Abstract
Ehrlichia chaffeensis is an obligate intracellular bacterium which infects cells of the macrophage/monocyte lineage. To test whether gamma interferon (IFN-gamma) inhibits infection of monocytes with E. chaffeensis, human peripheral blood monocytes were incubated with recombinant human IFN-gamma for 3 h and then exposed to E. chaffeensis. With 2,000 U of IFN-gamma per ml, maximal inhibition of infection by E. chaffeensis was observed. THP-1 cells, a human monocyte cell line, pretreated with phorbol myristic acetate or not pretreated, were incubated with various concentrations of IFN-gamma. Maximum inhibition was obtained at 1,000 U of IFN-gamma per ml with phorbol myristic acetate-treated THP-1 cells. However, nontreated cells did not achieve a similar level of anti-ehrlichial activity even with 10,000 U of IFN-gamma per ml. IFN-gamma given within 6 h postinfection was effective in inhibiting E. chaffeensis. Nitric oxide production was not demonstrated in the monocyte medium incubated with IFN-gamma and E. chaffeensis. None of the reactive oxygen intermediate scavengers tested blocked the IFN-gamma-induced anti-ehrlichial activity. Deferoxamine, an intracellular iron chelator, at 15 microM completely inhibited the survival of E. chaffeensis. Iron-saturated transferrin at 1.67 mg/ml completely reversed the IFN-gamma-induced ehrlichial killing. These results indicate that (i) E. chaffeensis is sensitive to intracytoplasmic iron depletion, (ii) E. chaffeensis is sensitive to IFN-gamma-induced killing, and (iii) the anti-ehrlichial activity induced in human monocytes by IFN-gamma is mediated by limitation of available cytoplasmic iron and is not due to the generation of reactive oxygen intermediates or nitric oxide.
Full text
PDF






Images in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Anderson B. E., Dawson J. E., Jones D. C., Wilson K. H. Ehrlichia chaffeensis, a new species associated with human ehrlichiosis. J Clin Microbiol. 1991 Dec;29(12):2838–2842. doi: 10.1128/jcm.29.12.2838-2842.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Anderson B. E., Sims K. G., Olson J. G., Childs J. E., Piesman J. F., Happ C. M., Maupin G. O., Johnson B. J. Amblyomma americanum: a potential vector of human ehrlichiosis. Am J Trop Med Hyg. 1993 Aug;49(2):239–244. doi: 10.4269/ajtmh.1993.49.239. [DOI] [PubMed] [Google Scholar]
- Babior B. M. The respiratory burst of phagocytes. J Clin Invest. 1984 Mar;73(3):599–601. doi: 10.1172/JCI111249. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Baynes R., Bukofzer G., Bothwell T., Bezwoda W., Macfarlane B. Transferrin receptors and transferrin iron uptake by cultured human blood monocytes. Eur J Cell Biol. 1987 Jun;43(3):372–376. [PubMed] [Google Scholar]
- Bhardwaj N., Nash T. W., Horwitz M. A. Interferon-gamma-activated human monocytes inhibit the intracellular multiplication of Legionella pneumophila. J Immunol. 1986 Oct 15;137(8):2662–2669. [PubMed] [Google Scholar]
- Byrd T. F., Horwitz M. A. Chloroquine inhibits the intracellular multiplication of Legionella pneumophila by limiting the availability of iron. A potential new mechanism for the therapeutic effect of chloroquine against intracellular pathogens. J Clin Invest. 1991 Jul;88(1):351–357. doi: 10.1172/JCI115301. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Byrd T. F., Horwitz M. A. Interferon gamma-activated human monocytes downregulate transferrin receptors and inhibit the intracellular multiplication of Legionella pneumophila by limiting the availability of iron. J Clin Invest. 