Granulomatous Hypersensitivity Research Articles

Establishment and characterization of an antigen-specific T-cell line from liver granulomas of Schistosoma mansoni-infected mice.

Granulomatous inflammations in schistosomiasis mansoni are the result of T-cell-mediated reactions to soluble egg antigens (SEA) secreted by parasite ova. To study TDH effector cell function, a granuloma T-cell line was established from collagenase-digested liver granulomas of acutely infected CBA/J mice. Dispersed nonadherent granuloma cells were cultured with feeder layer cells and SEA or with feeder layer cells alone in alternate cycles for 32 weeks. The granuloma T-cell line was L3T4+ Lyt-1+. In vitro, the SEA-stimulated T cells showed proliferation and interleukin 2 production. One million T cells adoptively transferred SEA-specific footpad swelling, and 7.5 X 10(6) T cells adoptively transferred granulomatous hypersensitivity to injected ova or SEA-coated beads. Anti-L3T4 monoclonal antibody blocked the SEA-specific cell proliferation. Depletion of L3T4+ cells abrogated, while that of Lyt-1+ cells diminished the adoptive transfer of SEA-specific footpad swelling. These experiments demonstrate that the granuloma T-lymphocyte population contains TDH-type effector cells. Establishment of an SEA-specific granuloma T-cell line will allow the study of the effector functions of the hitherto uncharacterized intralesional granuloma T lymphocyte.

In vitro and in vivo evidence that autoimmune reactivity to collagen develops spontaneously in Schistosoma mansoni-infected mice

Egg-induced granuloma formation in murine schistosomiasis mansoni results from vigorous anti-parasite reaction by activated T cells, macrophages, eosinophils, and fibroblasts. The present study suggests that strain-specific, autoimmune T-cell reactivity directed against host matrix proteins might also contribute to granulomatous hypersensitivity. T cells from infected C57B1 6 , but not from CBA or BALB c mice, proliferative in vitro in response to denatured collagen. T cells from uninfected mice, previously immunized with soluble egg antigen (SEA), did not respond in vitro to collagen. Spleen cells from acutely infected mice, but not chronically infected or uninfected animals, formed granulomas around collagen-coupled polyacrylamide beads in vitro. This response was blocked by anti-collagen antibodies that had no inhibitory effect on in vitro granuloma formation around SEA-coupled beads. In related in vivo studies, granuloma formation was quantitated after iv injection of SEA-, collagen-, or uncoated beads into normal or infected recipients. The mean diameter of lung granulomas induced by collagen-coupled beads in infected mice was significantly greater than the diameter of granulomas around either collagen beads in uninfected mice or uncoated beads in infected mice. These observations indicate that anti-collagen responses develop spontaneously in Schistosoma-infected mice and suggest that such reactivity might play a secondary role in granuloma formation and the pathogenesis of hepatic fibrosis.

Postgranulomatous anetoderma associated with Takayasu's arteritis in a child

• Takayasu's arteritis (TA) is a rare chronic inflammatory arteriopathy affecting mainly the aorta and its branches. Many skin manifestations have been reported in association with this disease. Pyoderma gangrenosum and subcutaneous inflammatory lesions of the leg are the most frequent. We studied a boy with TA in whom a papular rash of the trunk preceded the onset of vascular symptoms by many years. Histologically, the lesions were superficial and consisted of middermal noncaseating tuberculoid granulomas, which progressed to atrophy and anetoderma because of elastic network disruption. Granulomas were also found in synovial tissue but not in a temporal artery biopsy specimen, which showed only intimal hyperplasia. Our observations suggest that vascular and skin lesions with elastic tissue may both result from a common granulomatous hypersensitivity process. (<i>Arch Dermatol</i>1987;123:796-800)

Induction of granuloma-dependent angiotensin-converting enzyme and eosinophil chemotactic factor in the skin of athymic nude mice.

