This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Supplemental material
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Huang, H.
Right arrow Articles by Rikihisa, Y.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Huang, H.
Right arrow Articles by Rikihisa, Y.

 Previous Article  |  Next Article 

Infection and Immunity, August 2008, p. 3405-3414, Vol. 76, No. 8
0019-9567/08/$08.00+0     doi:10.1128/IAI.00056-08
Copyright © 2008, American Society for Microbiology. All Rights Reserved.

Proteomic Analysis of and Immune Responses to Ehrlichia chaffeensis Lipoproteins {triangledown} ,{ddagger}

Haibin Huang ,1,{dagger},§ Mingqun Lin,1,{dagger} Xueqi Wang,1,{dagger} Takane Kikuchi,1 Heather Mottaz,2 Angela Norbeck,2 and Yasuko Rikihisa1*

Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio 43210,1 Environmental Molecular Science Laboratory, Pacific Northwest National Laboratory, Richland, Washington 993522

Received 15 January 2008/ Returned for modification 12 February 2008/ Accepted 9 May 2008

Ehrlichia chaffeensis is an obligately intracellular gram-negative bacterium and is the etiologic agent of human monocytic ehrlichiosis (HME). Although E. chaffeensis induces the generation of several cytokines and chemokines by leukocytes, E. chaffeensis lacks lipopolysaccharide and peptidoglycan. Bioinfomatic analysis of the E. chaffeensis genome, however, predicted genes encoding 15 lipoproteins and 3 posttranslational lipoprotein-processing enzymes. The present study showed that by use of multidimensional liquid chromatography followed by tandem mass spectrometry, all predicted lipoproteins as well as lipoprotein-processing enzymes were expressed by E. chaffeensis cultured in the human promyelocytic leukemia cell line HL-60. Consistent with this observation, a signal peptidase II inhibitor, globomycin, was found to inhibit E. chaffeensis infection and lipoprotein processing in HL-60 cell culture. To study in vivo E. chaffeensis lipoprotein expression and host immune responses to E. chaffeensis lipoproteins, 13 E. chaffeensis lipoprotein genes were cloned into a mammalian expression vector. When the DNA constructs were inoculated into naïve dogs, or when dogs were infected with E. chaffeensis, the animals developed delayed-type hypersensitivity reactions at cutaneous sites of the DNA construct deposition and serum antibodies to these lipoproteins. This is the first demonstration of lipoprotein expression and elicitation of immune responses by a member of the order Rickettsiales. Multiple lipoproteins expressed by E. chaffeensis in vitro and in vivo may play key roles in pathogenesis and immune responses in HME.

* Corresponding author. Mailing address: Department of Veterinary Biosciences, The Ohio State University, 1925 Coffey Rd., Columbus, OH 43210. Phone: (614) 292-5661. Fax: (614) 292-6473. E-mail: rikihisa.1{at}osu.edu

{triangledown} Published ahead of print on 19 May 2008.

{ddagger} Supplemental material for this article may be found at http://iai.asm.org/.

Editor: R. P. Morrison

{dagger} H.H., M.L., and X.W. contributed equally to this study.

§ Present address: Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605.

Infection and Immunity, August 2008, p. 3405-3414, Vol. 76, No. 8
0019-9567/08/$08.00+0     doi:10.1128/IAI.00056-08
Copyright © 2008, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Luce-Fedrow, A., Von Ohlen, T., Chapes, S. K. (2009). Ehrlichia chaffeensis Infections in Drosophila melanogaster. Infect. Immun. 77: 4815-4826 [Abstract] [Full Text]  
  • Lin, M., Zhang, C., Gibson, K., Rikihisa, Y. (2009). Analysis of complete genome sequence of Neorickettsia risticii: causative agent of Potomac horse fever. Nucleic Acids Res 37: 6076-6091 [Abstract] [Full Text]  


Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»