T lymphocyte-dependent evolution of bacterial cell wall-induced hepatic granulomas

Injection of streptococcal cell walls (SCW) i.p. into susceptible rats results in dissemination of SCW primarily to the liver, spleen, bone marrow, and peripheral joints. Within the liver, the SCW are phagocytized by the Kupffer cells, initiating a sequence of events leading to the formation of hepatic granulomas. The granulomas are characterized by large numbers of W3/13+, W3/25+ T lymphocytes and Ia+, esterase-positive macrophages. The generation of inflammatory mediators by these mononuclear cells appears to be central to the evolution of the granulomas and the subsequent fibrotic sequelae evoked by the SCW. In the absence of functional T lymphocytes (athymic rats), injection of SCW does not trigger lymphokine production, and organized granulomas do not develop in the livers. Furthermore, inhibition of T lymphocyte proliferation and lymphokine synthesis pharmacologically by cyclosporin A administration in euthymic animals inhibits SCW-induced hepatic granuloma development. Although macrophage function is apparently not impaired as evidenced by IL 1 and PGE2 production, a chronic inflammatory response to SCW cannot be sustained in the absence of T lymphocyte participation. These studies provide insight into the cellular and molecular mechanisms leading to formation and maintenance of chronic granulomatous lesions.     

Tetracyclines convert the osteoclastic-differentiation pathway of progenitor cells to produce dendritic cell-like cells

Tetracyclines, such as doxycycline and minocycline, are used to suppress the growth of bacteria in patients with inflammatory diseases. Tetracyclines have been shown to prevent bone loss, but the mechanism involved is unknown. Osteoclasts and dendritic cells (DCs) are derived from common progenitors, such as bone marrow-derived macrophages (BMMs). In this article, we show that tetracyclines convert the differentiation pathway, resulting in DC-like cells not osteoclasts. Doxycycline and minocycline inhibited the receptor activator of NF-κB ligand (RANKL)-induced osteoclastogenesis of BMMs, but they had no effects on cell growth and phagocytic activity. They influenced neither the proliferation nor the differentiation of bone-forming osteoblasts. Surprisingly, doxycycline and minocycline induced the expression of DC markers, CD11c and CD86, in BMMs in the presence of RANKL. STAT5 is involved in DC differentiation induced by GM-CSF. Midostaurin, a STAT5-signaling inhibitor, and an anti-GM-CSF-neutralizing Ab suppressed the differentiation induced by GM-CSF but not by tetracyclines. In vivo, the injection of tetracyclines into RANKL-injected mice and RANKL-transgenic mice suppressed RANKL-induced osteoclastogenesis and promoted the concomitant appearance of CD11c(+) cells. These results suggested that tetracyclines prevent bone loss induced by local inflammation, including rheumatoid arthritis and periodontitis, through osteoclast-DC-like cell conversion.     

Hepatic granulomas induced by Schistosoma mansoni in mice deficient for connexin 43 present lower cell proliferation and higher collagen content

Granuloma formation involves a coordinated interaction between monocytes and macrophages, epithelioid cells, lymphocytes, eosinophils, neutrophils and fibroblasts. It has been established that extracellular communication via cytokines is important for the assembly of granulomas. However, the importance of gap junctions and intercellular communication to granuloma formation and development had never been assessed. Connexins are proteins that form gap junctions, and connexin 43 (Cx43) is present in macrophages, lymphoid cells, myelogenous cells, fibroblasts and others. We analyzed the effect of heterologous deletion of Gja1 (Cx43 gene) on the formation and development of hepatic granulomas induced by Schistosoma mansoni eggs. Heterozygous (Cx43(+/-)) and wild-type (Cx43(+/+)) mice were infected subcutaneously with S. mansoni cercarie and evaluated after 6, 8 and 12 weeks. Granuloma cells express Cx43, as revealed by real-time PCR in isolated granulomas, and by immunohistochemistry. Cx43 expression was reduced in Cx43(+/-) mice, as expected. No differences in the average area of granulomas or number of cells per granuloma were observed between mice of different genotypes. However, granuloma cells from Cx43(+/-) mice displayed a reduced index of the proliferating cell nuclear antigen (PCNA) labeling at 8 and 12 weeks post-infection. Moreover, Cx43(+/-) granulomas unexpectedly presented a higher degree of fibrosis, quantified by morphometric analysis in Sirius Red-stained slides. Our results indicate that the deletion of one allele of the Cx43 gene, and possibly the reduced gap junction intercellular communication capacity (GJIC), may impair the interactions between granuloma cells, reducing their proliferation and increasing their collagen content, thereby modifying the characteristics of S. mansoni granuloma in mice.     

