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Walz A, Lehmann U, Duthaler U, Mäser P, Wittlin S. In vivo antimalarial efficacy of Artemisia afra powder suspensions. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2024; 129:155644. [PMID: 38761524 DOI: 10.1016/j.phymed.2024.155644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 04/02/2024] [Accepted: 04/13/2024] [Indexed: 05/20/2024]
Abstract
BACKGROUND A global death toll of 608,000 in 2022 and emerging parasite resistance to artemisinin, the mainstay of antimalarial chemotherapy derived from the Chinese herb Artemisia annua, urge the development of novel antimalarials. A clinical trial has found high antimalarial potency for aqueous extracts of A. annua as well as its African counterpart Artemisia afra, which contains only trace amounts of artemisinin. The artemisinin-independent antimalarial activity of A. afra points to the existence of other antimalarials present in the plant. However, the publication was retracted due to ethical and methodological concerns in the trial, so the only evidence for antimalarial activity of A. afra is built on in vitro studies reporting efficacy only in the microgram per milliliter range. HYPOTHESIS Our study aims to shed more light on the controversy around the antimalarial activity of A. afra by assessing its efficacy in mice. In particular, we are testing the hypothesis that A. afra contains a pro-drug that is inactive in vitro but active in vivo after metabolization by the mammalian host. METHODS Plasmodium berghei-infected mice were treated once or thrice (on three consecutive days) with various doses of A. afra, A. annua, or pure artemisinin. RESULTS Aqueous powder suspensions of A. annua but not A. afra showed antimalarial activity in mice. CONCLUSION Our experiments conducted in mice do not support the pro-drug hypothesis.
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Hellingman A, Sifoniou K, Buser T, Thommen BT, Walz A, Passecker A, Collins J, Hupfeld M, Wittlin S, Witmer K, Brancucci NMB. Next Generation Chemiluminescent Probes for Antimalarial Drug Discovery. ACS Infect Dis 2024; 10:1286-1297. [PMID: 38556981 PMCID: PMC11019541 DOI: 10.1021/acsinfecdis.3c00707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 03/07/2024] [Accepted: 03/13/2024] [Indexed: 04/04/2024]
Abstract
Malaria is caused by parasites of the Plasmodium genus and remains one of the most pressing human health problems. The spread of parasites resistant to or partially resistant to single or multiple drugs, including frontline antimalarial artemisinin and its derivatives, poses a serious threat to current and future malaria control efforts. In vitro drug assays are important for identifying new antimalarial compounds and monitoring drug resistance. Due to its robustness and ease of use, the [3H]-hypoxanthine incorporation assay is still considered a gold standard and is widely applied, despite limited sensitivity and the dependence on radioactive material. Here, we present a first-of-its-kind chemiluminescence-based antimalarial drug screening assay. The effect of compounds on P. falciparum is monitored by using a dioxetane-based substrate (AquaSpark β-D-galactoside) that emits high-intensity luminescence upon removal of a protective group (β-D-galactoside) by a transgenic β-galactosidase reporter enzyme. This biosensor enables highly sensitive, robust, and cost-effective detection of asexual, intraerythrocytic P. falciparum parasites without the need for parasite enrichment, washing, or purification steps. We are convinced that the ultralow detection limit of less than 100 parasites of the presented biosensor system will become instrumental in malaria research, including but not limited to drug screening.
