IL-15-deficient mice develop enhanced allergic responses to airway allergen exposure.

BACKGROUND: Interleukin-15 is a pleiotropic cytokine that is critical for the development and survival of multiple haematopoietic lineages. Mice lacking IL-15 have selective defects in populations of several pro-allergic immune cells including natural killer (NK) cells, NKT cells, and memory CD8+ T cells. We therefore hypothesized that IL-15-/- mice will have reduced inflammatory responses during the development of allergic airway disease (AAD). OBJECTIVE: To determine whether IL-15-/- mice have attenuated allergic responses in a mouse model of AAD. METHODS: C57BL/6 wild-type (WT) and IL-15-/- mice were sensitized and challenged with ovalbumin (OVA), and the development of AAD was ascertained by examining changes in airway inflammatory responses, Th2 responses, and lung histopathology. RESULTS: Here, we report that IL-15-/- mice developed enhanced allergic responses in an OVA-induced model of AAD. In the absence of IL-15, OVA-challenged mice exhibited enhanced bronchial eosinophilic inflammation, elevated IL-13 production, and severe lung histopathology in comparison with WT mice. In addition, increased numbers of CD4+ T and B cells in the spleens and bronchoalveolar lavage (BAL) were also observed. Examination of OVA-challenged IL-15Rα-/- animals revealed a similar phenotype resulting in enhanced airway eosinophilia compared to WT mice. Adoptive transfer of splenic CD8+ T cells from OVA-sensitized WT mice suppressed the enhancement of eosinophilia in IL-15-/- animals to levels observed in WT mice, but had no further effects. CONCLUSION AND CLINICAL RELEVANCE: These data demonstrate that mice with an endogenous IL-15 deficiency are susceptible to the development of severe, enhanced Th2-mediated AAD, which can be regulated by CD8+ T cells. Furthermore, the development of disease as well as allergen-specific Th2 responses occurs despite deficiencies in several IL-15-dependent cell types including NK, NKT, and γδ T cells, suggesting that these cells or their subsets are dispensable for the induction of AAD in IL-15-deficient mice.

Pro-inflammatory role of natural killer cells in the development of allergic airway disease.

BACKGROUND: Natural Killer (NK) cells have been implicated in the development of allergic airway inflammation. However, the in vivo role of NK cells has not been firmly established due to the lack of animal models with selective deficiencies in NK cells. OBJECTIVE: To determine the specific contribution of NK cells in a murine model of allergic airway disease (AAD). METHODS: The role of NK cells in AAD was studied using NK-deficient (NKD) mice, perforin(-/-) mice, and mice depleted of Ly49A/D/G(+) NK cell subsets in an ovalbumin-induced model of allergic airway disease (OVA-AAD). RESULTS: Induction of OVA-AAD in C57BL/6 wild-type (WT) mice resulted in the expansion of airway NK cells and the development of pronounced airway eosinophilia. In the absence of NK cells or specific subsets of NK cells, either in NKD mice, or after the depletion of Ly49A/D/G(+) NK cells, the development of OVA-AAD was significantly impaired as seen by decreased airway inflammation and eosinophilia, decreased secretion of the Th2 cytokines IL-4, IL-5 and IL-13 and diminished OVA-specific antibody production. Furthermore, while OVA-exposure induced a dramatic expansion of dendritic cells (DCs) in WT mice, their induction was significantly attenuated in NKD mice. Development of OVA-AAD in perforin(-/-) mice suggested that the proinflammatory role of NK cells is not dependent on perforin-mediated cytotoxicity. Lastly, induction of allergic disease by OVA-specific CD4 T cells from WT but not NK-depleted or NKD mice in RAG(-/-) recipients, demonstrates that NK cells are essential for T cell priming. CONCLUSIONS AND CLINICAL RELEVANCE: Our data demonstrate that conventional NK cells play an important and distinct role in the development of AAD. The presence of activated NK cells has been noted in patients with asthma. Understanding the mechanisms by which NK cells regulate allergic disease is therefore an important component of treatment approaches.