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.     

Sequential Involvement of NK Cells and CD8+ T Cells in Granuloma Formation of Rhodococcus aurantiacus-Infected Mice

We investigated the effect of in vivo administration of antibodies against T-cell subsets and natural killer (NK) cells on endogenous gamma interferon (IFN-γ) production and granuloma formation in Rhodococcus aurantiacus-infected mice. High titers of endogenous IFN-γ were detected in the extracts of the livers and spleens during 24 hr of the infection, reaching the peak at 8 hr, and the IFN-γ production was reduced by in vivo administration of anti-NK 1.1 monoclonal antibody (MAb) or antibody against asialo GM1⁺ cells. Endogenous IFN-γ declined until 2 days of the infection, then reappeared from 1 week and peaked at 3 weeks. Endogenous IFN-γ at 1 and 3 weeks was reduced by in vivo administration of anti-CD8 MAb, but not by anti-CD4 MAb or anti-NK 1.1 MAb. Granulomatous lesions in the livers and spleens began to appear from 1 week of the infection and developed in 3 weeks. In vivo administration of rat anti-IFN-γ MAb reduced the development of granulomas. In addition, granuloma formation was reduced by depletion of NK cells prior to the infection or depletion of CD8⁺ T cells at 1 week of the infection. Based on these findings, it is presumed that the biphasic production of IFN-γ is attributable to NK cells in the early phase of the infection and CD8⁺ T cells in the phase of granuloma formation, and that granuloma formation is regulated by NK cells and CD8⁺ T cells through the secretion of endogenous IFN-γ.     

Adoptive suppression of granuloma formation by T lymphocytes and by lymphoid cells sensitive to cyclophosphamide.

Egg-induced granulomas formed in mice with chronic Schistosoma mansoni infection are smaller than those which develop during early (8-week) infection. Adoptive transfer of spleen cells from chronically infected mice (15–25 week), which displayed modulated granulomas, to 6-week-infected recipients effectively suppressed active granuloma formation in the recipients by 8 weeks after infection. Pretreatment of these suppressive spleen cells with anti-Thy 1.2 serum and complement eliminated their suppressive capacity. Administration of cyclophosphamide (CY) (20 mg/kg, 3 times/week for 3 weeks) to 12- to 15-week-infected mice reversed modulation of granuloma formation resulting in larger granulomas at 15 weeks. This abrogation of suppression was reflected in the spleens of the CY-treated mice, as seen by the inability of their spleen cells to adoptively transfer suppression to 6-week-infected mice. This regimen of CY treatment did not significantly alter anti-schistosome egg antigen hemagglutinating antibody titers. It is reasoned that the modulation of granuloma formation observed during chronic schistosomiasis mansoni is in part dependent upon a T lymphocyte and a CY-sensitive spleen cell.     

The role of osteopontin in the development of granulomatous lesions in lung

Osteopontin (OPN) has been shown to be expressed by cells in granulomas of various origins, but whether it plays a functional role in granuloma formation is not known. Here we used a cardiomyopathic hamster (TO2) model, to test the hypothesis that OPN contributes functionally to granuloma development. We immunized cardiomyopathic and normal hamsters by subcutaneous injection of bovine serum albumin in complete Freund's adjuvant, and assessed various tissues for both OPN RNA expression and granuloma formation. Cardiomyopathic hamsters expressed OPN, and formed granulomatous lesions, in heart tissue in both immunized and untreated animals. In addition, immunization induced expression of OPN in lung and lymph nodes of cardiomyopathic (but not normal) hamsters, and also induced granuloma formation in these organs. To test whether OPN expression could play a functional role in inducing granulomas, we produced an adenoviral vector containing the murine OPN gene, and introduced this vector intratracheally into the lungs of normal hamsters. The OPN-containing vector, but not the control vector, induced pulmonary granuloma formation. These studies provided direct in vivo evidence that OPN can contribute functionally to the formation of granulomatous lesions, and suggest that OPN expression may be a common factor involved in formation of granulomas of various origin.     

