11ß-hydroxysteroid dehydrogenase type 1 has no effect on survival during experimental malaria but affects parasitemia in a parasite strain-specific manner.

Malaria is a global disease associated with considerable mortality and morbidity. An appropriately balanced immune response is crucial in determining the outcome of malarial infection. The glucocorticoid (GC) metabolising enzyme, 11ß-hydroxysteroid dehydrogenase-1 (11ß-HSD1) converts intrinsically inert GCs into active GCs. 11ß-HSD1 shapes endogenous GC action and is immunomodulatory. We investigated the role of 11ß-HSD1 in two mouse models of malaria. 11ß-HSD1 deficiency did not affect survival after malaria infection, but it increased disease severity and parasitemia in mice infected with Plasmodium chabaudi AS. In contrast, 11ß-HSD1 deficiency rather decreased parasitemia in mice infected with the reticulocyte-restricted parasite Plasmodium berghei NK65 1556Cl1. Malaria-induced antibody production and pathology were unaltered by 11ß-HSD1 deficiency though plasma levels of IL-4, IL-6 and TNF-α were slightly affected by 11ß-HSD1 deficiency, dependent on the infecting parasite. These data suggest that 11ß-HSD1 is not crucial for survival of experimental malaria, but alters its progression in a parasite strain-specific manner.

Association between recent herpes zoster but not herpes simplex infection and subsequent risk of malignancy in women: a retrospective cohort study.

The association between herpes zoster and subsequent cancer risk is still unclear. Consequently, doubts remain regarding the need for investigation of herpes patients for co-existing or subsequent malignancy. This is a retrospective cohort study comparing cancer risk in patients after herpes zoster and age-/sex-matched non-herpes zoster patients, in a primary care-based continuous morbidity database. We tested for interaction by gender, age, diabetes, HRT use or antiviral therapy. Analyses were repeated for patients with and without herpes simplex. The hazard ratio (HR) comparing cancer risk in herpes zoster vs. control patients was significant in all women, women aged > 65 years and subgroups of breast and colorectal cancer (HRs 1·60, 1·82, 2·14, 2·19, respectively). For men, a significant association was found for haematological cancers (HR 2·92). No associations were found with herpes simplex. No interaction was identified with antiviral therapy, diabetes or HRT treatment. We concluded that there was a moderate significant association between herpes zoster and subsequent cancer risk in women aged > 65 years, without any influence of antiviral therapy. No association was found with herpes simplex. There is insufficient reason for extensively testing older patients with herpes zoster or herpes simplex for the presence of occult cancer.

In vitro-selected drug-resistant varicella-zoster virus mutants in the thymidine kinase and DNA polymerase genes yield novel phenotype-genotype associations and highlight differences between antiherpesvirus drugs.

Varicella zoster virus (VZV) is usually associated with mild to moderate illness in immunocompetent patients. However, older age and immune deficiency are the most important risk factors linked with virus reactivation and severe complications. Treatment of VZV infections is based on nucleoside analogues, such as acyclovir (ACV) and its valyl prodrug valacyclovir, penciclovir (PCV) as its prodrug famciclovir, and bromovinyldeoxyuridine (BVDU; brivudin) in some areas. The use of the pyrophosphate analogue foscarnet (PFA) is restricted to ACV-resistant (ACV(r)) VZV infections. Since antiviral drug resistance is an emerging problem, we attempt to describe the contributions of specific mutations in the viral thymidine kinase (TK) gene identified following selection with ACV, BVDU and its derivative BVaraU (sorivudine), and the bicyclic pyrimidine nucleoside analogues (BCNAs), a new class of potent and specific anti-VZV agents. The string of 6 Cs at nucleotides 493 to 498 of the VZV TK gene appeared to function as a hot spot for nucleotide insertions or deletions. Novel amino acid substitutions (G24R and T86A) in VZV TK were also linked to drug resistance. Six mutations were identified in the "palm domain" of VZV DNA polymerase in viruses selected for resistance to PFA, PCV, and the 2-phophonylmethoxyethyl (PME) purine derivatives. The investigation of the contributions of specific mutations in VZV TK or DNA polymerase to antiviral drug resistance and their impacts on the structures of the viral proteins indicated specific patterns of cross-resistance and highlighted important differences, not only between distinct classes of antivirals, but also between ACV and PCV.

