Genetic variability of T cell responses in hypersensitivity pneumonitis identified using the BXD genetic reference panel.

Hypersensitivity pneumonitis (HP) is an interstitial lung disease that may progress to fibrosis and significant risk of death. HP develops following repeated exposures to inhaled environmental antigens; however, only a fraction of the exposed population develops the disease, suggesting that host genetics contribute to disease susceptibility. We used the BXD family of mice with the Saccharopolyspora rectivirgula (SR) model of HP to investigate the role of genetics in susceptibility to HP. The BXD family is derived from a B6 mother and a D2 father and has been used to map susceptibility loci to numerous diseases. B6, D2, and BXD progeny strains were exposed to SR for 3 wk, and the development of HP was monitored. The B6 and D2 strains developed alveolitis; however, the cellular composition was neutrophilic in the D2 strain and more lymphocytic in the B6 strain. Hematoxylin-eosin staining of lung sections revealed lymphoid aggregates in B6 lungs, whereas D2 lungs exhibited a neutrophilic infiltration. Twenty-eight BXD strains of mice were tested, and the results reveal significant heritable variation for numbers of CD4+ or CD8+ T cells in the air spaces. There was significant genetic variability for lymphoid aggregates and alveolar wall thickening. We mapped a significant quantitative trait locus (QTL) on chromosome 18 for CD8+CD69+ T cells that includes cadherin 2 (Cdh2), an excellent candidate gene associated with epithelial-mesenchymal transition, which is upregulated in lungs of strains with HP. These results demonstrate that the BXD family is a valuable and translationally relevant model to identify genes contributing to HP and to devise early and effective interventions.

Role of IL-17A and neutrophils in fibrosis in experimental hypersensitivity pneumonitis.

BACKGROUND: Chronic hypersensitivity pneumonitis is characterized by pulmonary inflammation and fibrosis in response to repeated inhalation of mainly organic antigens. It is recognized that IL-17A is crucial for the development of pulmonary inflammation in murine models of experimental hypersensitivity pneumonitis, but its role in the development of pulmonary fibrosis has not been determined. Furthermore, the main cell type(s) that produce IL-17A in experimental hypersensitivity pneumonitis have not yet been identified. OBJECTIVE: Our objectives were to test the hypothesis that IL-17A plays a central role in the development of pulmonary fibrosis in experimental hypersensitivity pneumonitis and to determine the main inflammatory cell type(s) responsible for IL-17A production. METHODS: We used a mouse model of experimental hypersensitivity pneumonitis in which IL-17A was inhibited or neutrophils were depleted. We also used IL-17RA-deficient and RAG-2-deficient mice. Lung IL-17A-producing cells were identified by fluorescence-activated cell sorting of myeloid versus lymphoid cell populations, intracellular IL-17A staining, flow cytometry, and quantitative reverse transcription PCR for IL-17A mRNA. RESULTS: We found that the development of pulmonary fibrosis depended on IL-17A and was significantly attenuated by neutrophil depletion. Neutrophils and monocytes/macrophages were the main cell types that expressed IL-17A in our model. CONCLUSIONS: We have identified the central roles of IL-17A and neutrophils in the pathogenesis of fibrosis in experimental hypersensitivity pneumonitis. We have also established that nonlymphocytic innate immune cells, specifically neutrophils and monocytes/macrophages, rather than TH17 lymphocytes, are the predominant source of IL-17A in experimental hypersensitivity pneumonitis.

Farmer's lung in a case after bullectomy.

We present a case of farmer's lung (FL) with the primary presenting feature of a large bulla in the lung. A 70-year-old nonsmoking woman with dyspnea on exercise was referred for surgical resection of a large bulla in the lung. The postoperative evaluation of the lung tissue revealed a follicular lymphocytic alveolitis and loosely formed granulomas suspicious for hypersensitivity pneumonitis (HP). The patient had worked in farming since her youth. Dyspnea on exercise was the only symptom, but it was related to the large bulla. No other radiologic features of HP were shown in a high-resolution CT of the lung. Specific IgG antibodies against typical antigens of FL were detected, bronchoalveolar lavage demonstrated no lymphocytic alveolitis but an inhalative challenge with own hay was positive. A diagnosis of chronic FL was made. Despite lung emphysema being a possible reaction in FL, giant bullae as primary and single manifestation of this disease have not been reported before.