Activities of angiotensin-converting enzyme (ACE), other proteinases, and eosinophil chemotactic factor (ECF-G) are known to be elevated in hepatic hypersensitivity granulomas of thymus intact (nu/+) mice after Schistosoma mansoni infection. The enzyme activities also increase, but to a lesser degree in hepatic granulomas of athymic nude (nu/nu) mice, and ECF-G is not detectable. In this study isolated hepatic granulomas from nu/+ mice were grafted into the skin of uninfected nu/nu mice, and changes in those cellular functions were determined to examine whether the newly formed granulomas by recipient nu/nu cells acquire the functional activities as well as the histological appearance of nu/+ granulomas. ACE and ECF-G rapidly disappeared from grafted sites during the first 5 days, corresponding to loss of nu/+ cells from the graft. Reduction in activities of arylsulfatases, lysozyme, and acid phosphatase also occurred, but to a lesser extent. Recovery of ACE and ECF-G activities to the levels seen in nu/+ hepatic granulomas was observed by 14 days after grafting when nu/nu cells had accumulated in the grafts and formed new granulomas. Other enzymes increased to approximately half the levels seen in grafted donor granulomas. Circulating eosinophilia also increased. The findings indicate that nu/nu cells that accumulated in the skin grafts not only morphologically mimicked nu/+ type granulomas but also demonstrated nu/+ levels of cellular function. Analysis of skin granulomas developing in nu/+ mice after grafting of nu/+ hepatic granulomas showed the similar histology and enzymatic changes, whereas the skin sites inoculated with purified schistosome eggs alone caused neither significant histological changes nor elevation of ACE activity.

Granulomatous hypersensitivity to Schistosoma mansoni egg antigens in human schistosomiasis. I. Granuloma formation and modulation around polyacrylamide antigen-conjugated beads.

We have developed an in vitro model of granuloma formation for the purpose of studying the immunological components of delayed type hypersensitivity granuloma formation in patients infected with Schistosoma mansoni. Our data show that 1) granulomatous hypersensitivity can be studied by examining the cellular reactivity manifested as multiple cell layers surrounding the antigen conjugated beads; 2) this reactivity is a CD4 cell dependent, macrophage dependent, B cell independent response and 3) the in vitro granuloma response is antigenically specific for parasite egg antigens. Studies designed to investigate the immune regulation of granulomatous hypersensitivity using purified populations of either CD4 or CD8 T cells have demonstrated the complexity of cellular interactions in the suppression of granulomatous hypersensitivity. The anti-S. mansoni egg immune responses of individual patients with chronic intestinal schistosomiasis can be classified either as soluble egg antigen (SEA) hypersensitive with maximal granulomatous hypersensitivity or SEA suppressive with activation of the T cell suppressor pathway with effective SEA granuloma modulation. Our data suggest that T cell network interactions are active in the generation of effective granuloma modulation in chronic intestinal schistosomiasis patients.

Bronchoalveolar lavage.

In formulating a reasonable position about the clinical use of BAL and its analysis, one must acknowledge that it is still an experimental procedure that needs further assessment, and it must continue to be included as part of patient research protocols. Therefore, neither the patient nor his/her insurance carrier should foot the bill, yet. The cost involved in analysis of BAL fluid and serum raises another consideration about how many things need to be measured and what tests give the essential information and are the most discriminating. Clearly, all of the assays suggested by some of the BAL results given in table 2 are not necessary. The cell count and the differential count, indicating the relative percentage of lymphocytes among the respiratory cells, and monoclonal antibody staining to distinguish the various T-cell subtypes give most of the essential cell information that relates to activity of alveolitis and to diagnosis in the interstitial lung diseases. Finding a very high percentage of lymphocytes in BAL fluid shifts the differential diagnosis in an unknown diffuse interstitial lung disease to the possibility of a granulomatous process, especially sarcoidosis or hypersensitivity pneumonitis; whereas elevated PMN with about 3% eosinophils also present suggests possible idiopathic pulmonary fibrosis. Many of the protein and enzyme assays have a role in describing immunopathogenesis, but are rarely measured until a few days after the procedure. Some quite sophisticated cell mediators can be measured, such as interleukin-2 produced by helper T-lymphocytes and many macrophage effector substances that may give more precise information than just cell counts and various immunoglobulin values. These assays require complex biochemical and cell culture work and are only available in special research laboratories, limiting the availability of such tests. Thus, it is not easy to suggest just what tests should be conducted with BAL cells and fluid to tailor costs yet give comprehensive clinical information, too. The use of BAL to obtain cells and proteins lining the alveolar space in many ways is still in its infancy, and new applications are being sought for a substantial list of lung diseases. Just the tip of the iceberg has been investigated, and much more may remain to be uncovered.