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Walz A, Duffey M, Aljayyoussi G, Sax S, Leroy D, Besson D, Burrows JN, Cherkaoui-Rbati MH, Gobeau N, Westwood MA, Siethoff C, Gamo FJ, Mäser P, Wittlin S. The Parasite Reduction Ratio (PRR) Assay Version 2: Standardized Assessment of Plasmodium falciparum Viability after Antimalarial Treatment In Vitro. Pharmaceuticals (Basel) 2023; 16:ph16020163. [PMID: 37009844 PMCID: PMC9959027 DOI: 10.3390/ph16020163] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 01/12/2023] [Accepted: 01/14/2023] [Indexed: 01/24/2023] Open
Abstract
With artemisinin-resistant Plasmodium falciparum parasites emerging in Africa, the need for new antimalarial chemotypes is persistently high. The ideal pharmacodynamic parameters of a candidate drug are a rapid onset of action and a fast rate of parasite killing or clearance. To determine these parameters, it is essential to discriminate viable from nonviable parasites, which is complicated by the fact that viable parasites can be metabolically inactive, whilst dying parasites can still be metabolically active and morphologically unaffected. Standard growth inhibition assays, read out via microscopy or [3H] hypoxanthine incorporation, cannot reliably discriminate between viable and nonviable parasites. Conversely, the in vitro parasite reduction ratio (PRR) assay is able to measure viable parasites with high sensitivity. It provides valuable pharmacodynamic parameters, such as PRR, 99.9% parasite clearance time (PCT99.9%) and lag phase. Here we report the development of the PRR assay version 2 (V2), which comes with a shorter assay duration, optimized quality controls and an objective, automated analysis pipeline that systematically estimates PRR, PCT99.9% and lag time and returns meaningful secondary parameters such as the maximal killing rate of a drug (Emax) at the assayed concentration. These parameters can be fed directly into pharmacokinetic/pharmacodynamic models, hence aiding and standardizing lead selection, optimization, and dose prediction.
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Walz A, Leroy D, Andenmatten N, Mäser P, Wittlin S. Anti-malarial ozonides OZ439 and OZ609 tested at clinically relevant compound exposure parameters in a novel ring-stage survival assay. Malar J 2019; 18:427. [PMID: 31849323 PMCID: PMC6918666 DOI: 10.1186/s12936-019-3056-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 12/07/2019] [Indexed: 11/20/2022] Open
Abstract
Background Drug efficacy against kelch 13 mutant malaria parasites can be determined in vitro with the ring-stage survival assay (RSA). The conventional assay protocol reflects the exposure profile of dihydroartemisinin. Methods Taking into account that other anti-malarial peroxides, such as the synthetic ozonides OZ439 (artefenomel) and OZ609, have different pharmacokinetics, the RSA was adjusted to the concentration–time profile of these ozonides in humans and a novel, semi-automated readout was introduced. Results When tested at clinically relevant parameters, it was shown that OZ439 and OZ609 are active against the Plasmodium falciparum clinical isolate Cam3.IR539T. Conclusion If the in vitro RSA does indeed predict the potency of compounds against parasites with increased tolerance to artemisinin and its derivatives, then the herein presented data suggest that following drug-pulses of at least 48 h, OZ439 and OZ609 will be highly potent against kelch 13 mutant isolates, such as P. falciparum Cam3.IR539T.
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Jourdan J, Walz A, Matile H, Schmidt A, Wu J, Wang X, Dong Y, Vennerstrom JL, Schmidt RS, Wittlin S, Mäser P. Stochastic Protein Alkylation by Antimalarial Peroxides. ACS Infect Dis 2019; 5:2067-2075. [PMID: 31626733 DOI: 10.1021/acsinfecdis.9b00264] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Antimalarial peroxides such as the phytochemical artemisinin or the synthetic ozonides arterolane and artefenomel undergo reductive cleavage of the pharmacophoric peroxide bond by ferrous heme, released by parasite hemoglobin digestion. The generated carbon-centered radicals alkylate heme in an intramolecular reaction and proteins in an intermolecular reaction. Here, we determine the proteinaceous alkylation signatures of artemisinin and synthetic ozonides in Plasmodium falciparum using alkyne click chemistry probes to identify target proteins by affinity purification and mass spectrometry-based proteomics. Using stringent controls and purification procedures, we identified 25 P. falciparum proteins that were alkylated by the antimalarial peroxides in a peroxide-dependent manner, but the alkylation patterns were more random than we had anticipated. Moreover, there was little overlap in the alkylation signatures identified in this work and those disclosed in previous studies. Our findings suggest that alkylation of parasite proteins by antimalarial peroxides is likely to be a nonspecific, stochastic process.