Protein kinase D1 is essential for the proinflammatory response induced by hypersensitivity pneumonitis-causing thermophilic actinomycetes Saccharopolyspora rectivirgula.

Hypersensitivity pneumonitis is an interstitial lung disease that results from repeated pulmonary exposure to various organic Ags, including Saccharopolyspora rectivirgula, the causative agent of farmer's lung disease. Although the contributions of proinflammatory mediators to the disease pathogenesis are relatively well documented, the mechanism(s) involved in the initiation of proinflammatory responses against the causative microorganisms and the contribution of signaling molecules involved in the host immune defense have not been fully elucidated. In the current study, we found that S. rectivirgula induces the activation of protein kinase D (PKD)1 in lung cells in vitro and in vivo. Activation of PKD1 by S. rectivirgula was dependent on MyD88. Inhibition of PKD by pharmacological PKD inhibitor Gö6976 and silencing of PKD1 expression by small interfering RNA revealed that PKD1 is indispensable for S. rectivirgula-mediated activation of MAPKs and NF-kappaB and the expression of various proinflammatory cytokines and chemokines. In addition, compared with controls, mice pretreated with Gö6976 showed significantly suppressed alveolitis and neutrophil influx in bronchial alveolar lavage fluid and interstitial lung tissue, as well as substantially decreased myeloperoxidase activity in the lung after pulmonary exposure to S. rectivirgula. These results demonstrate that PKD1 is essential for S. rectivirgula-mediated proinflammatory immune responses and neutrophil influx in the lung. Our findings also imply the possibility that PKD1 is one of the critical factors that play a regulatory role in the development of hypersensitivity pneumonitis caused by microbial Ags and that inhibition of PKD1 activation could be an effective way to control microbial Ag-induced hypersensitivity pneumonitis.

Th17-polarized immune response in a murine model of hypersensitivity pneumonitis and lung fibrosis.

Hypersensitivity pneumonitis is an environmental lung disease characterized by a diffuse mononuclear cell infiltrate in the lung that can progress to pulmonary fibrosis with chronic exposure to an inhaled Ag. Using a well-established murine model of hypersensitivity pneumonitis, we repeatedly exposed C57BL/6 mice to Saccharopolyspora rectivirgula to investigate whether T cells are required for lung fibrosis. In the absence of alphabeta T cells, TCRbeta(-/-) mice exposed to S. rectivirgula for 4 wk had markedly decreased mononuclear infiltrates and collagen deposition in the lung compared with wild-type C57BL/6 mice. In contrast to CD8(+) T cells, adoptive transfer of CD4(+) T cells reconstituted the S. rectivirgula-induced inflammatory and fibrotic response, suggesting that the CD4(+) T cell represents the critical alphabeta T cell subset. Cytokine analysis of lung homogenates at various time points after S. rectivirgula exposure failed to identify a predominant Th1 or Th2 phenotype. Conversely, IL-17 was found in the lung at increasing concentrations with continued exposure to S. rectivirgula. Intracellular cytokine staining revealed that 14% of CD4(+) T cells from the lung of mice treated with S. rectivirgula expressed IL-17A. In the absence of IL-17 receptor signaling, Il17ra(-/-) mice had significantly decreased lung inflammation and fibrosis compared with wild-type C57BL/6 mice. These data are the first to demonstrate an important role for Th17-polarized CD4(+) T lymphocytes in the immune response directed against S. rectivirgula in this murine model of hypersensitivity pneumonitis and pulmonary fibrosis.

Toll-like receptor 6 drives interleukin-17A expression during experimental hypersensitivity pneumonitis.