1989 May;83(5):1457–1465. doi: 10.1172/JCI114038. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dawson J. E., Anderson B. E., Fishbein D. B., Sanchez J. L., Goldsmith C. S., Wilson K. H., Duntley C. W. Isolation and characterization of an Ehrlichia sp. from a patient diagnosed with human ehrlichiosis. J Clin Microbiol. 1991 Dec;29(12):2741–2745. doi: 10.1128/jcm.29.12.2741-2745.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dawson J. E., Ewing S. A. Susceptibility of dogs to infection with Ehrlichia chaffeensis, causative agent of human ehrlichiosis. Am J Vet Res. 1992 Aug;53(8):1322–1327. [PubMed] [Google Scholar]
- Ding A. H., Nathan C. F., Stuehr D. J. Release of reactive nitrogen intermediates and reactive oxygen intermediates from mouse peritoneal macrophages. Comparison of activating cytokines and evidence for independent production. J Immunol. 1988 Oct 1;141(7):2407–2412. [PubMed] [Google Scholar]
- Drapier J. C., Hibbs J. B., Jr Murine cytotoxic activated macrophages inhibit aconitase in tumor cells. Inhibition involves the iron-sulfur prosthetic group and is reversible. J Clin Invest. 1986 Sep;78(3):790–797. doi: 10.1172/JCI112642. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dumler J. S., Dawson J. E., Walker D. H. Human ehrlichiosis: hematopathology and immunohistologic detection of Ehrlichia chaffeensis. Hum Pathol. 1993 Apr;24(4):391–396. doi: 10.1016/0046-8177(93)90087-w. [DOI] [PubMed] [Google Scholar]
- Eng T. R., Harkess J. R., Fishbein D. B., Dawson J. E., Greene C. N., Redus M. A., Satalowich F. T. Epidemiologic, clinical, and laboratory findings of human ehrlichiosis in the United States, 1988. JAMA. 1990 Nov 7;264(17):2251–2258. [PubMed] [Google Scholar]
- Green L. C., Wagner D. A., Glogowski J., Skipper P. L., Wishnok J. S., Tannenbaum S. R. Analysis of nitrate, nitrite, and [15N]nitrate in biological fluids. Anal Biochem. 1982 Oct;126(1):131–138. doi: 10.1016/0003-2697(82)90118-x. [DOI] [PubMed] [Google Scholar]
- Grey S., Hau H., Salem H. H., Hancock W. W. Selective effects of protein C on activation of human monocytes by lipopolysaccharide, interferon-gamma, or PMA: modulation of effects on CD11b and CD14 but not CD25 or CD54 induction. Transplant Proc. 1993 Oct;25(5):2913–2914. [PubMed] [Google Scholar]
- Guerrero A., Fishbein D. B., Mesa E., Escudero R. Infección humana por Ehrlichia canis en España? Med Clin (Barc) 1991 Feb 16;96(6):236–237. [PubMed] [Google Scholar]
- Haziot A., Chen S., Ferrero E., Low M. G., Silber R., Goyert S. M. The monocyte differentiation antigen, CD14, is anchored to the cell membrane by a phosphatidylinositol linkage. J Immunol. 1988 Jul 15;141(2):547–552. [PubMed] [Google Scholar]
- Heiple J. M., Taylor D. L. pH changes in pinosomes and phagosomes in the ameba, Chaos carolinensis. J Cell Biol. 1982 Jul;94(1):143–149. doi: 10.1083/jcb.94.1.143. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Horwitz M. A., Maxfield F. R. Legionella pneumophila inhibits acidification of its phagosome in human monocytes. J Cell Biol. 1984 Dec;99(6):1936–1943. doi: 10.1083/jcb.99.6.1936. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Horwitz M. A., Silverstein S. C. Activated human monocytes inhibit the intracellular multiplication of Legionnaires' disease bacteria. J Exp Med. 1981 Nov 1;154(5):1618–1635. doi: 10.1084/jem.154.5.1618. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Iyengar R., Stuehr D. J., Marletta M. A. Macrophage synthesis of nitrite, nitrate, and N-nitrosamines: precursors and role of the respiratory burst. Proc Natl Acad Sci U S A. 1987 Sep;84(18):6369–6373. doi: 10.1073/pnas.84.18.6369. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Jacobs A. Low molecular weight intracellular iron transport compounds. Blood. 1977 Sep;50(3):433–439. [PubMed] [Google Scholar]