マクロファージのプラスミノーゲン・アクチベーター分泌に及ぼすリンフォカインの刺激効果

In our previous study, we have demonstrated that plasminogen activators (PAs) with Mr=24, 000 and Mr=48, 000 play an important role in tissue fibrinolysis during the development of hypersensitivity granulomas. In order to investigate the cellular source of these PAs, we cultured mouse peritoneal macrophages in different conditions. C57BL/6N mice were used with or without infection by Mycobacterium lepraemurium. Antigen stimulated peritoneal exudate macrophages were obtained by intraperitoneal injection of sonicated M. lepraemurium to the infected mice. PA activity in conditioned media was assayed by using two-stage colorimetric method and electrophoretic enzymography. Resident peritoneal macrophages secreted PA with Mr=48, 000. However antigen stimulated peritoneal exudate macrophages secreted a high activity of PA with Mr=24, 000 in addition to Mr=48, 000. In order to investigate secretion mechanism, in vitro stimulation of macrophages was carried out by lymphokines which were obtained from culture supernatants of splenic cells exposed with antigen or splenic T cells with Concanavalin A. The results clearly demonstrated that macrophages became secretable of PA with Mr=24, 000 by lymphokine stimulation. Further experiments showed that the effect of lymphokine to induce secretion of PA was partially represented by γ-Interferon. These data indicated that the immunological stimulation induced macrophages to secrete PA, the molecular weight of which was altered from resident macrophages.

Pseudomelanoma of the Iris in Herpes Simplex Keratoiritis

A 37-year-old white man with a long history of recurrent herpetic keratitis presented with a rapidly enlarging pigmented iris lesion. The primary diagnostic concern was that the lesion might be a malignant melanoma. A biopsy of the mass was done and proved it to be a granuloma with granulomatous arteritis and infarction of the iris. In a patient with a history of recurrent ocular inflammation, such a hypersensitivity granuloma should be considered in the differential diagnosis of iris melanoma.

Study of some immunopharmacological properties of praziquantel in experimental schistosomiasis mansoni.

The immunopharmacological properties of praziquantel were studied in mice infected with Schistosoma mansoni. Hepatic granuloma measurement was the main parameter of assessment. Delayed foot pad swelling as an in vivo correlate for the delayed granulomatous hypersensitivity reaction was also determined. Fluorescent direct antigen-antibody reaction in the granuloma together with the immediate foot pad swelling were used to test for the humoral immune response. Praziquantel administered at seven weeks after infection in two dose regimens (3 X 250 mg kg-1 for three consecutive days and 3 X 83 mg kg-1 given four hourly within the same day was more or less equally effective in reducing the size of hepatic granuloma by 37-41% two weeks after treatment and by 81-85% one month after treatment. Delayed foot pad swelling using soluble egg antigen (SEA) was significantly suppressed one month after treatment by 53%. At nine weeks after infection the fluorescent antigen-antibody reaction in the granuloma was positive in the untreated controls, but at the same time (i.e. two weeks after treatment) it was negative in the praziquantel-treated mice. One month after treatment positivity was less compared to infected control mice. Reduction in worm burden, hepatic shift of the worms and the reduced number of ova per gram of tissue denoted the efficacy of the drug in its two dose regimens against the Egyptian strain of S. mansoni.