On the dual roles and polarized phenotypes of neutrophils in tumor development and progression.

Inconsistencies plague our understanding of the role of neutrophils in cancer and the literature provides evidence for a duality in neutrophil activity on the outcome of cancer. Here, the different effects of neutrophils during the multiple subprocesses of cancer development and progression are overviewed, in order to gain insight into the features of both antitumoral and protumoral tumor-associated neutrophils (TAN). Neutrophils can counteract the progression of malignancies through tumor cytotoxicity, tumor rejection and enhancement of antitumoral immune memory. These cells have recently been phenotypically denominated N1 neutrophils. Recent studies indicate that cytokines, such as TGF-ß and IFN-ß, are involved in directing neutrophil polarization by the tumor microenvironment. With the opposite polarity, N2 neutrophils may be detrimental for the host and beneficial for tumor growth, invasion and metastasis, e.g. through proteolysis of extracellullar matrix components, promotion of angiogenesis and mediation of immunosuppression.

Malaria: host-pathogen interactions, immunopathological complications and therapy.

Malaria is a global tropical disease causing more than 1 million deaths and 300 million clinical cases every year. It is caused by parasites from the genus Plasmodium and is transmitted by Anopheles mosquitoes. Approximately 3 billion people live in malaria-endemic regions and a majority of them are infected. In this review, we discuss the life cycle of the parasite, the complex interactions with the human host and the ensuing immune reactions and complications. The immune system plays a dual role in malaria, by providing life-saving immunity against the parasite, but also by causing often lethal complications in a number of patients. Cytokines, chemokines and proteases are key players in the immunopathological complications, and we propose immunomodulation with dexamethasone as a promising strategy for the therapy of malaria-associated acute respiratory distress syndrome.

Inhibition of enzymatic degradation of adhesive-dentin interfaces.

Adhesive procedures activate dentin-associated matrix metalloproteinases (MMPs), and so iatrogenically initiate bond degradation. We hypothesized that adding MMP inhibitors to adhesive primers may prevent this endogenous enzymatic degradation, thereby improving bond durability. A non-specific MMP inhibitor (chlorhexidine) and a MMP-2/9-specific inhibitor (SB-3CT) were admixed to the primers of an etch & rinse and a self-etch adhesive, both considered as gold-standard adhesives within their respective categories. For dentin powder exposed to the adhesives under clinical application conditions, gelatin zymography revealed the release of MMP-2 (not of MMP-9) by the etch & rinse adhesive, while no release of enzymes could be detected for the mild self-etch adhesive, most likely because of its limited dentin demineralization effect. The built-in MMP inhibitors appeared effective in reducing bond degradation only for the etch & rinse adhesive, and not for the self-etch adhesive. Water sorption of adhesive interfaces most likely remains the principal mechanism of bond degradation, while endogenous enzymes appear to contribute to bond degradation of only etch & rinse adhesives.

Interphotoreceptor retinoid-binding protein as biomarker in systemic autoimmunity with eye inflictions.

Autoimmune diseases of the eye, exemplified by Beh cet disease and Vogt-Koyanagi-Harada disease, are a major cause of blindness. We studied interphotoreceptor retinoid-binding protein (IRBP), a dominant autoimmune antigen in the eye. Aqueous humour samples from 28 patients with active uveitis were analysed for immunoglobulin G (IgG) content as a marker for blood-ocular barrier breakdown and by gelatinase B zymography for the detection of inflammation. The data were correlated with the presence of intact IRBP (approximately 140 kD) as determined by Western blot analysis and with the clinical disease activity. Aqueous humour samples from control eyes and eyes with low disease activity showed positive immunoreactivity for intact IRBP. The IRBP signal weakened or disappeared with higher disease activity. Significant positive correlations were observed between disease activity and levels of gelatinase B/matrix metalloproteinase-9 (MMP-9) (rs=0.713; P<0.001) and IgG (rs=0.580; P=0.001). Significant negative correlations were found between levels of IRBP and disease activity (rs=-0.520; P=0.005) and levels of MMP-9 (rs=-0.727; P<0.001) and of IgG (rs=-0.834; P<0.001). Whereas neutrophil elastase converted intact IRBP into an immunoreactive 55 kD peptide in vitro, the conversion by neutrophil degranulates resembled more the in vivo context with a complete degradation of IRBP. Reversal of inflammation with immunosuppressive therapy was accompanied with reappearance of intact IRBP and disappearance of IgG and MMP-9. The analysis of IRBP proteolysis is useful as a biomarker for uveitis and suggests that inhibition of proteinases might become a therapeutic strategy in an inflammatory context of a damaged blood-ocular barrier.

