JAC Advance Access originally published online on June 9, 2004
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Journal of Antimicrobial Chemotherapy 2004 54(1):288-289; doi:10.1093/jac/dkh288
JAC vol.54 no.1 © The British Society for Antimicrobial Chemotherapy 2004; all rights reserved.
Correspondence |
Inhibition of TNF-
production in THP-1 macrophages by glatiramer acetate does not alter their susceptibility to infection by Listeria monocytogenes and does not impair the efficacy of ampicillin or moxifloxacin against intracellular bacteria
Unité de pharmacologie cellulaire et moléculaire, Université catholique de Louvain, 73.70 avenue E. Mounier 73, B-1200 Brussels, Belgium
Keywords: L. monocytogenes , listeriosis
Sir,
Listeriosis is one of the potential adverse effects of TNF-
-neutralizing treatments.1 Glatiramer (copolymer 1; COPAXONE), a mixed, random polymer of Ala, Glu, Lys and Tyr used in the treatment of relapsing–remitting multiple sclerosis2 blocks the secretion of TNF- from IFN-
- and endotoxin-stimulated THP-1 macrophages.3 We have, therefore, examined the influence of glatiramer on the ability of IFN- to contain Listeria infection and on the activity of ampicillin and moxifloxacin to kill intraphagocytic bacteria in THP-1 macrophages. Glatiramer [CAS Registry no. 147 245-92-9; batch no. 242908102: average molecular weight, 7500 Da (limits, 4200–16 350); amino acid content (molecular fraction) L-Glu, 0.139; L-Ala, 0.432; L-Tyr, 0.091; L-Lys, 0.338; total amino acid residue content, 87.9%; bacterial endotoxin content, <0.25 endotoxin units/mg] was kindly received from Teva Pharmaceuticals Industries (Petah Tiqua, Israel). All experimental procedures and assay methods have been described in our previous publications.4,5 We used a concentration of glatiramer of 20 mg/L, which was both non-toxic (based on lactate dehydrogenase release) and effective in blocking the production of TNF- in THP-1 cells.3
Glatiramer (20 mg/L) did not influence the intrinsic antimicrobial activity of ampicillin or moxifloxacin towards L. monocytogenes, based on MIC determinations in broth [0.3±0.1 and 0.5±0.1 mg/L (arithmetic dilutions) for ampicillin and moxifloxacin, respectively]. Unstimulated cells produced only negligible amounts of TNF- and glatiramer did not alter this behaviour. In contrast, the medium of cells exposed to IFN- (100 units/mL; 24 h) contained 38.3±6.0 ng/L of TNF-, and this concentration was decreased by 
2/3 in the presence of glatiramer. With infected cells, TNF- production remained low in unstimulated cells and unaffected by the presence of glatiramer, whereas it amounted to 31.6±1.2 ng/L (5 h post-phagocytosis) in IFN--stimulated cells (24 h prior to infection). This production was again decreased by 2/3 if glatiramer was present. Glatiramer did not significantly modify the capacity of THP-1 macrophages to phagocytose L. monocytogenes. Figure 1 shows that glatiramer did not modify the growth of intracellular L. monocytogenes compared with untreated cells in the 24 h model (this model uses gentamicin at a concentration of 2 x its MIC to prevent the extracellular growth of L. monocytogenes). No change was seen either in the 5 h model (data not shown). As previously described,6 IFN- impaired the intracellular growth of L. monocytogenes by 50%, and glatiramer did not modify this effect. When infected cells were exposed to ampicillin for 24 h after phagocytosis, the bacterial load was reduced by 1.7 log compared with the original, post-phagocytosis inoculum. Glatiramer, IFN-, or the combination of glatiramer and IFN- did not significantly modify this effect of ampicillin. In the next series of experiments, we examined the activity of moxifloxacin (4 mg/L) using the 5 h model. We observed a decrease in the post-phagocytosis inoculum of 1.34±0.03, 1.26±0.16, 1.31±0.07 and 1.32±0.07 log10 units for cells treated with moxifloxacin alone, glatiramer and moxifloxacin, IFN- and moxifloxacin, and the combination of glatiramer, IFN- and moxifloxacin, respectively. In parallel experiments, we examined the influence of glatiramer on the accumulation of moxifloxacin and no effect was seen [apparent cellular to extracellular drug concentration ratios at 2 h of 9.6±2.0 in controls versus 9.4±1.1 in cells exposed to glatiramer (20 mg/L) during the uptake period; similar values were found for cells pre-exposed to glatiramer (20 mg/L) for 24 h]. Glatiramer did not influence the accumulation of three other quinolones (ciprofloxacin, levofloxacin and garenoxacin).