Mechanisms of suppressed cell-mediated immunity and impaired antigen-induced interleukin 2 production in granuloma-bearing mice.

Pulmonary granulomas were induced in BALB/c mice immunized with methylated bovine serum albumin in complete Freund's adjuvant by the intratracheal injection of plain agarose beads or beads conjugated to specific antigen. Large hypersensitivity granulomas developed around antigen-coupled beads in immunized animals. Smaller but still prominent granulomatous reactions developed around plain beads in immunized mice. In nonimmunized animals, both plain and antigen conjugated beads produced very small granulomas. Granuloma formation in sensitized animals was associated with suppressed delayed-type hypersensitivity reactions induced by the footpad injection of specific and nonspecific antigens. Lymph node cells from sensitized granuloma-bearing mice with cutaneous anergy showed suppressed specific and nonspecific antigen-induced proliferative responses in vitro. These cells also showed suppressed interleukin 2 production in response to specific antigen. Although no soluble suppressive factor was detected in granuloma extracts, suppressor cells were found in lymph nodes of granuloma-bearing mice, which could inhibit antigen-induced production of interleukin 2 by lymph node cells from immunized mice. Antigen-specific immunoglobulin G antibody production was not suppressed in immunized granuloma-bearing mice. Previous studies from our laboratory have demonstrated migration inhibition factor and interleukin 1 activities in aqueous extracts prepared from granuloma-bearing lungs of immunized mice. These results and the findings reported here indicate that granuloma formation and the associated anergy observed in this system are primarily expressions of cell-mediated immunity; selective suppression of in vivo and in vitro expressions of cell-mediated immunity in granuloma-bearing mice may be due to impaired antigen-induced interleukin 2 production; and such impairment is caused by suppressor cells.

Detection of granuloma-associated plasminogen activator in experimental murine schistosomiasis

Hypersensitivity granulomas induced by infection with Schistosoma mansoni were isolated from the livers of BALB c mice after 7, 8, 10, and 12 weeks. The parasite egg-granulomas were sequentially extracted with a Tris-buffered saline (soluble fraction) and 2 M KSCN (bound fraction). Fibrinolytic enzyme activity measured with both synthetic substrates and fibrin plates demonstrated an elevated level of plasminogen activator activity in the bound fraction 7–8 weeks after infection when mature granulomas first began to appear, followed by a gradual decrease 10–12 weeks after infection. An electrophoretic enzymography technique revealed multiple molecular species of plasminogen activator at M r = 95K, 74K, 60K, 45K, and 24K. The bands with M r = 45K and 24K were found compatible with the electrophoretic pattern of macrophage-plasminogen activator. When the granulomas reached maximum size after 10 to 12 weeks, the plasminogen activator with 45K and 24K diminished, while plasminogen activator activity at M r = 95K, 74K, and 60K remained unchanged suggesting the presence of both vascular and tissue types of plasminogen activators. There was no urokinase-type plasminogen activator detectable in granulomas at any time. In the soluble fraction no enzymatic activity was found, whereas regulating inhibitor activity for plasminogen activator was consistently detectable.

In vitro delayed hypersensitivity granuloma formation: development of an antigen-coated bead model.

Previously, we have described an in vitro model of granulomatous hypersensitivity around Schistosoma mansoni eggs in both the murine model of schistosomiasis and in human schistosomiasis. These studies describe a new model of in vitro granuloma formation that complexes soluble egg antigen from S. mansoni eggs, a partially purified protein derivative of Mycobacterium tuberculosis (PPD), or bovine serum albumin to carrier beads. Ultrastructural and morphologic evaluations demonstrate that there are initial macrophage interactions, followed by the recruitment of antigen-specific T cells that interact with and recruit macrophages, lymphocytes, granulocytes, and fibroblasts. Finally, there is a stage of granulomatous organization involving fibroblast proliferation and collagen deposition. The in vitro reactivity, defined by a quantitative granuloma index, correlates with in vivo granulomas around S. mansoni eggs in the livers of infected cell donor animals. In vitro granuloma formation against PPD-coated beads correlated with delayed cutaneous hypersensitivity against PPD, which was judged by footpad swelling. The reactions demonstrate antigenic specificity and were intrinsically modulated in a manner that is analogous to that previously shown with the in vitro egg granuloma model. This model of in vitro granuloma formation promises to be a useful tool for elucidating mechanisms of cellular immunity and regulation.