Adherent-invasive Escherichia coli isolated from Crohn's disease patients induce granulomas in vitro

Adherent-invasive Escherichia coli (AIEC) have been shown to be highly associated with ileal Crohn's disease (CD). AIEC survive within infected macrophages, residing within the phagolysosomal compartment where they take advantage of the low pH to replicate extensively. We investigated whether, like the tuberculous bacillus which also persists within macrophages, AIEC LF82 induces the formation of granulomas, which are a common histopathological feature of CD. For this purpose, we have taken advantage of an in vitro model of human granulomas that we recently developed, based on blood-derived mononuclear cells. We demonstrated that AIEC LF82 induces aggregation of infected macrophages, fusion of some of them to form multinucleated giant cells and subsequent recruitment of lymphocytes. Light microscopy and scanning electron microscopy analysis of the cell aggregates confirmed their granuloma features. This was further confirmed by histological analysis of granuloma sections. Noteworthy, this phenomenon can be reproduced by soluble protein extracts of AIEC LF82 coated onto beads. Although the cell aggregates not completely mimic natural CD-associated granulomas, they are very similar to early stages of epithelioid granulomas.     

A regulatory effect of the balance between TNF-alpha and IL-6 in the granulomatous and inflammatory response to Rhodococcus aurantiacus infection in mice

After i.v. inoculation with Rhodococcus aurantiacus, wild-type (WT) mice develop nonnecrotic, epithelioid granulomas. Because a high level of TNF-alpha is observed during the initial phase postinfection, we examined the extent to which TNF-alpha contributes to granulomatous inflammation using TNF-alpha gene-deficient (TNF-alpha(-/-)) mice. Despite a lack of R. aurantiacus proliferation, TNF-alpha(-/-) mice displayed high mortality rates within 5 days postinfection, as well as a high level of IL-6 in their spleens. Histological examination showed an absence of granuloma formation in TNF-alpha(-/-) mice. Pretreatment of TNF-alpha(-/-) mice with rTNF-alpha failed to restore this granuloma formation but accelerated bacterial removal and cellular recruitment. This rTNF-alpha administration also attenuated IL-6 production, resulting in increased survival rates of TNF-alpha(-/-) mice. Heat-killed R. aurantiacus induced in vitro enhanced mRNA expression and production of IL-6 in macrophages and DCs from TNF-alpha(-/-) mice when compared with WT controls, and treatment of TNF-alpha(-/-) mouse cells with rTNF-alpha decreased the IL-6 secretion. Moreover, anti-TNF-alpha or anti-IL-6 treatment increased IL-6 or TNF-alpha production by WT mouse cells, respectively. These data suggest that the production of TNF-alpha and IL-6 can be negatively regulated by each other. Administration of rIFN-gamma to TNF-alpha(-/-) mice caused immature granulomas in livers, and treatment with both rTNF-alpha and rIFN-gamma led to the formation of mature granulomas. Overall, TNF-alpha appears crucial for bacterial clearance, cellular recruitment, and granuloma formation. The balance between TNF-alpha and IL-6 during the early phase of infection controls the development of the inflammatory response to R. aurantiacus infection.     

RNA biosynthesis in mitochondria under conditions of prolonged inhibition of protein biosynthesis in rat liver cytoplasm]

When cytoplasmic protein synthesis is inhibited by cycloheximide (CHI) in vivo synthesis of water-soluble mitochondrial proteins and of mitochondrial RNA is decreased. These changes measured in isolated rat liver mitochondria are similar to those observed in vivo and correlate with the changes the synthesis of water-soluble proteins in mitochondria. When the cytoplasmic fraction (30,000 g-supernatant) had been added to the mitochondria showing decreased RNA synthesis, the RNA synthesis increased to the control level (the incubation conditions were favourable for the protein transport from microsomes to mitochondria). RNA synthesis in mitochondria was not stimulated by cytoplasmic fractions from the CHI-pretreated rats. After prolonged dialysis these fraction stimulated RNA synthesis even to a greater extent than cytoplasmic fractions from the untreated animals. Mitochondrial RNA polymerase activity (measured in mitochondrial extracts supplemented with exogenous DNA) was higher in extracts of mitochondria from livers of normal rats than in extracts of mitochondria from livers of animals injected with CHI.     