Matrix metalloproteinase-9/gelatinase B is a putative therapeutic target of chronic obstructive pulmonary disease and multiple sclerosis.

Matrix metalloproteinases (MMPs) are a large family of proteolytic enzymes involved in an array of physiological and pathological processes from development, morphogenesis, reproduction, wound healing, and aging to inflammation, angiogenesis, neurological disorders, and cancer cell invasion and metastasis. The imbalance between MMP activity and the inhibitory action of tissue inhibitors of metalloproteinases (TIMPs) are implicated in multiple diseases. Secreted in the body in a latent form, upon activation MMP-9 (gelatinase B) acts on many inflammatory substrates, and thus is suspected of contributing to the progression of cardiovascular disease, rheumatoid arthritis, and the subjects of this review, chronic obstructive pulmonary disease (COPD) and multiple sclerosis (MS). COPD is the fourth most common cause of death in the United States. In COPD, increased expression of MMP-9 by inflammatory cells e.g. neutrophils and macrophages is correlated with a variety of processes that cause lung damage. MMP-9 is also important in cytokine and protease modulation; it degrades the serine protease inhibitor alpha(1)-antitrypsin, which thus may lead to lung destruction. MS affects approximately 400,000 Americans and over a million people worldwide. Upregulation of MMP-9 increases the permeability of the blood brain barrier (BBB), facilitates the infiltration of leukocytes into the central nervous system, and causes myelin sheath degradation and neuronal damage. Early stage clinical trials have shown promising results when MMP-9 is inhibited in MS. These observations lead to the hypothesis that MMP-9 is a potential drug target for both COPD and MS and further development of highly potent and specific MMP-9 inhibitors is warranted.

Triggering of T-cell leukemia and dissemination of T-cell lymphoma in MMP-9-deficient mice.

Previous studies have shown that high levels of MMP-9 can be detected in the serum of patients with various lymphoid malignancies and in leukemia/lymphoma culture supernatants. Indeed, aggressive forms of lymphoma constitutively produce MMP-9 and its elevated levels in the serum or in tissues correlate with advanced stage and poor patient survival. In vitro, MMP-9, which is also produced by the host peritumoral cells in response to the presence of tumors, plays an important role in migration of tumor cells through artificial basement membranes or endothelial cells. In this study, using MMP-9-deficient mice, we show that absence of MMP-9 does not prevent the development of primary T-cell leukemia. Furthermore, MMP-9-deficient cell lines retained their tumorigenic potential, as shown by their ability to induce thymic lymphoma in young syngeneic wild-type animals. In addition, these MMP-9-deficient tumor cells disseminate in normal mice, or mice that are deficient for MMP-9, indicating that tumor growth and dissemination can occur in total absence of MMP-9. These results show for the first time than lymphoma growth can occur in total absence of MMP-9 and have consequences for therapy of invasive cancers with inhibitors of MMPs.

Dual infection with polyomavirus BK and acyclovir-resistant herpes simplex virus successfully treated with cidofovir in a bone marrow transplant recipient.

A hematopoietic stem cell transplant recipient developed a mucosal herpes simplex virus-1 (HSV-1) infection while under acyclovir (ACV) treatment (HSV was later shown to be resistant to ACV). Concomitantly, the patient presented a hemorrhagic cystitis (HC) due to polyomavirus BK, for which intravenous cidofovir (CDV) was prescribed. The patient benefited from the broad-spectrum anti-DNA virus activity of CDV, and not only the HC resolved without signs of nephrotoxicity but also the HSV-1 lesions disappeared. This is the first report describing the effect of CDV on 2 simultaneous and unrelated DNA viral infections in an immunosuppressed transplant recipient. In addition, we describe here that this HSV-1 isolate possesses a unique phenotype and genotype.

Expression of chemokines and gelatinase B in sympathetic ophthalmia.