Hypersensitivity pneumonitis (HP) is a T-cell-driven disease that is histologically characterized by diffuse mononuclear cell infiltrates and loosely formed granulomas in the lungs. We have previously reported that interleukin-17A (IL-17A) contributes to the development of experimental HP, and that the pattern recognition receptor Toll-like receptor 6 (TLR6) might be a factor in the initiation of this response. Using a well-established murine model of Saccharopolyspora rectivirgula-induced HP, we investigated the role of TLR6 in the immunopathogenesis of this disease. In the absence of TLR6 signalling, mice that received multiple challenges with S. rectivirgula-antigen (SR-Ag) had significantly less lung inflammation compared with C57BL/6 mice (wild-type; WT) similarly challenged with SR-Ag. Flow cytometric analysis of whole lung samples from SR-Ag-challenged mice showed that TLR6(-/-) mice had a decreased CD4(+) : CD8(+) T-cell ratio compared with WT mice. Cytokine analysis at various days after the final SR-Ag challenge revealed that whole lungs from TLR6(-/-) mice contained significantly less IL-17A than lungs from WT mice with HP. The IL-17A-driving cytokines IL-21 and IL-23 were also expressed at lower levels in SR-Ag-challenged TLR6(-/-) mice, when compared with SR-Ag-challenged WT mice. Other pro-inflammatory cytokines, namely interferon-gamma and RANTES, were also found to be regulated by TLR6 signalling. Anti-TLR6 neutralizing antibody treatment of dispersed lung cells significantly impaired SR-Ag-induced IL-17A and IL-6 generation. Together, these results indicate that TLR6 plays a pivotal role in the development and severity of HP via its role in IL-17A production.

Inflammatory response and dynamics of lung T cell subsets in Th1, Th2 biased and Th2 deficient mice during the development of hypersensitivity pneumonitis.

It is considered that hypersensitivity pneumonitis (HP) occurs with a Th1 cell dominance; however, the role of Th1/Th2 balance is still unclear. C57BL/6 (Th1-biased), BALB/c wt (Th2-biased) and BALB/c Stat6-/- (Th2 deficient) mice were treated with Saccharopolyspora rectivirgula (SR) or saline during 3 weeks, and sacrificed 1 and 4 days (early and late response) after the last administration. Lung isolated T cell subpopulations were analyzed and lung damage extent was quantified. C57BL/6 wt mice exhibited a significant increase in the extent of lung damage when sacrificed at 4 days compared with those sacrificed 1 day after the last SR administration. In contrast, BALB/c wt mice showed a progressive decrease in the extent of lung damage. A significant increase of NKT CD4+ subset was found in C57BL/6 mice while NKT DN cells were increased in BALBc wt mice. Also, NK and gammadelta T cells were increased in BALB/c mice at 1 and 4 days. Stat6-/- mice behave similar to the C57BL/6 mice, showing a progressive increase in the extent of lung damage. A significant increase in the levels of Th1 and Th2 cytokines was observed in bronchoalveolar lavage from the SR-treated mice. These results confirm a predominant role of the Th1 response in HP and suggest that the control of inflammation by Th2 biased mice may be related with the increase of NKT DN cells and regulatory NK and gammadelta T cells.

Interleukin-17-mediated immunopathogenesis in experimental hypersensitivity pneumonitis.

RATIONALE: T cells play a critical role in the development of Saccharopolyspora rectivirgula-induced hypersensitivity pneumonitis (HP) but little is known about the role of IL-17A in this disease. OBJECTIVES: We examined the role of IL-17A in a murine model of S. rectivirgula antigen (SR-Ag)-induced HP. METHODS: Experimental HP was induced by oropharyngeal instillation of SR-Ag in wild-type and IL-17 gene-deficient mice. MEASUREMENTS AND MAIN RESULTS: SR-Ag-induced murine HP was characterized by increased transcript levels of IFN-gamma and IL-12p35 compared with saline-treated control mice. Furthermore, mice with HP showed increased IL-17 in lung homogenates, bronchoalveolar lavage fluid, and ex-vivo lung cultures compared with control mice. Flow cytometric analysis of SR-Ag-challenged lungs revealed increased Th17 and CD11c(+) cells. The role of IL-17 in SR-induced HP was examined in IL-17 deficient (IL17(-/-)) and in wild-type (IL-17(+/+)) mice immunodepleted of IL-17. Histological examination of IL17(-/-) mice challenged with SR-Ag revealed reduced inflammatory cell infiltration, decreased CD11c(+) cells, and reduced levels of inflammatory mediators such as IL-12p70, CCL3, and CXCL9 compared with similarly treated IL17(+/+) mice. Anti-IL-17 antibody treatment of IL-17(+/+) mice with HP resulted in reduced inflammation and a lower percentage of CD11c(+) cells compared with IgG-treated IL-17(+/+) mice with HP. CONCLUSIONS: SR-Ag-induced IL-17 plays a pivotal role in the immunopathology of HP and targeting IL-17 is an attractive therapeutic option for this disease.

