity of detecting K-ras mutations in bronchoalveolar lavage fluid for diagnosing K-ras mutation-positive lung cancer were both 100%. For nine patients, K-ras mutations were detected in bronchoalveolar lavage fluid obtained during otherwise nondiagnostic bronchoscopies. CONCLUSIONS: Our data demonstrate that sensitive detection of K-ras codon 12 mutations can serve as an important adjunct to cytology in the diagnosis of lung cancer. IMPLICATIONS: Detection of these mutations could lead to earlier cancer diagnosis and less need for invasive diagnostic procedures.

Sister chromatid exchange frequency in asbestos workers.

In vitro cytogenetic studies of amosite, chrysotile, and crocidolite asbestos have shown that these fibers may induce chromosome abnormalities and an elevated sister chromatid exchange (SCE) rate in mammalian cells. Twenty-five asbestos insulators (6 with radiographic asbestosis) were compared to 14 controls frequency matched for age and were found to have a marginally increased SCE rate in circulating lymphocytes with increasing years of exposure (P= 0.057). There was a significant association between SCE rate and smoking (P=0.002) after controlling for years of asbestos exposure and age. Smoking asbestos insulators had the highest SCE rate. Sister chromatid exchanges in chromosomes of group A, i.e., the group with the longest chromosomes, were significantly associated with asbestos exposure and cigarette smoking, with an interaction between the two.

Increased prevalence of K-ras oncogene mutations in lung adenocarcinoma.

Reported estimates of ras mutation prevalence in lung adenocarcinoma of 15-24% may be underestimates because of the insensitivity of the assays used. We have devised a rapid, non-radioactive assay for ras mutations, which detects 1 mutant allele/10(3) normal alleles and have used it to study DNA isolated from 53 lung tumor samples (including 28 adenocarcinomas) previously analyzed by PCR/allele specific oligonucleotide hybridization, which is less sensitive. We detected mutations in 13 of 28 samples, including 7 not detected by PCR/allele specific oligonucleotide hybridization. We also found ras mutations in 14 of 25 previously unstudied samples (56%). Our results indicate that the prevalence of K-ras codon 12 mutations in lung adenocarcinoma is higher than previously reported; thus, ras mutations may be more clinically useful as molecular markers for lung cancer than has been appreciated.

Normal human mesothelial cells and mesothelioma cell lines express insulin-like growth factor I and associated molecules.

Insulin-like growth factor (IGF) I has important growth regulatory functions in normal growth and development. IGF-I is also a mitogen for a number of cancer cell lines; however, its autocrine effect has not been well established. In this study, the expression of IGF-I, its receptor, and its major serum-binding protein were examined in 5 normal human mesothelial (NHM) cell samples and 11 pleural mesothelioma cell lines. All NHM cells and mesothelioma cell lines expressed IGF-I, IGF-binding protein 3 (IGFBP-3), and IGF-I receptor mRNA by either Northern blot or reverse transcription polymerase chain reaction analysis. IGF-I (0.136 +/- 0.024 ng/ml, mean +/- SEM) and IGFBP-3 (18.5 +/- 3.2 ng/ml) proteins were readily detected in the conditioned medium of mesothelioma cell lines but were not greater than corresponding measurements in that of NHM cells (IGF-I, 0.120 +/- 0.080 ng/ml; IGFBP-3, 15.9 +/- 1.3 ng/ml). Exogenous recombinant IGF-I stimulated cell proliferation of NHM cells, demonstrating the presence of a functional IGF-I receptor. Our results suggest that IGF-I may function as an autocrine growth stimulus in normal proliferating mesothelial cells, which may contribute to their malignant transformation.

Inhibition of anchorage-independent growth and lung metastasis of A549 lung carcinoma cells by IkappaBbeta.

To evaluate the role of the NF-kappaB signaling pathway in oncogenic transformation, we expressed IkappaBbeta, a specific inhibitor of NF-kappaB, in two human lung adenocarcinoma cell lines, A549 and H441. Expression of IkappaBbeta significantly reduced NF-kappaB activation induced by cotransfection with p65/RelA or TNF-alpha and abrogated the basal NF-kappaB activity in A549 cells. Transfection of IkappaBbeta into A549, H441 and K-ras-transformed NIH3T3 cells suppressed anchorage-independent growth as measured by colony formation in soft agar. Anchorage-independent growth of vector-transfected A549 cells in reduced serum could be enhanced by both EGF and IGF-I. In contrast, only EGF but not IGF-I could induce anchorage-independent growth of IkappaBbeta-expressing A549 cells, suggesting that the IGF-I signaling pathway regulating growth and survival may be blocked by IkappaBbeta. Interestingly, expression of IkappaBbeta suppressed growth of A549 cells in low serum in vitro without affecting in vivo growth subcutaneously in nude mice. However, metastatic growth of IkappaBbeta-expressing A549 cells in the lungs of nude mice was significantly inhibited. These results provide evidence that NFkappaB plays an important role in anchorage-independent growth and metastatic growth of lung carcinoma cells.

Induction of tumor suppression and glandular differentiation of A549 lung carcinoma cells by dominant-negative IGF-I receptor.