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Hatz C, Walz A, Genton B, Behrens R. [True and virtual risks of travellers]. REVUE MEDICALE SUISSE 2014; 10:1001-1003. [PMID: 24908743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Evidence-based information on travel associated mortality is scarce. Perception, intuition and the availability of interventions such as vaccinations and chemoprophylaxis often guide pre-travel advice. Important risks including accidents and cardiovascular events are not routinely included in pre-travel consultations although they cause more fatalities and costs than infectious diseases. The increased risk of sustaining a road accident in poor economy countries should always be mentioned. The general practitioner is further best placed to discuss possible problems of travellers with chronic diseases before travel.
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Leijen S, Middleton MR, Tresca P, Kraeber-Bodere F, Dieras V, Scheulen ME, Tessier J, Xu ZX, Shochat E, Walz A, Deutsch J, Blotner S, Lopez Valverde V, Naegelen VM, Schellens JHM, Eberhardt WE. Phase I (Ph) safety, pharmacodynamic (PD), and pharmacokinetic (PK) trial of a pure MEK inhibitor (i), RO4987655, in patients with advanced /metastatic solid tumor. J Clin Oncol 2011. [DOI: 10.1200/jco.2011.29.15_suppl.3017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Freitas S, Walz A, Merkle HP, Gander B. Solvent extraction employing a static micromixer: A simple, robust and versatile technology for the microencapsulation of proteins. J Microencapsul 2010. [DOI: 10.3109/02652040309178050] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Pietrowski D, Walz A, Becker J, Sator M. Das Corpus luteum – ein zelluläres Modellsystem. Geburtshilfe Frauenheilkd 2009. [DOI: 10.1055/s-0029-1225113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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Walz A, Haberland B, Wollenberg B, Bausewein C. [Chronic pain therapy for patients with head and neck tumors]. HNO 2006; 54:803-16; quiz 817-8. [PMID: 16841225 DOI: 10.1007/s00106-006-1441-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Patients with tumors of the head and neck region commonly suffer from chronic pain, which is often treated insufficiently. Pain management according to the WHO analgesic ladder can effectively reduce pain in most patients. For head and neck cancer, specific aspects of tumor localization and psychosocial factors must be taken into consideration.
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Seidel C, Walz A, Park S, Cohen JD, Ludwig-Müller J. Indole-3-acetic acid protein conjugates: novel players in auxin homeostasis. PLANT BIOLOGY (STUTTGART, GERMANY) 2006; 8:340-5. [PMID: 16807826 DOI: 10.1055/s-2006-923802] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Indole-3-acetic acid (IAA) is found in plants in both free and conjugated forms. Within the group of conjugated IAA there is a unique class of proteins and peptides where IAA is attached directly to the polypeptide structure as a prosthetic group. The first gene, IAP1, encoding for a protein with IAA as a prosthetic group, was cloned from bean (Phaseolus vulgaris). It was shown that the expression of IAP1 as a major IAA modified protein in bean seed (PvIAP1) was correlated to a developmental period of rapid growth during seed development. Moreover, this protein underwent rapid degradation during germination. Since further molecular analysis was difficult in bean, the IAP1 gene was transformed into Arabidopsis thaliana and Medicago truncatula. Expression of the bean IAP1 gene in both plant species under the control of its native promoter targeted protein expression to the seeds. In Arabidopsis no IAA was found to be attached to PvIAP1. These results show that there is specificity to protein modification by IAA and suggests that protein conjugation may be catalyzed by species specific enzymes. Furthermore, subcellular localization showed that in Arabidopsis PvIAP1 was predominantly associated with the microsomal fraction. In addition, a related protein and several smaller peptides that are conjugated to IAA were identified in Arabidopsis. Further research on this novel class of proteins from Arabidopsis will both advance our knowledge of IAA proteins and explore aspects of auxin homeostasis that were not fully revealed by studies of free IAA and lower molecular weight conjugates.