Glycopeptides in soluble egg antigen of Schistosoma mansoni: isolation, characterization, and elucidation of their immunochemical and immunopathological relation to the major egg glycoprotein (MEG).

The major egg glycoprotein (MEG) of Schistosoma mansoni was purified by ion-exchange chromatography of glycoprotein fraction obtained from soluble egg antigen (SEA) by lectin affinity chromatography. Small carbohydrate-rich fragments (CRF) contained in the glycoprotein fraction of SEA were isolated by ultrafiltration followed by dialysis (10 to 13 kd). Comparison of MEG and CRF yielded the following results: purified MEG (70 kd) contains about 77% carbohydrate, and CRF contains 92.5% carbohydrate. When radioiodinated and run by SDS-PAGE, each yielded a single band with respective Rf values of around 0.33 and 1.0 CRF is capable of inhibiting, in a Farr-type RIA, the binding of 125I-MEG to serum from chronically infected mice. Furthermore, CRF and MEG exhibit a single and continuous line of radioimmunodiffusion. CRF, unlike SEA, SEA glycoproteins, or purified MEG, is incapable of eliciting delayed footpad swelling in egg-sensitized mice or of inducing granulomatous hypersensitivity, when given at amounts equivalent to or higher than MEG by protein or carbohydrate content. Thus, whereas SEA, SEA glycoproteins, or MEG elicited in a representative test net swelling of 0.28 mm, 0.34 mm, and 0.29 mm, respectively, CRF gave net swellings of 0.06 mm, similar to the control value (0.07 mm) in unsensitized mice. Also, mice sensitized to viable eggs, SEA, or purified MEG exhibited, after i.v. challenge with viable eggs, a mean area of granulomas in the lungs of 12,389 micron2, 16,412 micron2, and 12,354 micron2, respectively, as compared with 7940 micron2 in CRF-sensitized mice and 8428 micron2 in unsensitized control mice. Thus, CRF appears to contain fragments of MEG that are serologically active but immunopathologically inactive at the concentrations used.

Role of interleukin 1 in experimental pulmonary granuloma in mice.

Pulmonary granulomas were induced in immunized BALB/c mice by the intratracheal injection of antigen-coated and plain agarose beads. Prominent lesions developed within 24 hr, reached peak intensity within 3 days, and gradually declined in size thereafter. The hypersensitivity granulomas induced in sensitized mice by antigen-coated beads were much larger than the lesions induced by plain beads. Minimal inflammation was produced in unsensitized mice injected with antigen-coated or plain beads. Aqueous extracts prepared from pulmonary granuloma lesions induced in sensitized mice by antigen-coated beads contained high levels of interleukin 1 (IL 1) and migration inhibition factor (MIF) activities. The kinetics of appearance of these mediators were similar. Lower but detectable activity of both mediators was detected in extracts prepared from sensitized mice injected with plain beads. Neither interleukin 2 (IL 2) nor IL 2 neutralizing activities were detected in the extracts. The presence of IL 1 and MIF in extracts prepared from early and peak pulmonary granulomatous lesions suggests that these soluble factors are produced by cells within the lesions, and that they are involved in mediating the expression and/or maintenance of the granulomas.

Delayed type hypersensitivity granuloma formation around Schistosoma mansoni eggs in vitro. IV. Granuloma formation in human schistosomiasis.