PURPOSE: To examine the expression of gelatinase B (matrix metalloproteinase-9) and the chemokines monocyte chemotactic protein-1 (CCL2/MCP-1) and stromal cell-derived factor-1 (CXCL12/SDF-1) in sympathetic ophthalmia (SO). METHODS: Five enucleated exciting eyes with a clinical diagnosis and typical histopathological findings of SO were studied by immunohistochemical techniques using a panel of monoclonal antibodies directed against gelatinase B, MCP-1, and SDF-1. In addition, a panel of monoclonal and polyclonal antibodies was used to characterize the composition of the inflammatory infiltrate. RESULTS: In all cases, the extensive uveal inflammatory infiltrate was organized as a diffuse infiltrate and as large granulomas consisting of epithelioid cells and multinucleated giant cells. CD20(+) B lymphocytes predominated in the diffuse infiltrate and CD3(+) T lymphocytes were few. The monocyte/macrophage marker CD68 was expressed in scattered inflammatory mononuclear cells and within granulomas and Dalen-Fuchs nodules. Most of the inflammatory cells were HLA-DR(+). Immunoreactivity for gelatinase B, MCP-1, and SDF-1 was observed in cells within granulomas and in scattered epithelioid cells. Immunoreactivity for MCP-1 was noted in retinal pigment epithelial cells. Endothelial cells of choriocapillaries showed weak immunoreactivity for SDF-1. CONCLUSIONS: Gelatinase B, MCP-1, and SDF-1 might have a pathogenic role in the recruitment of leucocytes into the eye in SO.

PECAM-1 and gelatinase B coexist in vascular cuffs of multiple sclerosis lesions.

In multiple sclerosis (MS), the matrix metalloprotease (MMP) gelatinase B/MMP-9 and platelet endothelial cell adhesion molecule (PECAM)-1 have both been implicated in trans-endothelial infiltration of leucocytes into the brain, but their functional connection has not yet been investigated. We investigated the expression of gelatinase B and PECAM-1 in post mortem brains of MS patients by immunohistochemistry. Because increased soluble PECAM-1 serum levels have been observed in MS patients, we also tested in vitro whether this could be due to cleavage of PECAM-1 by gelatinase B or matrilysin-1/MMP-7. Constitutive expression of PECAM-1 was found on brain endothelial cells, whilst in active MS lesions cell-bound PECAM-1 was highly up-regulated on foamy macrophages in perivascular infiltrates and co-localized with gelatinase B. However, human THP-1 monocyte-bound or soluble recombinant PECAM-1 were both resistant to proteolytic cleavage by gelatinase B or matrilysin-1 in vitro, as demonstrated by Western blot analysis and flow cytometry. These results suggest that PECAM-1 and gelatinase B may complement each other during the transmigration of the blood-brain barrier by mononuclear cells.

Generation of glycosylated remnant epitopes from human collagen type II by gelatinase B.

Gelatinase B/matrix metalloproteinase-9 (MMP-9) is an inflammatory mediator and effector. Considerable amounts of gelatinase B are released by neutrophils in the synovial cavity of patients with rheumatoid arthritis, and gelatinase B-deficient mice are resistant against antibody-induced arthritis. Native human collagen type II is susceptible to cleavage by various collagenases (MMP-1, MMP-8, and MMP-13), which cleave at a single position in the triple helix. Although the triple-helical structure may persist after this single cleavage, we show that gelatinase B degrades the resulting fragments into small remnant peptides. These were identified by mass spectrometry and Edman degradation. Localization of 31 cleavage sites shows that the immunodominant epitopes remain intact after cleavage and may become available, processed as antigens and presented in MHC-II molecules. Furthermore, most post-translational modifications were identified on the fragments, including nine glycosylation sites. In particular, it is shown for the first time by structural analysis that in natural human collagen II, lysines in the main immunodominant epitope are modified by partial hydroxylation and partial glycosylation. Determination of T-cell reactivity against such fragments indicates that, besides the two known main immunodominant epitopes, other glyco-epitopes may be present in collagen II. This reinforces the role of glycopeptide antigens in autoimmunity.

Gelatinase B, PECAM-1 and MCP-3 gene polymorphisms in Belgian multiple sclerosis.