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Walz A, Keck C, Weber H, Kissel C, Pietrowski D. Effects of luteinizing hormone and human chorionic gonadotropin on corpus luteum cells in a spheroid cell culture system. Mol Reprod Dev 2005; 72:98-104. [PMID: 15948162 DOI: 10.1002/mrd.20325] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The human corpus luteum (CL) is a highly vascularized, temporarily active endocrine gland and consists mainly of granulosa cells (GCs), theca cells (TCs), and endothelial cells (ECs). Its cyclic growth and development takes place under the influence of gonadotropic hormones. If pregnancy does occur, human chorionic gonadotropin (hCG) takes over the function of luteinizing hormone (LH) and, in contrast to LH, extends the functional life span of the CL. In this study, we investigated the effects of hCG and LH in a spheroidal cell culture model of CL development. Our data indicate that GCs secrete factors under the control of hCG that increase sprout formation of EC-spheroids. We demonstrate that the most prominent of these factors is VEGF-A. Furthermore, we found that both LH and hCG decrease sprout formation of GC-spheroids. After forming EC-GC coculture spheroids and consequently bringing GCs and ECs in close contact, sprouting increased under the influence of hCG, however not under LH. These experiments provide evidence for an hCG dependent functional switch in the GCs after coming in contact with ECs. Moreover, it demonstrates the considerably different effects of hCG and LH on GCs although their signaling is transmitted via the same receptor.
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Wollenberg B, Walz A, Kolbow K, Pauli C, Chaubal S, Andratschke M. Clinical relevance of circulating tumour cells in the bone marrow of patients with SCCHN. Oncol Res Treat 2004; 27:358-62. [PMID: 15347890 DOI: 10.1159/000079088] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
BACKGROUND Clinical outcome of patients with head and neck squamous cell carcinoma (SCCHN) depends on several risk factors like the presence of locoregional lymph node or distant metastases, stage, localisation and histologic differentiation of the tumour. Circulating tumour cells in the bone marrow indicate a poor prognosis for patients with various kinds of malignoma. The present study examines the clinical relevance of occult tumour cells in patients suffering from SCCHN. PATIENTS AND METHODS Bone marrow aspirates of 176 patients suffering from SCCHN were obtained prior to surgery and stained for the presence of disseminated tumour cells. Antibodies for cytokeratin 19 were used for immunohistochemical detection with APAAP on cytospin slides. Within a clinical follow-up protocol over a period of 60 months, the prognostic relevance of several clinicopathological parameters and occult tumour cells was evaluated. RESULTS Single CK19-expressing tumour cells could be detected in the bone marrow of 30.7% of the patients. There is a significant correlation between occult tumour cells in the bone marrow and relapse. Uni- and multivariate analysis of all clinical data showed the metastases in the locoregional lymph system and detection of disseminated tumour cells in the bone marrow to be statistically highly significant for clinical prognosis. CONCLUSION The detection of minimal residual disease underlines the understanding of SCCHN as a systemic disease. Further examination of such cells will lead to a better understanding of the tumour biology, as well as to improvement of diagnostic and therapeutic strategies.
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Walz A, Bausewein C, Kuprella T, Wollenberg B. Palliativmedizinische Betreuung von Patienten mit Kopf-Hals-Tumoren. Laryngorhinootologie 2004. [DOI: 10.1055/s-2004-823532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Pietrowski D, Walz A, Herr D, Keck C. Human granulosa cells secretes angiogenic growth factors under control of chorion gonadotropin. Exp Clin Endocrinol Diabetes 2004. [DOI: 10.1055/s-2004-819277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Keck C, Walz A, Phan GAB, Pietrowski D. HCG-abhängig exprimierte Wachstumsfaktoren in Granulosazellen modulieren die Proliferation und Sprossung von Endothelzellen. Geburtshilfe Frauenheilkd 2003. [DOI: 10.1055/s-2003-815130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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Freitas S, Walz A, Merkle HP, Gander B. Solvent extraction employing a static micromixer: a simple, robust and versatile technology for the microencapsulation of proteins. J Microencapsul 2003; 20:67-85. [PMID: 12519703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
The potential of a static micromixer for the production of protein-loaded biodegradable polymeric microspheres by a modified solvent extraction process was examined. The mixer consists of an array of microchannels and features a simple set-up, consumes only very small space, lacks moving parts and offers simple control of the microsphere size. Scale-up from lab bench to industrial production is easily feasible through parallel installation of a sufficient number of micromixers ('number-up'). Poly(lactic-co-glycolic acid) microspheres loaded with a model protein, bovine serum albumin (BSA), were prepared. The influence of various process and formulation parameters on the characteristics of the microspheres was examined with special focus on particle size distribution. Microspheres with monomodal size distributions having mean diameters of 5-30 micro m were produced with excellent reproducibility. Particle size distributions were largely unaffected by polymer solution concentration, polymer type and nominal BSA load, but depended on the polymer solvent. Moreover, particle mean diameters could be varied in a considerable range by modulating the flow rates of the mixed fluids. BSA encapsulation efficiencies were mostly in the region of 75-85% and product yields ranged from 90-100%. Because of its simple set-up and its suitability for continuous production, static micromixing is suggested for the automated and aseptic production of protein-loaded microspheres.