Regulatory B cells from hilar lymph nodes of tolerant mice in a murine model of allergic airway disease are CD5+, express TGF-ß, and co-localize with CD4+Foxp3+ T cells.

In a biphasic, ovalbumin (OVA)-induced murine asthma model where allergic airway disease is followed by resolution and the development of local inhalational tolerance (LIT), transforming growth factor (TGF)-ß-expressing CD5(+) B cells were selectively expanded locally in hilar lymph nodes (HLN) of LIT mice. LIT HLN CD5(+) B cells, but not LIT HLN CD5(-) B cells, induced expression of Foxp3 in CD4(+)CD25(-) T cells in vitro. These CD5(+) regulatory B cells (Breg) and CD4(+)Foxp3(+) T cells demonstrated similar increases in expression of chemokine receptors (CXCR4 and CXCR5) and co-localized in HLN B cell zones of LIT mice. The adoptive transfer of LIT HLN CD5(+) B cells, but not LIT HLN CD5(-) B cells, increased the number of CD4(+)Foxp3(+) T cells in the lung and inhibited airway eosinophilia in this OVA model. Thus, Breg in HLNs of LIT mice reside in a CD5(+) TGF-ß-producing subpopulation and co-localize with CD4(+)Foxp3(+) T cells.

Tolerance induced by chronic inhaled antigen in a murine asthma model is not mediated by endotoxin.

Ovalbumin (OVA)-sensitized wildtype (WT) and endotoxin-resistant (ER) mice developed similar degrees of airways eosinophilia and serum OVA-specific IgE levels after acute aerosolized OVA challenge. WT mice demonstrated methacholine hyperreactivity, whereas ER mice showed no change in responsiveness. With chronic aerosolized OVA challenge, both WT and ER mice developed local tolerance, with resolution of airway eosinophilia but persistence of anti-OVA IgE in serum. Thus, the development of local tolerance with chronic aerosol exposure to OVA is independent of any potential effects of endotoxin in the OVA aerosol solution.

Murine cytomegalovirus infection alters Th1/Th2 cytokine expression, decreases airway eosinophilia, and enhances mucus production in allergic airway disease.

Concomitant infection of murine CMV (MCMV), an opportunistic respiratory pathogen, altered Th1/Th2 cytokine expression, decreased bronchoalveolar lavage (BAL) fluid eosinophilia, and increased mucus production in a murine model of OVA-induced allergic airway disease. Although no change in the total number of leukocytes infiltrating the lung was observed between challenged and MCMV/challenged mice, the cellular profile differed dramatically. After 10 days of OVA-aerosol challenge, eosinophils comprised 64% of the total leukocyte population in BAL fluid from challenged mice compared with 11% in MCMV/challenged mice. Lymphocytes increased from 11% in challenged mice to 30% in MCMV/challenged mice, and this increase corresponded with an increase in the ratio of CD8(+) to CD4(+)TCRalphabeta lymphocytes. The decline in BAL fluid eosinophilia was associated with a change in local Th1/Th2 cytokine profiles. Enhanced levels of IL-4, IL-5, IL-10, and IL-13 were detected in lung tissue from challenged mice by RNase protection assays. In contrast, MCMV/challenged mice transiently expressed elevated levels of IFN-gamma and IL-10 mRNAs, as well as decreased levels of IL-4, IL-5, and IL-13 mRNAs. Elevated levels of IFN-gamma and reduced levels of IL-5 were also demonstrated in BAL fluid from MCMV/challenged mice. Histological evaluation of lung sections revealed extensive mucus plugging and epithelial cell hypertrophy/hyperplasia only in MCMV/challenged mice. Interestingly, the development of airway hyperresponsiveness was observed in challenged mice, not MCMV/challenged mice. Thus, MCMV infection can modulate allergic airway inflammation, and these findings suggest that enhanced mucus production may occur independently of BAL fluid eosinophilia.

Early detection of oleic acid-induced lung injury in rats using (111)In-labeled anti-rat intercellular adhesion molecule-1.