Involvement of macrophage migration inhibitory factor (MIF) in experimental uric acid nephropathy

BACKGROUND: Deposition of uric acid in the kidney can lead to progressive tubulointerstitial injury with granuloma formation. We hypothesized that uric acid crystal deposition may induce granuloma formation by stimulating local expression of macrophage migration inhibitory factor (MIF), which is a known mediator of delayed type hypersensitivity (DTH). MATERIALS AND METHODS: A model of acute uric acid nephropathy was induced in rats by the administration of oxonic acid (an inhibitor of uricase), together with uric acid supplements. MIF expression and local cellular response were examined by in situ hybridization and immunohistochemistry. RESULTS: Kidney tissue examined at 35 days posttreatment showed widespread tubulointerstitial damage with intratubular uric acid crystal deposition and granuloma formation. Tubules within the areas of granuloma showed a six-fold increase in MIF mRNA, compared with uninvolved areas by in situ hybridization. Moreover, the areas of increased MIF mRNA expression correlated with sites of dense accumulation of macrophages and T cells, and these cells were activated when assessed by the expression of interleukin-2R (IL-2R) and (MHC) class II. Interestingly, cytoplasmic staining for MIF protein in the uric acid (UA) crystal-associated granulomatous lesions was reduced, indicating a rapid MIF secretion by damaged tubules and macrophages secondary to uric acid crystal stimulation. This was confirmed by the demonstration of a marked increase in urinary MIF protein by Western blot analysis. Control rats fed either a normal diet or only oxonic acid had no discernible evidence of renal disease by routine light microscopy and minimal tubular expression of MIF mRNA and protein. CONCLUSIONS: These data suggest that intrarenal granulomas in urate nephropathy may be the consequence of a crystal induced DTH reaction mediated by MIF.     

Inhibitory effects of glucocorticoids on collagen synthesis by mouse sponge granulomas and granuloma fibroblasts in culture.

The basis for the glucocorticoid-mediated decrease in tissue collagen was studied in mouse granulomas and in primary granuloma fibroblast cultures. Injection of mice for 12 days with dexamethasone (0.35 mg/kg body weight) resulted in a 50--70% inhibition of collagen synthesis and accumulation in polyvinyl sponge-induced granulomas whereas total protein synthesis was inhibited by only about 25%. The decreased collagen content of the granuloma was accounted for by both a reduced fibroblast number and diminished synthesis per cell. Growth rates, total protein synthesis and collagen synthesis were the same in granuloma fibroblast cultures derived from control or steroid-treated mice. However, addition of 3.10(-7) M hydrocortisone to the culture medium caused a 30--50% inhibition of both collagen and non-collagen protein synthesis in firbroblasts from either source. These inhibitory effects were dose- and time-dependent with a lag time of 12--24 h. Prolyl hydroxylase activity was reduced both in sponge granulomas from glucocorticoid-treated mice and in hydrocortisone-treated fibroblast cultures. However, protein synthesis was inhibited to the same extent as the inhibition of prolyl hydroxylase activity and there was no effect on peptidyl prolyl hydroxylation. These results indicate that the glucocorticoid-induced reduction of collagen synthesis and accumulation observed in mouse granulomas and primary granuloma fibroblast cultures is not specific for this protein. Furthermore, glucocorticoid-induced inhibition of collagen synthesis cannot be attributed to underhydroxylation of collagen prolyl residues.     

The biogenesis of rat liver mitochondrial ATPase. Subunit composition of the normal ATPase complex and of the deficient complex formed when mitochondrial protein synthesis is blocked.

1. An ATPase complex containing 12 subunits was isoalted from rat liver mitochondria. 2. In vivo inhibition of mitochondrial protein synthesis by the chloramphenicol analogue thiamphenicol leads to the formation of an oligomycin-insensitive membrane-bound ATPase complex in mitochondria of regenerating rat liver. 3. This oligomycin-insensitive, membrane-bound ATPase was isolated by the same procedure as the ATPase complex from regenerating livers of untreated animals. 4. SDS-polyacrylamide gel electrophoresis of in vivo labelled ATPase complexes from control and from thiamphenicol-treated rats reveals that three subunits out of the 12 are not synthesized or assembled when the mitochondrial translation activity is blocked. 5. From the subunits synthesized and assembled when mitochondrial pror (Fo) of the ATPase complex (subunit 5). 6. The oligomycin sensitivity-conferring protein seems absent in the ATPase complex formed in the presence of thiamphenicol.     