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Walz A. [Not Available]. WURZBURGER MEDIZINHISTORISCHE MITTEILUNGEN 2001; 18:55-63. [PMID: 11624401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
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Zeidler R, Mayer A, Gires O, Schmitt B, Mack B, Lindhofer H, Wollenberg B, Walz A. TNFalpha contributes to the antitumor activity of a bispecific, trifunctional antibody. Anticancer Res 2001; 21:3499-503. [PMID: 11848515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
Immunological cancer therapies focus on the activation of immune effector cells yielding a specific antitumor activity. Disseminated tumor cells are regarded as the origin of metastases and consequently their elimination is the central objective of adjuvant immune therapies. The use of bispecific antibodies is an approach that is regarded as promising in order to fight those disseminated tumor cells. Unfortunately, the efficiency of these antibodies is limited by the fact that they usually activate a single class of effector cell, thus not yielding optimal immune response. In addition, tumor cells may down-regulate the antibody's target molecule and escape recognition. We have recently described results with an intact bispecific molecule, BiUII, that represents a new class of intact antibodies. These antibodies, termed "triomab", provide an excellent antitumor activity in vitro, a fact that most probably is attributable to the simultaneous activation of different classes of immune effector cells. We have now investigated this antitumor activity in more detail and demonstrate here that at least a dual mechanism accounts for triomab-mediated killing of tumor cells: besides direct cell-mediated killing, triomab induces the production of TNFalpha in PBMCs at concentrations that induce apoptosis in target cells. This bystander effect may be of special interest for the clinical application of triomab in terms of killing of target antigen-negative tumor cells.
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Baggiolini M, Dewald B, Walz A. [Alternative methods to animal experimentation lead to the discovery of a novel inflammation factor]. ALTEX 2001; 6:4-11. [PMID: 11208271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
Simple testing models have been developed for the evaluation of chemical or biological compounds that influence the activity of leukocytes. Human blood neutrophil leukocytes are used. They are stimulated in various ways, and the effects of test compounds on the release of enzymes, the generation of oxygen radicals and cell damage are quantified. All assays are performed in microtiter plates and the responses are evaluated by multi-well photometry or fluorimetry. The models are apt to detect compounds acting on leukocytes as stimuli, inhibitors, and response modifiers. The use of these methods led to the discovery of a novel inflammatory peptide, NAP-1, which activates neutrophil leukocytes. NAP-1 consists of 72 amino acids and is generated by a variety of tissue cells.
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Rieder G, Einsiedl W, Hatz RA, Stolte M, Enders GA, Walz A. Comparison of CXC chemokines ENA-78 and interleukin-8 expression in Helicobacter pylori-associated gastritis. Infect Immun 2001; 69:81-8. [PMID: 11119492 PMCID: PMC97858 DOI: 10.1128/iai.69.1.81-88.2001] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Colonization of the gastric mucosa with Helicobacter pylori is associated with a dense infiltration of granulocytes into the lamina propria in the active phase of gastritis. In this study, we investigated the involvement of epithelial cell-derived neutrophil-activating protein 78 (ENA-78) in development of H. pylori-associated gastritis. Antral biopsies from 27 patients with H. pylori-associated gastritis and 25 from H. pylori-negative individuals were first analyzed for ENA-78 and interleukin-8 (IL-8) mRNA by semiquantitative reverse transcription (RT)-PCR. In H. pylori-positive patients, significantly elevated levels were found for both chemokines (P<0.05). Only IL-8 mRNA levels differed significantly (P<0.05) in H. pylori-infected individuals who had serum antibodies for cytotoxin-associated protein CagA versus H. pylori-infected CagA-negative persons. Quantification of ENA-78 transcript levels by competitive RT-PCR yielded a significant 45-fold upregulation for ENA-78 transcripts in biopsies of H. pylori-positive versus H. pylori-negative patients (P<0.05). In contrast to earlier findings with IL-8, the degree of ENA-78 mRNA upregulation was independent of the grade of activity of gastritis. Immunofluorescence studies on tissues of antral biopsies localized ENA-78 protein expression mainly to the gastric epithelium of H. pylori-positive patients, while control tissues were negative. Upregulation of ENA-78 and IL-8 mRNA and protein expression was also observed in an in vitro system using a gastric adenocarcinoma cell line. Only viable H. pylori yielded a strong ENA-78 and IL-8 induction, while H. pylori outer membrane proteins or water-soluble proteins had no significant effect. These data provide evidence for the importance of both IL-8 and ENA-78 in the development and perpetuation of H. pylori-associated gastritis.