UNLABELLED: Previous study of the bleomycin-induced lung injury model suggested that (111)In-labeled antirat intercellular adhesion molecule-1 (aICAM-1) might be a useful acute respiratory distress syndrome (ARDS) diagnostic agent. We further investigated the ability of (111)In-aICAM-1 to detect inflammation in another ARDS lung injury model. METHODS: (111)In-labeled rat polymorphonuclear leukocytes (PMNs), (111)In-aICAM-1, (111)In-labeled normal mouse IgG (nmIgG), and (111)In-labeled rat serum albumin (RSA) were injected into rats 18-24 h before kill. Biodistributions, scintigraphic images, and lung ICAM-1 upregulation were obtained in uninjured rats and in rats after injury with oleic acid. RESULTS: (111)In-RSA and (111)In-nmIgG localized in inflamed lung at 5 min postinjury (PI). (111)In-PMN uptake increased significantly only at 24 h PI. (111)In-aICAM-1 localization increased significantly (30%-60%) at 1 h PI and remained elevated up to 24 h PI. Lung/blood ratios (L/B) at 1 and 4 h PI were very low (<0.6) for (111)In-nmIgG and (111)In-PMN rats; however, for (111)In-aICAM-1 rats, they were >1 and 25%-60% higher than those for the control samples. A low L/B suggests poor inflammation detection on the images. Images and region-of-interest analysis confirmed that only (111)In-aICAM-1 could distinguish inflamed lungs at 4 h PI. ICAM-1 was upregulated at 4 and 24 h PI. CONCLUSION: In this model, (111)In-aICAM-1 detected lung inflammation very early in the course of the disease. These results support the suggestion that (111)In-aICAM-1 could be a very early, highly specific ARDS diagnostic agent and may be useful to detect a wide range of inflammations.

Functional status and survival following pulmonary rehabilitation.

BACKGROUND: Functional exercise capacity has been shown to be a strong predictor of survival following pulmonary rehabilitation. This study evaluated whether questionnaire-rated functional status is also predictive of survival. PATIENTS AND METHODS: Following pulmonary rehabilitation, patients with advanced chronic lung disease were evaluated for survival, 6-min walk distance, and questionnaire-rated functional status. The latter was measured using the pulmonary functional status scale, which has subscores of functional activities, psychological status, and dyspnea. Information on survival was available on 149 patients. RESULTS: The mean age was 69 years, and 45% of patients were male. Eighty-nine percent had a diagnosis of COPD, and their FEV(1) was 37+/-18% of predicted. Ninety-one (61%) were married. The 3-year survival for the group was 85%. Age, gender, body mass index, and primary diagnosis were not related to survival. Variables strongly associated with increased survival following pulmonary rehabilitation included a higher postrehabilitation Functional Activities score, a longer postrehabilitation 6-min walk distance, and being married (vs widowed, single, or divorced). Disease severity variables associated with survival included an initial referral to outpatient pulmonary rehabilitation, no supplemental oxygen requirement, and a higher percent-predicted FEV(1). CONCLUSION: Indicators of functional status are strong predictors of survival in patients with advanced lung disease.

Neutrophil beta2-integrin upregulation is blocked by a p38 MAP kinase inhibitor.

Tumor necrosis factor-alpha is known to upregulate the expression of surface adhesion molecules on polymorphonuclear leukocytes (PMNs). The purpose of this investigation was to study possible intracellular signaling pathways responsible for the upregulation of beta2 integrins on normal human PMNs induced by TNF. We report that treatment with TNF (10 ng/ml) for 30 min resulted in a significant increase in CD18 and MAC-1 surface expression (P < 0.001). In addition, pretreatment with 15 microM SB203580, a p38 MAP kinase inhibitor, for 10 min significantly inhibited TNF upregulation of CD18 and MAC-1 (P < 0.0001). Pretreatment with either 15 microM PD 98059, a p42/44 MAP kinase inhibitor, or 5 microM GO 6850, a protein kinase C inhibitor, had no significant inhibitory effect. These data suggest that the TNF-induced upregulation of beta2 integrins is mediated specifically through the p38 MAP kinase pathway and not through the p42/44 MAP kinase or protein kinase C pathways.