Overexpression or activation of insulin-like growth factor I receptor (IGF-IR) has been observed in many human cancers including breast, lung, colon and gastric carcinomas. We demonstrate that inhibition of the endogenous insulin-like growth factor I receptor by stable expression of a dominant-negative IGF-IR represses the transforming activity in vitro and tumorigenicity of human lung carcinoma cells A549 in vivo. The suppression of tumorigenicity in nude mice is correlated with the induction of glandular differentiation. In addition, functional inhibition of the endogenous receptor dramatically increases the sensitivity of A549 cells to a variety of apoptotic signals including UV irradiation and proteasome inhibitors. These effects are due to the formation of a stable heterocomplex of the dominant-negative receptor with the endogenous wild type receptor which reduces the kinase activity of the latter by twofold. Thus, inhibition of the IGF-IR signaling pathway not only suppresses tumorigenicity but also enhances sensitivity to apoptosis-inducing agents. Antagonizing IGF-IR signaling by promoting tumor differentiation and enhancing sensitivity to apoptotic death are potential cancer therapeutic approaches.

Role of c-Jun N-terminal kinase 1 (JNK1) in cell cycle checkpoint activated by the protease inhibitor N-acetyl-leucinyl-leucinyl-norleucinal.

The cysteine protease inhibitor N-acetyl-leucinyl-leucinyl-norleucinal (LLnL) inhibited the growth of the Calu-1 lung carcinoma cells and induced a prolonged cell cycle arrest in the S phase. c-Jun N-terminal kinases (JNKs) participate in cellular responses to mitogenic stimuli, environmental stresses, and apoptotic signals but its role in cell cycle checkpoint control has not been elucidated. In this report, we examined the role of JNK in LLnL-induced S phase checkpoint by overexpression of a dominant-negative mutant of JNK1 (JNK1-APF) in Calu-1 cells. Expression of high levels of JNK1-APF blocked the growth-inhibitory effects of LLnL and abrogated S phase arrest induced by LLnL. These results support the role of JNK in the activation of cell cycle checkpoint induced by LLnL.

Endemic tuberculosis among homeless men in New York City.

OBJECTIVES: The purpose of the study was to describe demographic and clinical characteristics of patients at the only long-term care facility for homeless men with tuberculosis in New York City, and to evaluate the outcome of a directly observed therapy program for these men. METHODS: The study population included residents at the "tuberculosis unit" for men in the New York City municipal shelter system. A cross-sectional survey described the characteristics of 76 men in the unit during November 1991. A retrospective cohort study evaluated 104 consecutive admissions to the facility from October 1, 1990, through March 30, 1991, and determined the outcome of directly observed therapy. RESULTS: Cross-sectional survey (n = 76). The median age was 43 years (range, 25 to 60 years); 67 patients (88%) had pulmonary tuberculosis. Among 58 isolates of Mycobacterium tuberculosis, eight were resistant to one drug (14%) and an additional nine were resistant to at least two drugs (16%). A history of previous treatment was associated with an odds ratio of 5.1 for having multiple drug-resistant tuberculosis (exact 95% confidence interval, 0.8 to 53.5). Retrospective cohort (n = 104). Excluding 21 men whose care was transferred to other agencies or institutions, 39 (47%) of 83 subjects completed or were still receiving treatment after 12 months and 44 (53%) of 83 subjects failed to complete the program. CONCLUSIONS: As expected, previous treatment for tuberculosis among homeless men is associated with an increased risk of having multiple-drug resistance. A directly observed therapy program successfully treated less than half of the enrolled subjects. Increased efforts are needed to control the spread of tuberculosis among homeless individuals.

Deletion of the adenoviral E1b-19kD gene enhances tumor cell killing of a replicating adenoviral vector.

Replicating adenoviral vectors are a promising new modality for cancer treatment and clinical trials with such vectors are ongoing. Targeting these vectors to cancer cells has been the focus of research. However, even if perfect targeting were to be achieved, a vector still must effectively kill cancer cells and spread throughout the bulk of the tumor. The adenoviral E1b-19kD protein is a potent inhibitor of apoptosis and may therefore compromise the therapeutic efficacy of an adenoviral vector. In this study we have investigated if an E1b-19kD gene deletion could improve the ability of a replicating adenoviral vector to spread through and kill cancer cells. In several lung cancer cell lines an E1b-19kD-deleted virus (Ad337) induced substantially more apoptosis than did a wild-type virus (Ad309), and tumor cell survival was significantly reduced in three of four cell lines. In addition, the apoptotic effects of cisplatin or paclitaxel were augmented by Ad337, but inhibited by wild-type virus. The number of infectious virus particles in the supernatant of infected cells was increased with Ad337 compared with wild-type virus, indicating enhanced early viral release. Ad337, in contrast to Ad309, induced significantly larger plaques after infection of A549 cells. This well-described large plaque phenotype of an E1b-19kD mutant virus is likely the result of early viral release and enhanced cell-to-cell viral spread. Loss of E1b-19kD function caused only minor cell line-specific increase or decrease in viral yield. We conclude that deletion of the E1b-19kD gene may enhance the tumoricidal effects of a replicating adenoviral vector.