Mature CD11c(+) cells are enhanced in hypersensitivity pneumonitis.

The present study verified the hypothesis that enhanced maturation of antigen-presenting CD11c(+) cells could explain the viral-induced exacerbated immune response to Saccharopolyspora rectivirgula (SR), the main antigen responsible for farmer's lung, a classic form of hypersensitivity pneumonitis (HP). Four groups of mice were studied: group 1 received intranasal instillations of saline; group 2 received instillations of SR for 12 weeks; group 3 received instillations of saline and a single infection with Sendai virus on week 3; and group 4 received instillations of SR for 12 weeks with a single administration of Sendai virus on week 3. On week 13, mice were sacrificed and bronchoalveolar lavage was performed. Lungs were harvested, digested with enzymes, and CD11c(+) cells were analysed in flow cytometry with anti-CD11c, anti-CD86 and anti-major histocompatibility complex class II markers. Immunofluorescence studies were also performed with the same cell surface markers. Both flow cytometry and immunofluorescence results demonstrate that mature CD11c(+) cells are significantly enhanced in SR-challenged mice simultaneously infected with Sendai virus, compared with other groups. These CD11c(+) cells persist in the lung for 9 weeks after the virus infection. Maturation of CD11c(+) cells could explain, at least in part, the virus-induced increased immune response to SR antigens in this model of HP, but mechanisms have still to be elucidated.

Interferon-gamma is necessary for the expression of hypersensitivity pneumonitis.

Farmers lung disease is a common form of hypersensitivity pneumonitis (HP) and is characterized by inflammation and granuloma formation in the lung. Interferon-gamma is important for the expression of granulomatous diseases caused by infectious agents; however, the role this mediator in regulating expression of the granulomatous response to inhaled antigen is not known. To evaluate this, we compared the response to inhaled antigen of mice that do not express the gene coding for interferon-gamma (GKO) with that of their normal littermates (WT). GKO and WT mice on a BALB/c background were exposed to 150 microg of the thermophilic bacteria Saccharopolyspora rectivirgula or saline alone, for three consecutive days a week, for 3 wk. After exposure to antigen, WT mice developed a marked granulomatous inflammation associated with an increase in lung weight and numbers of cells in bronchoalveolar lavage fluid (BAL). Although GKO mice also exhibited an increase in lung weight and numbers of cells in BAL fluid, they developed minimal inflammation and no granulomas after a similar exposure to antigen. To further evaluate if the lack of a response to antigen in GKO mice was due to lack of IFN-gamma, we replaced this mediator via intraperitoneal injections. When given replacement IFN-gamma, the GKO mice developed granulomatous inflammation in the lung. These studies show that IFN-gamma is essential for the expression of hypersensitivity pneumonitis.

Assessment of four serological techniques in the immunological diagnosis of farmers' lung disease.

Farmers' lung disease (FLD) is a pulmonary disease that results from repeated inhalation of antigens from mouldy hay or straw. The objective of this prospective study was to assess the reliability of four serological techniques in FLD diagnosis. Sera from 15 consecutive patients with FLD, 15 healthy control farmers and 30 urban controls were analysed using four serological techniques [electrosyneresis (ES), Ouchterlony double diffusion (DD), ELISA and Western blot (WB)] with four antigens (Absidia corymbifera, Eurotium amstelodami, Wallemia sebi and Saccharopolyspora rectivirgula). In the authors' region, ES on cellulose acetate with A. corymbifera antigen was the most relevant diagnostic tool for discriminating FLD patients from healthy exposed farmers (sensitivity 87 %, specificity 100 %). DD tests were in accordance with ES, but their discriminatory power was lower. No threshold indicating both good sensitivity and specificity could be established with ELISA. WB analysis failed to identify specific bands for FLD. This study demonstrates the efficacy of determining precipitin levels with an appropriate technique, using a panel of antigens consistent with the specific exposure of a given area.