Proinflammatory roles of T-cell receptor (TCR)gammadelta and TCRalphabeta lymphocytes in a murine model of asthma.

The role of lymphocytes bearing alphabeta or gammadelta T-cell receptors (TCRs) was assessed during the acute allergic response in a mouse model of asthma. The inflammatory immune response to ovalbumin (OVA) was characterized in wild-type C57BL/6J mice and congenic TCRbeta(-/-) and TCRdelta(-/-) mice by evaluation of airway eosinophilia, histopathology, serum immunoglobulin (Ig)E levels, and in vivo airway responsiveness to methacholine. OVA-challenged wild-type mice demonstrated marked pulmonary inflammation, evidenced by airway eosinophilia (68 +/- 7 x 10(4) cells), peribronchial lympho-plasmocytic infiltration, and elevated serum IgE (4.9 +/- 0.6 microg/ml). These responses were markedly attenuated in TCRdelta(-/-) animals (5.0 +/- 1.0 x 10(4) eosinophils and 1.6 +/- 0. 3 microg/ml IgE) and were completely absent in TCRbeta(-/-) mice (< 1 x 10(3) eosinophils and 0.38 +/- 0.21 microg/ml IgE). Similar results were observed in mice treated with anti-TCRgammadelta or anti-TCRalphabeta monoclonal antibodies. Airway responsiveness to aerosolized methacholine was also reduced in challenged TCRdelta(-/-) animals relative to challenged wild-type mice. These results demonstrate that acute allergic airway responses are dependent upon intact TCRalphabeta and TCRgammadelta lymphocyte function and that TCRgammadelta cells promote acute airway sensitization.

Long-term benefits of short-stay inpatient pulmonary rehabilitation in severe chronic obstructive pulmonary disease.

The beneficial effects of pulmonary rehabilitation programmes on the overall quality of life in patients with chronic obstructive pulmonary disease (COPD) has been well documented. However, there has been a paucity of studies demonstrating the long-term benefits of short-stay inpatient pulmonary rehabilitation (SSIPR) programmes in patients with severe COPD (forced expiratory volume in one second (FEV1) < 40% of predicted). The authors have previously reported that their multidisciplinary SSIPR programme improved outcome measurements immediately post-rehabilitation in 38 patients with severe COPD. The purpose of this study was to evaluate the long-term (1-yr follow-up) benefits of SSIPR in these patients. The outcome measurements used were: timed 12-min walking distance, Borg dyspnoea scale, annual days of acute care hospitalization, and Pulmonary Functional Status Scale. All outcome measurements were significantly improved at 1 yr post-SSIPR as compared to pre-SSIPR values. The 12-min walking distance was significantly improved in patients 1 yr post-SSIPR (251 m) as compared to either pre-SSIPR (133 m, p < 0.0001) or immediately post-SSIPR (224 m, p < 0.01). The number of annual days of acute care hospitalization was reduced from 15.4 pre-SSIPR to 3.8 (p < 0.0001) 1 yr post-SSIPR. The Borg dyspnoea scale measurement showed improvement, both at rest and after 12 min walking at 1 yr post-SSIPR. Also, the Pulmonary Functional Status Scale analysis showed significant (p < 0.001) sustained improvement at 1 yr post-SSIPR as compared to pre-SSIPR. In conclusion, it has been demonstrated that long-term sustained outcome benefits can be achieved from a comprehensive short-stay inpatient pulmonary rehabilitation programme for patients with severe chronic obstructive pulmonary disease.

Shifts in lung lymphocyte profiles correlate with the sequential development of acute allergic and chronic tolerant stages in a murine asthma model.