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Addison CL, Daniel TO, Burdick MD, Liu H, Ehlert JE, Xue YY, Buechi L, Walz A, Richmond A, Strieter RM. The CXC chemokine receptor 2, CXCR2, is the putative receptor for ELR+ CXC chemokine-induced angiogenic activity. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 165:5269-77. [PMID: 11046061 DOI: 10.4049/jimmunol.165.9.5269] [Citation(s) in RCA: 433] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We have previously shown that members of the ELR(+) CXC chemokine family, including IL-8; growth-related oncogenes alpha, beta, and gamma; granulocyte chemotactic protein 2; and epithelial neutrophil-activating protein-78, can mediate angiogenesis in the absence of preceding inflammation. To date, the receptor on endothelial cells responsible for chemotaxis and neovascularization mediated by these ELR(+) CXC chemokines has not been determined. Because all ELR(+) CXC chemokines bind to CXC chemokine receptor 2 (CXCR2), we hypothesized that CXCR2 is the putative receptor for ELR(+) CXC chemokine-mediated angiogenesis. To test this postulate, we first determined whether cultured human microvascular endothelial cells expressed CXCR2. CXCR2 was detected in human microvascular endothelial cells at the protein level by both Western blot analysis and immunohistochemistry using polyclonal Abs specific for human CXCR2. To determine whether CXCR2 played a functional role in angiogenesis, we determined whether this receptor was involved in endothelial cell chemotaxis. We found that microvascular endothelial cell chemotaxis in response to ELR(+) CXC chemokines was inhibited by anti-CXCR2 Abs. In addition, endothelial cell chemotaxis in response to ELR(+) CXC chemokines was sensitive to pertussis toxin, suggesting a role for G protein-linked receptor mechanisms in this biological response. The importance of CXCR2 in mediating ELR(+) CXC chemokine-induced angiogenesis in vivo was also demonstrated by the lack of angiogenic activity induced by ELR(+) CXC chemokines in the presence of neutralizing Abs to CXCR2 in the rat corneal micropocket assay, or in the corneas of CXCR2(-/-) mice. We thus conclude that CXCR2 is the receptor responsible for ELR(+) CXC chemokine-mediated angiogenesis.