- Morais J. D., Dawson J. E., Greene C., Filipe A. R., Galhardas L. C., Bacellar F. First European case of ehrlichiosis. Lancet. 1991 Sep 7;338(8767):633–634. doi: 10.1016/0140-6736(91)90644-5. [DOI] [PubMed] [Google Scholar]
- Murray H. W., Juangbhanich C. W., Nathan C. F., Cohn Z. A. Macrophage oxygen-dependent antimicrobial activity. II. The role of oxygen intermediates. J Exp Med. 1979 Oct 1;150(4):950–964. doi: 10.1084/jem.150.4.950. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Nathan C. F., Horowitz C. R., de la Harpe J., Vadhan-Raj S., Sherwin S. A., Oettgen H. F., Krown S. E. Administration of recombinant interferon gamma to cancer patients enhances monocyte secretion of hydrogen peroxide. Proc Natl Acad Sci U S A. 1985 Dec;82(24):8686–8690. doi: 10.1073/pnas.82.24.8686. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Nathan C. F., Murray H. W., Wiebe M. E., Rubin B. Y. Identification of interferon-gamma as the lymphokine that activates human macrophage oxidative metabolism and antimicrobial activity. J Exp Med. 1983 Sep 1;158(3):670–689. doi: 10.1084/jem.158.3.670. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Park J., Rikihisa Y. Inhibition of Ehrlichia risticii infection in murine peritoneal macrophages by gamma interferon, a calcium ionophore, and concanavalin A. Infect Immun. 1991 Oct;59(10):3418–3423. doi: 10.1128/iai.59.10.3418-3423.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Park J., Rikihisa Y. L-arginine-dependent killing of intracellular Ehrlichia risticii by macrophages treated with gamma interferon. Infect Immun. 1992 Sep;60(9):3504–3508. doi: 10.1128/iai.60.9.3504-3508.1992. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rikihisa Y. The tribe Ehrlichieae and ehrlichial diseases. Clin Microbiol Rev. 1991 Jul;4(3):286–308. doi: 10.1128/cmr.4.3.286. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Schneemann M., Schoedon G., Hofer S., Blau N., Guerrero L., Schaffner A. Nitric oxide synthase is not a constituent of the antimicrobial armature of human mononuclear phagocytes. J Infect Dis. 1993 Jun;167(6):1358–1363. doi: 10.1093/infdis/167.6.1358. [DOI] [PubMed] [Google Scholar]
- Sibley L. D., Weidner E., Krahenbuhl J. L. Phagosome acidification blocked by intracellular Toxoplasma gondii. 1985 May 30-Jun 5Nature. 315(6018):416–419. doi: 10.1038/315416a0. [DOI] [PubMed] [Google Scholar]
- Tsuchiya S., Kobayashi Y., Goto Y., Okumura H., Nakae S., Konno T., Tada K. Induction of maturation in cultured human monocytic leukemia cells by a phorbol diester. Cancer Res. 1982 Apr;42(4):1530–1536. [PubMed] [Google Scholar]
- Tsuchiya S., Yamabe M., Yamaguchi Y., Kobayashi Y., Konno T., Tada K. Establishment and characterization of a human acute monocytic leukemia cell line (THP-1). Int J Cancer. 1980 Aug;26(2):171–176. doi: 10.1002/ijc.2910260208. [DOI] [PubMed] [Google Scholar]
- Uhaa I. J., MacLean J. D., Greene C. R., Fishbein D. B. A case of human ehrlichiosis acquired in Mali: clinical and laboratory findings. Am J Trop Med Hyg. 1992 Feb;46(2):161–164. doi: 10.4269/ajtmh.1992.46.161. [DOI] [PubMed] [Google Scholar]