T lymphocytes have a central regulatory role in the pathogenesis of asthma. We delineated the participation of lymphocytes in the acute allergic and chronic tolerant stages of a murine model of asthma by characterizing the various subsets of lymphocytes in bronchoalveolar lavage and lung tissue associated with these responses. Acute (10-day) aerosol challenge of immunized C57BL/6J mice with ovalbumin resulted in airway eosinophilia, histological evidence of peribronchial and perivascular airway inflammation, clusters of B cells and TCRgammadelta cells in lung tissue, increased serum IgE levels, and airway hyperresponsiveness to methacholine. In mice subjected to chronic (6-week) aerosol challenge with ovalbumin, airway inflammation and serum IgE levels were significantly attenuated and airway hyperresponsiveness was absent. The marked increases in lung B and T cell populations seen in the acute stage were also significantly reduced in the chronic stage of this model. Thus, acute ovalbumin challenge resulted in airway sensitization characteristic of asthma, whereas chronic ovalbumin challenge elicited a suppressed or tolerant state. The transition from antigenic sensitization to tolerance was accompanied by shifts in lymphocyte profiles in the lung and bronchoalveolar lavage fluid.

Confocal imaging of peripheral regions of intact rat lungs following intratracheal administration of 6-carboxyfluorescein, FITC-insulin, and FITC-dextran.

PURPOSE: This study compared the pulmonary disposition of 3 structurally diverse probe molecules following their intratracheal (i.t.) administration to anesthetized rats. METHODS: Following administration of 6-carboxyfluorescein (CF), FITC-insulin (FI) and FITC-dextran (FD), lungs were removed, inflated, perfused with a marker dye, and peripheral elements examined with confocal microscopy (CLSFM). RESULTS: At 5 min most of each probe remained within airspaces; the remainder distributed to interstitium, capillaries, Type II cells, and macrophages. At 60 min disposition differed significantly among probes. The smallest (CF, 376 Da) had almost completely exited air-spaces and was found primarily in extracellular interstitial spaces, often behind Type II cells. Disposition was consistent with both entry into peripheral lymphatics and association with peripheral fibers. FI and FD (6 and 10 kDa, respectively) were retained substantially longer within airspaces. In contrast to CF, FI appeared to localize along septal and peripheral fibers, but its disposition was inconsistent with the involvement of peripheral lymphatics. CONCLUSIONS: While all probes were < or = 10 kDa, there was considerable disparity among both their rates of absorption and subsequent disposition within peri-alveolar elements. CLSFM appears to be a useful ancillary tool for studying the pulmonary absorption of drugs and macromolecules.

Neutrophil apoptosis during the development and resolution of oleic acid-induced acute lung injury in the rat.

The oleic acid (OA) model of acute lung injury in rats is characterized by a massive and rapid influx of polymorphonuclear neutrophils (PMN) within 1 h, with a peak inflammatory response at 4 h and resolution by 72 h. We hypothesized that PMN apoptosis is involved in the resolution of OA-induced acute lung injury. To test this hypothesis, healthy adult Fischer 344 rats were given 30 microl OA in 0.1% bovine serum albumin (BSA) intravenously; controls were given BSA alone and killed at 1, 4, 24, and 72 h after OA to obtain bronchoalveolar lavage fluid (BALF) and lung tissue. Cell pellets from BALF and formalin-fixed, paraffin-embedded tissue section samples were processed for terminal deoxyribonucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) to identify apoptotic cells. Propidium iodide was used to counterstain nuclei. Percentage of nuclei undergoing apoptosis was counted under a fluorescent microscope. Control rats showed only resident alveolar macrophages (AM) in the BALF with no apoptosis. At the peak of injury, 1 h and 4 h after OA injection, we observed a massive PMN response without any evidence of apoptosis. At 24 h, when the OA injury is clinically and histologically in early resolution, we observed intense apoptosis of PMN nuclei along with evidence of apoptotic bodies in the cytoplasm of AM. Some of the AM also showed apoptotic nuclei at 72 h. Similar observations were made in the lung tissue sections. The results of the TUNEL assay were confirmed by DNA ladders and electron microscopy. We conclude that apoptosis of PMN and clearance by AM is an important mechanism in resolution of OA- induced acute lung injury.

Early detection of bleomycin-induced lung injury in rat using indium-111-labeled antibody directed against intercellular adhesion molecule-1.