Identifying control mechanisms of granuloma formation during M. tuberculosis infection using an agent-based model

Infection with Mycobacterium tuberculosis is a major world health problem. An estimated 2 billion people are presently infected and the disease causes approximately 3 million deaths per year. After bacteria are inhaled into the lung, a complex immune response is triggered leading to the formation of multicellular structures termed granulomas. It is believed that the collection of host granulomas either contain bacteria resulting in a latent infection or are unable to do so, leading to active disease. Thus, understanding granuloma formation and function is essential for improving both diagnosis and treatment of tuberculosis. Granuloma formation is a complex spatio-temporal system involving interactions of bacteria, specific immune cells, including macrophages, CD4+ and CD8+ T cells, as well as immune effectors such as chemokine and cytokines. To study this complex dynamical system we have developed an agent-based model of granuloma formation in the lung. This model combines continuous representations of chemokines with discrete agent representations of macrophages and T cells in a cellular automata-like environment. Our results indicate that key host elements involved in granuloma formation are chemokine diffusion, prevention of macrophage overcrowding within the granuloma, arrival time, location and number of T cells within the granuloma, and an overall host ability to activate macrophages. Interestingly, a key bacterial factor is its intracellular growth rate, whereby slow growth actually facilitates survival.     

Liver lipase and high-density lipoprotein. Lipoprotein changes after incubation of human serum with rat liver lipase

Under standard conditions, liver regeneration is impaired if mitochondrial protein synthesis is completely blocked. By treating rats with oxytetracycline for various periods of time directly prior to partial hepatectomy, livers were led to a condition of relative deficiency in cytochrome c oxidase and ATP synthetase. To this end, oxytetracycline was administered by means of continuous intravenous infusion up to concentrations of 20 micrograms/ml serum, giving a gradual decrease in cytochrome c oxidase activity. This activity was used as a marker for functionally capable mitochondria and as a tool to monitor the efficiency of inhibition of mitochondrial protein synthesis. It is shown that liver regeneration is strongly impaired after a period of pretreatment of 22 days or more and continuation of oxytetracycline treatment during regeneration. The mitochondrial respiratory capacity is reduced to 14% of the control value under these conditions. To obtain inhibitory levels within the regenerating liver, it was necessary to raise the serum levels slightly above 20 micrograms/ml. This measure is most likely required because of the poor vascularization of the regenerating liver. The serum levels were kept, however, far below those known to inhibit cytoplasmic protein synthesis. The results show that in normal liver the respiratory capacity must be reduced drastically before energy-requiring processes become affected. In Zajdela hepatoma cells, similar effects are found after reduction of the cytochrome c oxidase activity to 38%. This difference in sensitivity is probably based on the different mitochondrial content of liver cells and the liver-derived Zajdela cells.     

An in vitro model of the leukocyte interactions associated with granuloma formation in Mycobacterium tuberculosis infection

The principal defense of the human host against a Mycobacterium tuberculosis infection is the formation of granulomas, organized collections of activated macrophages, including epithelioid and multinucleated giant cells, surrounded by lymphocytes. This granuloma can sequester and contain the bacteria preventing active disease, and if the granuloma is maintained, these bacteria may remain latent for a person's lifetime. Secretion of a variety of chemoattractant cytokines following phagocytosis of the bacilli by the macrophage is critical not only to the formation of the granuloma but also to its maintenance. To investigate this process of early granuloma formation, we developed an in vitro model composed entirely of human cells. Combining blood lymphocytes and autologous macrophages from healthy purified protein derivative skin test-negative individuals and mycobacteria resulted in the formation of small, rounded aggregate structures. Microscopic examination found macrophage-specific CD68(+) epithelioid macrophages and small round CD3(+) lymphocytes that in complex resembled small granulomas seen in clinical pathology specimens. Acid-fast staining bacteria were observed between and possibly within the cells composing the granulomas. Supernatants from the infected cells collected at 24 and 48 h and 5 and 9 days after infection were analyzed by a multiplexed cytokine bead-based assay using the Luminex 100 and were found to contain interleukin (IL)-6, IL-8, interferon-gamma and tumor necrosis factor-alpha, cytokines known to be involved in human granuloma formation, in quantities from two-fold to 7000-fold higher than supernatants from uninfected control cells. In addition, chemotaxis assays demonstrated that the same supernatants attracted significantly more human peripheral blood mononuclear cells than those of uninfected cells (P<0.001). This model may provide insight into the earliest stages of granuloma formation in those newly infected.     