Peripheral blood mononuclear cells, obtained from 42 school-age Egyptian children, were isolated on Ficoll-hypaque density gradients and assayed for granuloma formation. A granuloma index (G.I.) which classified the cellular reactions to Schistosoma mansoni eggs was determined for each patient. Morphologic criteria to assess the cellular reactivity included cell adherence, blast cell transformation, cell migration, and circumoval accumulation of inflammatory cells around the egg. The difference between the mean granuloma index of uninfected controls (G.I. = 1.25 +/- 0.04) and infected patients (G.I. = 1.58 +/- 0.05) was statistically significant (P less than 0.01; Student's t-test). There was no correlation between the granuloma indices and infection intensities determined by quantitative egg counts or between anti-major serological antigen antibody titers. These data demonstrate the feasibility of studying granulomatous hypersensitivity in human schistosomiasis utilizing an in vitro model of granuloma formation and peripheral blood cells.

Host granulomatous response in schistosomiasis mansoni. Antibody and cell-mediated damage of parasite eggs in vitro.

In chronic schistosomiasis mansoni the major pathologic lesions are granulomas surrounding eggs deposited in host tissues. Parasite ova release antigenic material that sensitize the host, resulting in the development of delayed-type hypersensitivity granulomas. The objectives of the present study were to assess the ability of components of the host granulomatous response to induce biochemical and biologic alterations in eggs in vitro, and to correlate these with the capacity of ova to induce granulomas in vivo. An assay of egg tricarboxylic acid cycle activity was developed by use of 2-[14C]acetate as substrate and measurement of accumulation of released 14CO2. Addition of human granulocytes (96% neutrophils, 4% eosinophils) to eggs (cell/egg ratio 1,000:1) and heat-inactivated normal human serum reduced predicted egg 14CO2 generation by 15.6 +/- 3.0%. This effect was greater in the presence of sera of subjects with schistosomiasis (25.6 +/- 2.8% reduction) or when complement was present (24.4 +/- 4.0%). Autologous eosinophils and neutrophils were equally effective in decreasing egg 2-[14C]acetate metabolism (25.6 and 21.4% reductions, respectively). Since the biological role of schistosome eggs relates to their ability to hatch and produce miracidia, we evaluated the effect of granulocytes and sera on this function. The hatching rate of eggs incubated with normal serum was 52.8 +/- 3.3 miracidia/100 eggs; this value decreased to 37.0 +/- 2.6 when granulocytes were added (P less than 0.01). Granulocytes plus antibody- or complement-containing sera led to hatching rates of 23 and 20 miracidia/100 eggs. When ova were pre-incubated with granulocytes and various sera and injected into mice, the areas of egg-induced pulmonary granulomas measured 8 d later were reduced 32 to 45% as compared with lesions elicited by parasite eggs not exposed to granulocytes. Exposure of antigen-coated Sepharose beads to granulocytes and immune serum before injection into mice also led to a reduction in granuloma formation as compared with beads pre-incubated with serum alone. These data indicate that granulocytes in conjunction with antibodies and complement inflict biologically relevant toxic effects on eggs that are manifest in vivo by a decreased ability to elicit granulomas.

Delayed hypersensitivity granuloma formation around Schistosoma mansoni eggs in vitro. III. Granuloma formation and modulation in human Schistosomiasis mansoni.

An in vitro model of granuloma formation was used to study the cellular immune responses of Schistosoma mansoni-infected patients. The purposes of this study were to determine the relationship of granulomatous hypersensitivity to S. mansoni eggs in recent, well-defined infections and long-term chronic infections, and to determine the role of T cell subsets (OKT3, 4, and 8) defined by monoclonal antibodies in granulomatous hypersensitivity. Peripheral blood mononuclear cells obtained from patients with recent S. mansoni infections demonstrated increased granulomatous hypersensitivity responses in vitro when compared to peripheral blood mononuclear cells obtained from patients infected for 5 yr or more. The selective removal of infected for 5 yr or more. The selective removal of OKT3+ or OKT4+ cells reduced the ability of peripheral blood mononuclear cells to form granulomas in vitro. Positive selection for OKT4+ T cells produced optimal granulomatous hypersensitivity when compared to that produced by the unfractionated peripheral blood mononuclear cell population. OKT8+ cells demonstrated no ability to form granulomas in vitro. Selective removal of OKT8+ T cells produced variable results in the ability of the remaining peripheral blood mononuclear cells to form granulomas in vitro. These studies demonstrate the feasibility of investigating granulomatous hypersensitivity and immunoregulatory mechanisms operative in S. mansoni-infected patients by using in vitro technology.