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Our data, therefore, show that the production of TNF-
is not critical in IFN--stimulated THP-1 cells for anti-Listeria activity. The model used has been validated to analyse the behaviour of intracellular L. monocytogenes with respect to the action of cytokines5,6 and to the influence of antibiotics. THP-1 cells display functional receptors for TNF-7 and their presence in the cell line used here has been confirmed (J. Zanon, unpublished data). TNF- may be more a potentializer of IFN-8 than a true effector for the control of L. monocytogenes growth in THP-1 cells. Because intracellular multiplication of L. monocytogenes is an important determinant in the persistence and the spread of the infection, our results suggest that glatiramer (i) may actually not increase this risk, and (ii) may not adversely affect ampicillin or quinolone-based antibiotic treatments should the necessity arise. This will need to be confirmed by in vivo studies.
Acknowledgements
Mrs N. Aguilera provided critical help in some of the experiments described in this paper and Ms M. C. Cambier maintained the cell culture line. S. C. was Boursier of the Belgian Fonds pour la Formation à la Recherche dans l'Industrie et l'Agriculture (F.R.I.A.), is F. V. B. Chercheur Qualifié of the Belgian Fonds National de la Recherche Scientifique (F.N.R.S.). This work was supported by the Belgian Fonds de la Recherche Scientifique Médicale (F.R.S.M.; grant no. 3.4.612.00 F). Aventis Pharma s.a., Brussels, Belgium, provided the sample of glatiramer used in this study.
Footnotes
* Corresponding author. Tel: +32-2-762-21-36; Fax: +32-2-764-73-73; Email: tulkens{at}facm.ucl.ac.be
Present address: Department of Veterinary Science and Microbiology, University of Arizona, 1117 E. Lowell, Bldg. 90, Room 306, Tucson, AZ 85721, USA 
References
1 . Slifman, N. R., Gershon, S. K., Lee, J. H. et al. (2003). Listeria monocytogenes infection as a complication of treatment with tumor necrosis factor alpha-neutralizing agents. Arthritis and Rheumatism 48, 319–24.[CrossRef][Web of Science][Medline]
2
.
Johnson, K. P., Brooks, B. R., Ford, C. C. et al. (2000). Sustained clinical benefits of glatiramer acetate in relapsing multiple sclerosis patients observed for 6 years. Copolymer 1 Multiple Sclerosis Study Group. Multiple Sclerosis 6, 255–66.
3 . Li, Q., Milo, R., Panitch, H. et al. (1998). Glatiramer acetate blocks the activation of THP-1 cells by interferon-gamma. European Journal of Pharmacology 342, 303–10.[CrossRef][Web of Science][Medline]
4
.
Carryn, S., Van Bambeke, F., Mingeot-Leclercq, M. P. et al. (2002). Comparative intracellular (THP-1 macrophage) and extracellular activities of beta-lactams, azithromycin, gentamicin, and fluoroquinolones against Listeria monocytogenes at clinically relevant concentrations. Antimicrobial Agents and Chemotherapy 46, 2095–103.
5
.
Carryn, S., Van de Velde, S., Van Bambeke, F. et al. (2004). Impairment of Listeria monocytogenes growth in THP-1 macrophages by granulocyte-macrophage colony stimulating factor. Roles of TNF- and nitric oxide release. Journal of Infectious Diseases 189, 2101–9.[CrossRef][Web of Science][Medline]
6
.
Ouadrhiri, Y., Scorneaux, B., Sibille, Y. et al. (1999). Mechanism of the intracellular killing and modulation of antibiotic susceptibility of Listeria monocytogenes in THP-1 macrophages activated by gamma interferon. Antimicrobial Agents and Chemotherapy 43, 1242–51.
7 . Abe, Y., Gatanaga, M., Osuka, Y. et al. (1993). Role of 55- and 75-kDa tumor necrosis factor membrane receptors in the regulation of intercellular adhesion molecules-1 expression by HL-60 human promyelocytic leukemia cells in vitro. Journal of Immunology 150, 5070–9.[Abstract]
8
.
Nakane, A., Minagawa, T., Kohanawa, M. et al. (1989). Interactions between endogenous gamma interferon and tumor necrosis factor in host resistance against primary and secondary Listeria monocytogenes infections. Infection and Immunity 57, 3331–7.
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