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MESH Headings
- Administration, Topical
- Amino Acid Motifs
- Amino Acid Sequence
- Angiogenesis Inhibitors/physiology
- Animals
- Antibodies, Blocking/physiology
- Cell Migration Inhibition
- Cells, Cultured
- Chemokines, CXC/administration & dosage
- Chemokines, CXC/chemistry
- Chemokines, CXC/physiology
- Cornea/blood supply
- Endothelium, Vascular/cytology
- Endothelium, Vascular/immunology
- Endothelium, Vascular/metabolism
- Endothelium, Vascular/physiology
- Humans
- Immune Sera/pharmacology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Microcirculation/cytology
- Microcirculation/immunology
- Microcirculation/metabolism
- Molecular Sequence Data
- Neovascularization, Physiologic/genetics
- Neovascularization, Physiologic/immunology
- Pertussis Toxin
- Rats
- Receptors, Interleukin-8B/biosynthesis
- Receptors, Interleukin-8B/genetics
- Receptors, Interleukin-8B/immunology
- Receptors, Interleukin-8B/metabolism
- Virulence Factors, Bordetella/pharmacology
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Viefhaus T, Walz A, Niemeyer M, Schwarz W, Weidlein J. [{(CH3)3Si}3C-Li-C{Si(CH3)3}3][Li · 3(OC4H8)] und {(CH3)3Si}3C-Li · O=C(Si(CH3)3)2, zwei neue Addukte des Lithium-trisylmethanids. Z Anorg Allg Chem 2000. [DOI: 10.1002/1521-3749(200010)626:10<2040::aid-zaac2040>3.0.co;2-m] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Zeidler R, Mysliwietz J, Csánady M, Walz A, Ziegler I, Schmitt B, Wollenberg B, Lindhofer H. The Fc-region of a new class of intact bispecific antibody mediates activation of accessory cells and NK cells and induces direct phagocytosis of tumour cells. Br J Cancer 2000; 83:261-6. [PMID: 10901380 PMCID: PMC2363488 DOI: 10.1054/bjoc.2000.1237] [Citation(s) in RCA: 131] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/1999] [Revised: 03/02/2000] [Accepted: 03/10/2000] [Indexed: 12/27/2022] Open
Abstract
Bispecific antibodies (bsAb) are considered as promising tools for the elimination of disseminated tumour cells in a minimal residual disease situation. The bsAb-mediated recruitment of an immune effector cell in close vicinity of a tumour cell is thought to induce an antitumoural immune response. However, classical bispecific molecules activate only a single class of immune effector cell that may not yield optimal immune responses. We therefore constructed an intact bispecific antibody, BiUII (anti-CD3 x anti-EpCAM), that not only recognizes tumour cells and T lymphocytes with its two binding arms, but also binds and activates Fcgamma-receptor positive accessory cells through its Fc-region. We have demonstrated recently that activated accessory cells contribute to the bsAb-induced antitumoural activity. We now analyse this stimulation in more detail and demonstrate here the BiUII-induced upregulation of activation markers like CD83 and CD95 on accessory cells and the induction of neopterin and biopterin synthesis. Experiments with pure cell subpopulations revealed binding of BiUII to CD64+ accessory cells and CD16+ NK cells, but not to CD32+ B lymphocytes. We provide further evidence for the importance of the Fc-region in that this bispecific molecule stimulates Fcgamma-R-positive accessory cells to eliminate tumour cells in vitro by direct phagocytosis.
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Saurer L, Reber P, Schaffner T, Büchler MW, Buri C, Kappeler A, Walz A, Friess H, Mueller C. Differential expression of chemokines in normal pancreas and in chronic pancreatitis. Gastroenterology 2000; 118:356-67. [PMID: 10648464 DOI: 10.1016/s0016-5085(00)70218-6] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND & AIMS Cellular infiltrates are present already in early stages of chronic pancreatitis. The mechanisms responsible for their recruitment are unknown. Hence, we determined the differential expression of chemokine genes and their cellular sources in normal and affected pancreatic tissues. METHODS Pancreatic tissues from 23 patients with chronic pancreatitis and from 4 normal controls were subjected to in situ hybridization for detecting messenger RNA (mRNA) of the chemokine genes interleukin 8, ENA-78, MIG, MCP-1, and I-309. RESULTS Normal pancreatic tissues lack cells expressing mRNA for IL-8, ENA-78, MIG, and MCP-1. In contrast, pancreatic lobuli with mild to moderate signs of tissue alterations strongly expressed MCP-1 mRNA in centroacinar ducts, endothelia, fibroblasts, macrophages, T cells, and occasionally in nerves. Interleukin 8 and ENA-78 mRNA is preferentially detected in centroacinar ducts of pancreatic lobuli with more advanced alterations. Variable numbers of pancreas-infiltrating T cells express MIG mRNA. I-309 mRNA, however, is consistently observed in normal acini and in tissue with mild to moderate signs of tissue alterations. CONCLUSIONS The observed differential expression of distinct chemokine genes in pancreatic parenchyma and infiltrates from patients with chronic pancreatitis strongly suggests an involvement of distinct chemokines in the initiation and perpetuation of disease.
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