CD4+ TCR repertoire heterogeneity in Schistosoma mansoni-induced granulomas

The hallmark of Schistosoma mansoni infection is the formation of liver granulomas around deposited ova. The initiation of granuloma formation is T cell-dependent since granulomas are not formed in their absence. We investigated whether a few T cells arrive to initiate the inflammatory lesion and subsequently expand locally, or whether a large repertoire of systemically activated T cells home to the delayed type hypersensitivity reaction induced by the ova. The TCR repertoire of single granulomas from the same liver were analyzed by PCR using Vbeta-specific primers and CDR3 analysis. Each granuloma has a very diverse TCR repertoire indicating that most of the T cells recruited to these lesions are activated systemically. At the same time, sequence analysis of individually sized CDR3 products from single granuloma indicate that a fraction of T cells expand locally at the lesion site. Using TCR transgenic mice containing a pigeon cytochrome c-specific T cell population or lymphocytic choriomeningitis virus infection tracked with lymphocytic choriomeningitis virus-specific tetramers, we demonstrated that nonspecific T cells home to the granuloma if they are activated. However, recombinase-activating gene 2(-/-) pigeon cytochrome c-specific TCR transgenic mice fail to form granulomas in response to S. mansoni ova even after T cell activation, suggesting a requirement for egg-specific T cells in the initiation of these inflammatory lesions. Understanding the mechanism of T cell recruitment into granulomas has important implications for the rational design of immunotherapies for granulomatous diseases.     

Cytokine regulation in experimentally-induced Schistosoma japonicum egg granuloma formation

The formation of granulomas in host tissues in response to trapped Schistosoma japonicum eggs is central to the etiology of schistosomiasis. However, analysis of the host hypersensitivity reactions that result in granuloma formation, in schistosome infection, is not without difficulty. This is due, in part, to the fact that the parasites continuously deposit their eggs as clusters. In order to synchronize host reactions, we established an experimental model of hepatic granuloma formation whereby in vitro laid schistosome eggs are implanted directly into normal and cytokine-deficient mice livers. This model, validated by comparison with an infection model, was used to analyze cytokine regulation of granuloma formation around S. japonicum eggs. Combined models of implantation and cercarial infection were also studied. With special reference to IL-4, IL-13, IFN-γ and IL-18, our in vitro schistosome egg implantation model has shed new light on the roles of cytokines in both the acute and chronic stages of schistosome egg-induced granuloma formation.     

Eosinophils and immune mechanisms. VI. The synergistic combination of granulocyte-macrophage colony-stimulating factor and IL-5 accounts for eosinophil-stimulation promoter activity in Schistosoma mansoni-infected mice

Eosinophil stimulation promoter (ESP) is a lymphokine activity that stimulates eosinophil migration and is produced by mitogen or specific Ag stimulation of spleen cells from mice infected with Schistosoma mansoni. It is also produced by intact, schistosome egg-induced granulomas isolated from the livers of such mice without additional antigenic exposure. The production of ESP activity is decreased during chronic infection in a time course coordinate with granuloma modulation. Characterization of ESP was pursued to determine its relationship to other cytokines and to identify factors that may play a role in granuloma formation and modulation. Chromatographic separations, assays of recombinant cytokines, and cytokine-specific immunodepletions were used in the characterization. ESP+ supernatant fluids contain both granulocyte-macrophage CSF and IL-5. The removal of both granulocyte-macrophage CSF and IL-5 is required to eliminate ESP activity, and together they act synergistically to constitute ESP.     

Neutrophils in Oral Paracoccidioidomycosis and the Involvement of Nrf2

Neutrophils have been implicated in granuloma formation in several infectious diseases, in addition to their main phagocytic and pathogen destruction role. It has been demonstrated that Nrf2 regulates antioxidant protection in neutrophils, attenuating inflammation without compromising the hosts bacterial defense. In this study, we analyzed the presence of neutrophils in Paracoccidioides brasiliensis mycosis (PCM), as well as the immunoexpression of Nrf2. Thirty-nine cases of oral PCM were classified according to quantity of fungi and to the presence of loose or well-organized granulomas and microabscesses. An Nrf2 antibody was used for immunohistochemical analysis. The results showed that neutrophils are present in microabscesses and loose granulomas, but were absent in structured granulomas. A greater quantity of fungi was shown in cases with only loose granulomas when compared to loose and well organized granulomas. Nrf2 was observed in the nuclei of neutrophils of loose granulomas and abscesses, with its expression in loose granulomas maintained despite the additional presence of well organized granulomas in the same specimen. This study suggests that neutrophils participate in P. brasiliensis granuloma formation and that Nrf2 has a possible role in neutrophil survival, via modulation of the inflammatory response.