Granulomatous hypersensitivity and antibody production in response to antigens of Capillaria hepatica eggs

Soluble egg antigens of Capillaria hepatica were fractionated by gel filtration chromatography into two major protein peaks of 300,000 and 14,000 mol.wt. The unfractionated antigen and both peaks were capable of sensitizing mice to produce quantitatively larger liver granulomas upon experimental innoculation of eggs; the increase in granuloma size was related to the amount of antigen used to sensitize. The antibody response in C. hepatica infected mice was primarily directed toward the high molecular weight components. Comparison of these findings with those reported for the Schistosoma mansoni egg granuloma suggests a diversity in the mechanisms of granuloma formation among helminth parasites.

Role of lipoxygenase products in murine pulmonary granuloma formation.

Various arachidonic acid (AA) metabolites are known to regulate immune cell function(s) and dictate the progression of both acute and chronic inflammatory reactions. Using a model of Schistosoma mansoni egg-induced hypersensitivity granulomas, we have delineated the in vivo effects of inhibitors of cyclooxygenase (CO) and lipoxygenase (LO) pathways on granuloma development and granuloma macrophage I-region-associated (Ia) antigen expression. In addition, by high performance liquid chromatography (HPLC) we have profiled the metabolism of AA by macrophages that are isolated from granulomatous foci, and have biochemically characterized the in vitro specificity and activity of selected CO and LO inhibitors. The development of hypersensitivity-type pulmonary granulomas in mice was dramatically suppressed by inhibitors with anti-LO activity (nordihydroguairetic acid (NDGA), nafazatrom, and BW755c) in a dose-dependent manner, while indomethacin, which is primarily CO-selective, had no significant effect. Furthermore, NDGA and nafazatrom profoundly arrested the normal progression of preformed granulomatous lesions. The inhibitors of the LO pathway also suppressed the in vivo kinetics of Ia antigen expression by granuloma macrophages. In contrast, indomethacin augmented Ia-antigen expression. The major AA metabolites that were synthesized by the granuloma macrophages were shown to be leukotriene C4 and mono-hydroxyeicosatetraenoic acids. HPLC analysis of AA metabolites from granuloma macrophages that were treated with the various inhibitors confirmed that indomethacin was most CO-selective and NDGA most LO-selective. Nafazatrom and BW755c inhibited AA metabolism by both pathways. Notably, high concentrations of the compounds (5 X 10(-5) M) tended to suppress all products. Our results suggest that LO products may be important in the generation and maintenance of immune granulomatous inflammatory responses.

Role of oxygen reactive species in [formula omitted] egg-induced granulomatous inflammation

The role of oxygen reactive species in granulomatous hypersensitivity was explored using a model of pulmonary granulomas induced by intravenous injection of eggs from the parasite Schistosoma mansoni . Macrophages from sychronously developing lesions spontaneously released significant quantities of superoxide anion (26 nmoles/10 6/2h) by 8 days of development. In contrast, the non-T cell foreign body (Sephadex bead) granuloma macrophages produced only (2 nmoles/10 6/2h) small quantities. Daily administration of the oxygen scavenger, α-tocopherol, by either oral or parenteral routes caused up to 60% suppression of granuloma size. Moreover, parenteral administration of specific inactivators of O 2 − and H 2O 2, superoxide dismutase and catalase respectively, resulted in a 30 to 40% reduction in granuloma size. These data suggest that oxygen reactive species take part in the generation of hypersensitivity granulomas.