[Exposure to organic dust and microorganisms as a factor affecting respiratory function of workers of purebred horse farms]. / Narazenie na pyl organiczny i drobnoustroje jako czynnik wplywajacy na stan ukladu oddechowego pracowników stadniny koni.

In two farms of purebred horses, microbiological studies of the air and medical examination of the workers were performed. The concentration of microorganisms in the air were within the range 29.2-336.0 cfu x 10(3)/m3. The respirable fraction in most cases was between 30-60% of the total count. The levels of dust and endotoxin were low except for one sampling point where the concentration of endotoxin was as high as 3.44 g/m3. As many as 16 workers out of the total of 31 examined reported occurrence of work-related symptoms. However, the results of physical examination and of lung function tests were within normal range. A high proportion of workers showed a positive skin response to Saccharopolyspora rectivirgula (51.6%) and the presence of precipitins to Acinetobacter calcoaceticus (32.3%). No significant relationship could be found between the presence of symptoms and positive allergological reactions. Total medical results indicate the probability of the occurrence of Organic Dust Toxic Syndrome in high proportion of the workers.

Immunoreactive proteins of Saccharopolyspora rectivirgula for farmer's lung serodiagnosis.

PURPOSE: Saccharopolyspora rectivirgula is the principal cause of farmer's lung disease (FLD). Serodiagnosis is based on immunoprecipitation techniques or enzyme immunoassays with homemade crude antigens and is not standardized. We aimed to produce specific recombinant antigens for the development of a standardized ELISA. EXPERIMENTAL DESIGN: We recruited 41 patients and 43 healthy exposed controls from five university hospital pneumology departments in France and Switzerland. S. rectivirgula proteins were extracted, separated by 2D electrophoresis, and subjected to Western blotting, with sera from FLD patients or controls. FLD-specific proteins were identified by MS and were produced as recombinant antigens. The diagnostic performance of ELISA tests using the recombinant antigens was assessed with all the sera from FLD patients and controls. RESULTS: We identified 25 FLD-specific proteins, some of which play important roles in transport, nutrition, or virulence. We produced 17 of these proteins as recombinant antigens and assessed their suitability for inclusion in the ELISA test. A combination of three of these proteins (SR1FA, SR17, and SR22) proved remarkably effective at discriminating between patients and controls, with a sensitivity of 83% and a specificity of 77%. CONCLUSIONS AND CLINICAL RELEVANCE: The recombinant antigens produced in this study constitute a major step toward the improvement of diagnostic performance and the standardization of FLD serodiagnosis.

IFN-gamma production by innate immune cells is sufficient for development of hypersensitivity pneumonitis.

Hypersensitivity pneumonitis (HP) is an interstitial lung disease that develops following repeated exposure to inhaled particulate antigens. The disease is characterized by lymphocytic alveolitis, granuloma formation and fibrosis. IFN-gamma is required for the formation of granulomas in HP, and we therefore focused on identifying the cellular sources of IFN-gamma during the disease. Using the Saccharopolyspora rectivirgula (SR) animal model of HP, we demonstrated that the majority of IFN-gamma(+) cells in the lung following SR exposure are neutrophils. Ab-mediated depletion of neutrophils in mice prior to exposure to SR resulted in a decrease in the level of IFN-gamma mRNA and protein compared to isotype Ab-treated mice, suggesting that neutrophils are an important source of IFN-gamma during HP. To determine the contribution of T and non-T cell sources of IFN-gamma to granuloma formation, we performed adoptive transfer studies. RAG-1(-/-) mice reconstituted with spleen cells from IFN-gamma(-/-) mice developed granulomas similarly to RAG-1(-/-) mice reconstituted with normal spleen cells. Therefore innate immune cell IFN-gamma production in the absence of T cell IFN-gamma production is sufficient for granuloma formation. These results provide new insight into the pathogenesis of HP and demonstrate the important contribution of innate immune cells to the disease process.

Tumor necrosis factor plays an essential role in determining hypersensitivity pneumonitis in a mouse model.