UNLABELLED: We have investigated whether an (111)In-labeled mouse monoclonal antibody to rat intercellular adhesion molecule-1 ((111)In*aICAM-1) could detect lung injury early in rats treated with bleomycin. METHODS: Rats received an intravenous injection of either (111)In*aICAM-1 or (111)In-labeled normal mouse IgG ((111)In*nmIgG) and were imaged and killed 24 hr later. Lung injury was induced by an intratracheal injection of bleomycin 4 or 24 hr before the rats were killed. After death, tissue was removed and activity was measured, lungs were cryostat-sectioned to detect the presence of ICAM-1 by immunofluorescence, and the up-regulation of LFA-1alpha was examined on blood polymorphonuclear leukocytes (PMNs) using fluorescence-activated cell-sorter (FACS) analysis. RESULTS: In rats injected with (111)In*aICAM-1, the percent injected dose/organ in lungs both at 4 and 24 hr postbleomycin increased significantly compared to the values in either uninjured rats or rats that received (111)In*nmIgG. At 4 and 24 hr postinjury, the target-to-blood (T/B) ratio was 8/1 and 6/1, respectively. For (111)In*nmIgG, the T/B ratio at 4 hr was 0.5/1 and 0.4/1 at 24 hr. In (111)In*aICAM-1 rats injured at 4 or 24 hr, images could easily be distinguished from uninjured rats. All images of (111)In*nmIgG rats showed only cardiac blood-pool and liver activity with little lung activity. Lung ICAM-1 immunofluorescence intensity increased in the bleomycin-treated samples compared to uninjured lungs. Expression of LFA-1alpha on PMNs increased 19% and 210% at 4 hr and 24 hr postinjury, respectively, compared to control values. CONCLUSION: Biodistribution and imaging data demonstrate that (111)In*aICAM-1 can detect early acute bleomycin-induced lung injury. Immunofluorescence and FACS data suggest that (111)In*ICAM-1 uptake is a specific process. This antibody has potential as an early radionuclide detector of acute inflammations.

Role of tumor necrosis factor-alpha in the spontaneous development of pulmonary fibrosis in viable motheaten mutant mice.

The viable motheaten mutant mouse is severely immunodeficient and dies from a naturally occurring progressive pulmonary inflammation at approximately 10 weeks of age. The pulmonary disease is characterized by excessive macrophage accumulation in the lung and fibrosis. We correlated the development of lung injury in viable motheaten mice with tumor necrosis factor-alpha (TNF-alpha) levels in serum and lung. Significantly increased serum TNF-alpha levels were observed by enzyme-linked immunosorbent assay in viable motheaten mice at 4, 6, and 10 weeks of age as compared with normal control littermate mice. These ages correlated well with observed changes in lung wet weights, lung collagen content, and histological evidence of pulmonary inflammation and fibrosis. Qualitative assessment of lung tissue TNF-alpha levels was performed by immunohistochemical staining using immunoperoxidase techniques. These studies revealed increased levels of TNF-alpha in macrophage-like cells in viable motheaten mice from 5 to 10 weeks of age as compared with littermate control animals. Alveolar macrophages isolated from viable motheaten mice produced significantly greater amounts of TNF-alpha when stimulated with lipopolysaccharide compared with alveolar macrophages from control animals. In addition, administration of anti-TNF-alpha antibody to motheaten bone marrow recipient mice decreased the severity of acute lung injury. The results demonstrate a close correlation between the development of pulmonary injury and TNF-alpha levels in this model of spontaneously developing fibrotic lung disease.

Murine cytomegalovirus replication in the lungs of athymic BALB/c nude mice.

Murine cytomegalovirus (MCMV) infection in the lungs of T cell-deficient athymic BALB/c (Nu/ Nu) mice and their immunocompetent heterozygous (Nu/+) littermates was examined. Following intranasal inoculation, MCMV replicated in the lungs of both Nu/Nu and Nu/+ mice, but virus titers were significantly higher in T cell-deficient mice. After subcutaneous inoculation, virus disseminated to lung tissue of athymic mice, leading to progressive MCMV replication in lungs that was not seen in the immunocompetent mice. Athymic mice failed to develop an antibody response to MCMV. Histologically, athymic mice uniformly developed focal interstitial cellular aggregates adjacent to blood vessels or airways, which progressively enlarged and coalesced. Pneumonitis was not seen in the lungs of any Nu/+ mice. Thus, MCMV can replicate in the lungs without pneumonitis in immunocompetent mice, but MCMV produces a progressive focal pneumonitis during deficiency of T cell-mediated immunity.