Polymorphic microsatellite markers in the genes for gelatinase B, PECAM-1 and MCP-3 have previously been analysed in Swedish and Sardinian individuals to test for association with multiple sclerosis (MS). Confirmation and comparison of genetic associations in various ethnic populations is mandatory and, therefore, we studied these three gene polymorphisms in 216 clinically definite MS patients and 193 normal controls, and in 148 simplex MS families, all of Belgian origin. No allelic associations were found between MS and the CA microsatellite marker in the promoter region of the gelatinase B gene, and the polymorphic CA repeat in the sixth intron of PECAM1. However, the two most abundant alleles of the CA/GA microsatellite polymorphism in the promoter-enhancer region of the MCP-3 gene, A2 (109 bp) and A3 (111 bp), were found to be significantly associated with disease in the case-control study [OR (95% CI)=0.68 (0.51-0.92), p (1 df)=0.015 and OR (95% CI)=1.62 (1.22-2.14), p (1 df)=0.0010, respectively], but not in the family study. These results are in agreement with previous findings in the Swedish and Sardinian populations and reinforce the possibility of a role for chemokines in MS pathogenesis.

Chemokines and proteinases in autoimmune diseases and cancer.

Chemotactic cytokines or chemokines form a family of proinflammatory proteins that are functionally linked to various classes of proteases, including matrix metalloproteinases (MMPs). Both families of molecules are key players in the migration of inflammatory cells in autoimmune diseases and in invasive cancers. For example, the chemokine interleukin-8 acts as a fast secretagogue of gelatinase B in granulocytes and is increased in the synovial fluid of arthritis patients and may locally recruit and activate neutrophils. The latter are the most abundant inflammatory cell type in the joints of patients with rheumatoid arthritis. In the case of the inflamed joint, the contribution of matrix remodeling enzymes in the breakdown of cartilage and bone is trivial. Gelatinase B (MMP-9) was documented in autoimmune diseases and cancer by immunohistochemistry with the use of monoclonal antibodies. Studies in rheumatoid arthritis and multiple sclerosis led us to postulate the "Remnant Epitopes Generate Autoimmunity" or REGA model for autoimmunity. This model is based on the pathophysiological role of three major classes of molecules involved in aspecific primary immune defense mechanisms: the cytokines, the chemokines and the proteases. The REGA model has proven to be useful for the development of disease treatment strategies. Particular cytokines are disease-limiting and may thus be used for the treatment of autoimmune disorders. Cytokines and chemokines that induce enzymes promote disease and may be antagonized. Along this line of research, we have recently identified natural and biosynthetic chemokine antagonists. Some of these have shown potent antiviral activity against human immunodeficiency virus. It is expected that these might also become useful in the treatment of autoimmune diseases and invasive cancers. A similar effect may be expected by the antagonization of damaging proteases or with the use of recombinant or synthetic enzyme inhibitors.

Neutrophil gelatinase B and chemokines in leukocytosis and stem cell mobilization.

Leukocytosis is a physiopathological mechanism primarily to combat infections, whereas stem cell mobilization is induced for therapeutical purposes. Both processes are dependent on the balance between leukocyte and stem cell retention and mobilization. The retention is mediated by the specific architecture of the bone marrow, adhesion molecules and the production of chemokines in the bone marrow, which attract escaped immature cells to the marrow. Mobilization is the effect of the action of "peripheral" chemokines, such as interleukin-8 (IL-8 or CXCL8) and the remodeling of the matrix and basement membranes by matrix enzymes, such as gelatinase B (MMP-9). Recent studies lead to the conclusion that neutrophils, IL-8/CXCL8 and gelatinase B/MMP-9 play control roles in leukocytosis and stem cell mobilization. Neutrophils are the predominant circulating leukocyte type and IL-8/CXCL8 is the major neutrophil chemoattractant in humans. Gelatinase B and no gelatinase A is rapidly released from prestored granules after activation of neutrophils by IL-8/CXCL8. Moreover, neutrophils do not produce TIMP-1 and can chemically activate latent progelatinase B. Activated gelatinase B catalyses the aminoterminal truncation of IL-8/CXCL8 into a tenfold more potent chemokine. This implies that, when IL-8/CXCL8 appears in the circulation, the bone marrow is instructed to release neutrophils and concomitantly stem cells. These studies suggest that IL-8/CXCL8 and gelatinase B/MMP-9 are targets for the modulation of stem cell mobilization.