We examined the importance of the cytokine tumor necrosis factor-alpha (TNF-alpha) in a mouse model of hypersensitivity pneumonitis (HP). Mice of the C57BL/6 strain were instilled intranasally 3 days/wk for 3 wk with 150 micrograms of the actinomycete Faenia rectivirgula (Micropolyspora faeni) to induce HP as a model of farmer's lung. This experimental model was associated with a progressive inflammation in the lungs of challenged mice, seen histologically as cellular infiltrates of large quantities of macrophages and lymphocytes and some neutrophils. The disease in challenged mice treated with a control rabbit serum was also associated with a substantial release of tumor TNF-alpha (up to 80 U/ml of TNF-alpha in the bronchoalveolar lavage [BAL] at 3 wk after beginning of treatment) and interleukin-1, which peaked at 1 wk (approximately 300 U/ml) and diminished thereafter. A very large increase in BAL cell number (11-fold increase versus saline controls) and an enhanced release potential for TNF-alpha by alveolar macrophages was also seen. Lung fibrosis was also evident in challenged animals, as demonstrated by a 2-fold increase in hydroxyproline levels. Infusion of challenged mice with a rabbit polyclonal antibody against TNF-alpha (2 mg/wk) completely abrogated the disease, as mice so treated had normal lung histology. Anti-TNF-alpha blocked cellular recruitment in the lungs (only a 2-fold increase at week 3); it also completely abolished TNF-alpha secretion in the BAL and drastically reduced interleukin-1 levels in this fluid. Anti-TNF-alpha also abolished lung index increases and lung fibrosis, with both parameters similar to that of saline-instilled mice.(ABSTRACT TRUNCATED AT 250 WORDS)

Viral infection enhances the response to Saccharopolyspora rectivirgula in mice prechallenged with this farmer's lung antigen.

Sendai viral infection enhances mice lung response to Saccharopolyspora rectivirgula (SR). The mechanisms of this viral enhancement remain unclear. The present study was done to verify if the viral infection was required and if the presence of the viral infection needed to be given simultaneously with the SR antigen for the enhanced response to occur. In a first experiment groups of C57BL/6 mice were instilled concomitantly with SR and live or inactivated Sendai virus. In a second experiment the viral infection in the appropriate group preceded the SR challenges by 4 weeks. As reported previously SR induced a cellular inflammatory response. This effect of SR was enhanced by the viral infection but not by inactivated virus particles. Total lavage cells 3 weeks after the virus inoculation in the appropriate groups were: saline = 69 +/- 15 x 10(3); SR = 678 +/- 104 x 10(3); Sendai = 277 +/- 61 x 10(3); inactivated Sendai = 73 +/- 23 x 10(3); SR + Sendai = 1232 +/- 232 x 10(3); SR + inactivated Sendai = 515 +/- 54 x 10(3). In the second experiment, where the infection preceded the SR challenge, no enhancement was observed. We conclude that Sendai virus enhances mice lung response to SR by an infectious process when both SR and the virus are present simultaneously.

Is IL12 necessary in experimental hypersensitivity pneumonitis?

Inhalation of Saccharopolyspora rectivirgula (SR) can cause the disease Farmer's Lung, a classic example of hypersensitivity pneumonitis. Th1, but not Th2, cell lines can adoptively transfer experimental hypersensitivity pneumonitis (EHP). Substantial amounts of IL12 appear in bronchoalveolar lavage fluid (BALF) after a single intratracheal (IT) injection of SR, and SR-induced IL12 secretion by both a macrophage cell line and alveolar macrophages. We tested the hypothesis that IL12 is essential for the development of EHP by addition of anti-IL12 to cultured cells, and adoptive transfer of EHP in IL12p40-/- animals. We transferred SR cultured spleen and lung associated lymph node cells from SR sensitized mice (both IL12p40-/- and wild type), to naïve recipients (both wild type and IL12p40-/-). The addition of anti-IL12 to cultures of sensitized cells could not ablate the ability of these cells to transfer EHP. Cultured cells from IL12p40-/- animals were fully capable of transferring EHP. In contrast, IL12p40-/- recipients of both wild type and IL12p40-/--cultured cells were less able to express EHP (lung histology and BALF characteristics) than wild type mice, and had more eosinophils in both lung tissue and BALF. We conclude that IL12 is not necessary for development of cells able to adoptively transfer EHP, but that it is required for full expression of EHP in recipient animals.