A diether phosphonolipid surfactant analog, DEPN-8, is resistant to phospholipase-C cleavage.

Increased activities of phospholipase A2 and C (PLC) have been observed in the bronchoalveolar lavages of patients with adult respiratory distress syndrome (ARDS). DL-alpha-Di-O-hexadecylphosphonocholine [(R)(S)-DEPN-8], a surfactant analog of superior surface activity to the major lung surfactant phospholipid, dipalmitoylphosphatidylcholine (DPPC), is not a substrate for phospholipases A1, A2 and D, but is a substrate for PLC. (R)(S)-DEPN-8 was found in vitro to undergo significantly less PLC-catalyzed degradation as compared to DPPC. The results suggest that (R)(S)-DEPN-8 and structurally related analogs may be useful as components of exogenous replacement surfactant formulations for the treatment of ARDS-related lung injuries.

Alterations in surfactant neutral lipid composition during the development of bleomycin-induced pulmonary fibrosis.

The purpose of this investigation was to correlate changes in the neutral lipids of pulmonary surfactant with previously observed changes in surfactant phospholipids and lung compliance in the rat model of bleomycin-induced pulmonary fibrosis. Bronchoalveolar lavage fluid (BAL) obtained at 0, 1, 3, 7, 14, 30 and 120 days after transtracheal instillation of bleomycin was used as a source of surfactant lipids. The mean concentration of neutral lipids in normal BAL was 439 nmol/lung and was composed of 55% cholesterol (CHO), 27% cholesterol ester (CE) and 19% free fatty acids (FFA). CHO was elevated at 1 day, reaching a maximum 4-fold increase in concentration at 14 days before subsiding to normal at 120 days. In contrast to CHO, CE and FFA were significantly reduced at 1 day after bleomycin with FFA below detectable levels. However, both these species were twice normal levels at 3-30 days before returning to normal at 120 days. The fatty acid composition of CE did not change; however, unsaturated fatty acids were significantly increased in FFA between 3 and 120 days. The data indicate that there are significant alterations in the neutral lipid composition of pulmonary surfactant at various stages of bleomycin induced lung injury. The significance of these changes are not fully understood; however, the possibility exists that an abnormal surfactant results which in turn affects lung function.

Biodistribution of indium-111-labeled antibody directed against intercellular adhesion molecule-1.

UNLABELLED: We examined the biodistribution in normal rats of an 111In-labeled mouse monoclonal antibody to rat intercellular adhesion molecule-1 (111In-alCAM-1), as a potential detector of inflammation. METHODS: Indium-111-alCAM-1 or 111In-labeled normal mouse polyclonal immunoglobulin G (111In-nmIgG) was injected into rats. Groups of three to four rats were killed up to 18 hr after injection, and activity was measured in various tissues. Rats were also imaged at 1 and 18 hr after injection. RESULTS: Uptake of 111In-alCAM-1 was greatest in the lung (approximately 10% injected dose [ID]/g at 15 min) and then declined steadily (to approximately 2% ID/g at 18 hr). Lung uptake of 111In-nmIgG was eightfold less than that for 111In-alCAM-1 and did not change throughout the 18 hr. At all time points, blood activity for 111In-alCAM-1 was only 30% to 40% of that for 111In-nmIgG, whereas the percent injected dose per gram was increased more than twofold in the major organs. Compared with 111In-nmIgG, the 111In of alCAM-1 was shifted from the blood and was distributed among the lung kidney, spleen and liver. CONCLUSION: Indium-111-alCAM-1 may be useful as an early inflammation detection agent. Intercellular adhesion molecule-1 upregulation is a very early event in inflammation and rapid removal from the blood of this antibody provides low background in contrast to the usual high background with whole antibodies.