Selective induction of CCL18/PARC by staphylococcal enterotoxins in mononuclear cells and enhanced levels in septic and rheumatoid arthritis.

Chemokines are mediators of innate and acquired immunity. CCL18, also designated pulmonary and activation-regulated chemokine (PARC), dendritic cell-derived CC chemokine-1 (DC-CK1), alternative macrophage activation-associated CC chemokine-1 (AMAC-1) and macrophage inflammatory protein-4 (MIP-4), was for the first time isolated from peripheral blood mononuclear cells (PBMC) and biochemically characterized. We found that CCL18/PARC protein is spontaneously secreted by PBMC and is selectively induced in PBMC by staphylococcal enterotoxins (SEA, SEB) and IL-4, but not by IFN-gamma and the CXCL8/IL-8 inducers lipopolysaccharide (LPS) or Concanavalin A. Human fibroblasts, chondrocytes and endothelial cells did not produce CCL18/PARC in response to inflammatory mediators such as measles virus, double-stranded RNA, LPS or IL-1beta, whereas up to 150 ng/ml of CCL2/MCP-1 was induced under these conditions. In synovial fluids from septic and rheumatoid arthritis patients, fourfold-enhanced CCL18/PARC levels (150 ng/ml) were detected compared to those in crystal-induced arthritis and osteoarthritis. In septic arthritis, the synovial levels of CCL18/PARC were fivefold higher than those of CXCL8/IL-8. Immunochemistry revealed CD68(+) monocytes/macrophages as the main CCL18/PARC-producing cell type in both PBMC and arthritic synovial tissue. In addition, CD1a(+) blood dendritic cells expressed CCL18/PARC. These findings suggest that monocytic cells respond to Gram-positive bacterial infection by the production of CCL18/PARC in the synovial cavity.

Amino-terminal truncation of CXCR3 agonists impairs receptor signaling and lymphocyte chemotaxis, while preserving antiangiogenic properties.

The interferon (IFN)-inducible chemokines, specifically, IFN-gamma-inducible protein-10 (IP-10), monokine induced by IFN-gamma (Mig), and IFN-inducible T-cell alpha-chemoattractant (I-TAC), share a unique CXC chemokine receptor (CXCR3). Recently, the highly specific membrane-bound protease and lymphocyte surface marker CD26/dipeptidyl peptidase IV (DPP IV) was found to be responsible for posttranslational processing of chemokines. Removal of NH(2)-terminal dipeptides by CD26/DPP IV alters chemokine receptor binding and signaling, and hence inflammatory and anti-human immunodeficiency virus (HIV) activities. CD26/DPP IV and CXCR3 are both markers for Th1 lymphocytes and, moreover, CD26/DPP IV is present in a soluble, active form in human plasma. This study reports that at physiologic enzyme concentrations CD26/DPP IV cleaved 50% of I-TAC within 2 minutes, whereas for IP-10 and Mig the kinetics were 3- and 10-fold slower, respectively. Processing of IP-10 and I-TAC by CD26/DPP IV resulted in reduced CXCR3-binding properties, loss of calcium-signaling capacity through CXCR3, and more than 10-fold reduced chemotactic potency. Moreover, IP-10 and I-TAC cleaved by CD26/DPP IV acted as chemotaxis antagonists and CD26/DPP IV-truncated IP-10 and Mig retained their ability to inhibit the angiogenic activity of interleukin-8 in the rabbit cornea micropocket model. These data demonstrate a negative feedback regulation by CD26/DPP IV in CXCR3-mediated chemotaxis without affecting the angiostatic potential of the CXCR3 ligands IP-10 and Mig.

Matrix remodelling enzymes, the protease cascade and glycosylation.

Glycosylation influences the specific activities of serine proteases including tissue-type plasminogen activator and plasmin which act together in a ternary complex with fibrin. Serine proteases and matrix metalloproteinases (MMPs), including gelatinase B, participate in a protease cascade to remodel the extracellular matrix. In addition to the recognition and targeting functions of carbohydrates and the fact that they confer protease resistance on glycoproteins, oligosaccharides may extend particular protein domains of matrix remodelling enzymes and fine-control their activities within the context of the extracellular matrix. For example, the sialic acids of gelatinase B influence the catalytic activity of this enzyme in a complex with the tissue inhibitor of metalloproteinases-1 (TIMP-1).