Monoclonal antibodies against farmer's lung antigens having specific binding to IgG antibodies.

Hypersensitivity pneumonitis resulting from environmental exposure to Saccharopolyspora rectivirgula (Micropolyspora faeni) among farmers has been well recognized. The diagnosis of the disease depends on demonstration of circulating antibodies against S. rectivirgula. However, dependable pure antigens are not available for serodiagnosis. In the present study we have employed hybridoma technology to obtain monoclonal antibodies against S. rectivirgula antigens. These monoclonal antibodies were employed to purify antigens through affinity chromatography. When tested in ELISA, high levels of antibodies were demonstrated against these antigens in farmer's lung patient sera compared to exposed but asymptomatic individuals from the same household. In Western blots patient sera reacted with components of crude antigens with molecular masses of 28, 35, 60, 65 and 68 kD and 4 components above 100 kD, while the monoclonal antibodies reacted only with the 60-kD protein. These purified antigens can be used as reliable reagents in the specific diagnosis of farmer's lung disease.

Thermophilic actinomycetes in cane sugar mills: an aeromicrobiologic and seroepidemiologic study.

Aerial prevalence of clinically important thermophilic actinomycetes and occurrence of precipitating antibodies against them in sera of 153 exposed workers have been reported. The study was carried out in two cane sugar mills namely, the Upper Doab Sugar Mills and the Ramala Sugar Mills, located in north-west India. In both the sugar mills, T. sacchari was the predominant species, it accounted for 55.1% and 50.3% of the total population of thermophilic actinomycetes, followed by T. vulgaris (19.7% and 23.7%), T. thalpophilus (21.1% and 17.1%), Saccharomonospora viridis (3.4% and 5.0%) and Saccharopolyspora rectivirgula (Faenia rectivirgula) (0.7% and 3.9%), respectively. Precipitating antibodies against thermophilic actinomycetes were demonstrable in 34 (22.2%) workers; T. sacchari alone accounted for 20 of the positive precipitin reactions, followed by S. rectivirgula in 10. The mean absorbance values for IgG antibody activity against T. sacchari as well as S. rectivirgula were found to be elevated significantly in the symptomatic workers than in the asymptomatic workers (p < 0.05) or unexposed controls (p < 0.001). However, the difference in IgG antibody activity was insignificant between precipitin-positive symptomatic workers and precipitin-positive asymptomatic workers. The results indicate that clinically important thermophilic actinomycetes are widely prevalent in cane sugar mills, and T. sacchari and S. rectivirgula are the major species involved in the sensitization of the bagasse workers in India.

Transforming growth factor-beta is generated in the course of hypersensitivity pneumonitis: contribution to collagen synthesis.

Mice of the C57BL/6 strain were instilled with optimal doses (150 micrograms/day for 3 days/wk) of the thermophilic actinomycete Faeni rectivirgula (also known as Saccharopolyspora rectivirgula or Micropolyspora faeni) to induce a hypersensitivity pneumonitis inflammation that mimics the human disease affecting certain occupational groups. This mouse model was characterized by a very significant alveolitis (3-fold increase in bronchoalveolar lavage [BAL] cell number at 48 h and a 10-fold increase at 3 wk). Also, total lung transforming growth factor (TGF-beta) was shown to be elevated in treated mice as early as 1 wk after the first instillation and increased gradually to 2.5 micrograms/lung at 3 wk (approximately 0.3 microgram/lung in saline-instilled controls). Intranasal instillation with F. rectivirgula was also associated with very significant increases in lung fibroblast collagen synthesis, starting at 2 wk. BAL macrophages from mice instilled with F. rectivirgula were found to release significantly more TGF-beta upon in vitro stimulation with zymosan beads than did BAL macrophages from saline-instilled mice. Finally, we show that supernatants from activated BAL macrophages of mice given F. rectivirgula increased quite significantly collagen synthesis in normal mouse lung fibroblasts. This increase could be abrogated by treating conditioned medium with a rabbit antibody against TGF-beta. Collectively, these data suggest that TGF-beta is generated in the course of experimental mouse hypersensitivity pneumonitis and contributes significantly to collagen synthesis.