VlsE antigenic variation and Lyme persistence

Topics with information and discussion about published studies related to Lyme disease and other tick-borne diseases.
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Joe Ham
Posts: 489
Joined: Fri 27 Jul 2007 6:15
Location: New Mexico, USA

VlsE antigenic variation and Lyme persistence

Post by Joe Ham » Sun 2 Sep 2007 0:08

The role of VlsE antigenic variation in the Lyme disease spirochete: persistence through a mechanism that differs from other pathogens

Troy Bankhead and George Chaconas*
Departments of Biochemistry and Molecular Biology, and Microbiology and Infectious Diseases, University of Calgary, Calgary, Alberta T2N 4 N1, Canada.  2007-9

Summary 

The linear plasmid, lp28-1, is required for persistent infection by the Lyme disease spirochete, Borrelia burgdorferi. This plasmid contains the vls antigenic variation locus, which has long been thought to be important for immune evasion.

However, the role of the vls locus as a virulence factor during mammalian infection has not been clearly defined.

We report the successful removal of the vls locus through telomere resolvase-mediated targeted deletion, and demonstrate the absolute requirement of this lp28-1 component for persistence in the mouse host.

Moreover, successful infection of C3H/HeN mice with an lp28-1 plasmid in which the left portion was deleted excludes participation of other lp28-1 non-vls genes in spirochete virulence, persistence and the process of recombinational switching at vlsE.

Data are also presented that cast doubt on an immune evasion mechanism whereby VlsE directly masks other surface antigens similar to what has been observed for several other pathogens that undergo recombinational antigenic variation.

http://www.blackwell-synergy.com/doi/ab ... 07.05895.x

Joe Ham
Posts: 489
Joined: Fri 27 Jul 2007 6:15
Location: New Mexico, USA

Re: VlsE antigenic variation and Lyme persistence

Post by Joe Ham » Tue 25 Dec 2007 18:48

0019-9567/04/$08.00+0     DOI: 10.1128/IAI.72.10.5759-5767.2004
Copyright © 2004 ,American Society for Microbiology . All Rights Reserved.

Borrelia burgdorferi Changes Its Surface Antigenic Expression in Response to Host Immune Responses
Fang Ting Liang, 1Jun Yan, 1M. Lamine Mbow, 2Steven L. Sviat, 3Robert D. Gilmore, 3Mark Mamula, 1and Erol Fikrig 1*
http://iai.asm.org/cgi/content/abstract/72/10/5759

Section of Rheumatology, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, 1Centocor, Inc., Malvern, Pennsylvania, 2Bacterial Zoonoses Branch, Division of Vector-Borne Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado 3

Received 7 May 2004/ Returned for modification 17 June 2004/ Accepted 25 June 2004

The Lyme disease spirochete, Borrelia burgdorferi , causes persistent mammalian infection despite the development of vigorous immune responses against the pathogen.

To examine spirochetal phenotypes that dominate in the hostile immune environment, the mRNA transcripts of four prototypic surface lipoproteins, decorin-binding protein A (DbpA), outer surface protein C (OspC), BBF01, and VlsE, were analyzed by quantitative reverse transcription-PCR under various immune conditions.

We demonstrate that B. burgdorferi changes its surface antigenic expression in response to immune attack.
dbpA expression was unchanged while the spirochetes decreased ospC expression by 446 times and increased BBF01 and vlsE expression up to 20 and 32 times, respectively, under the influence of immune pressure generated in immunocompetent mice during infection. This change in antigenic expression could be induced by passively immunizing infected severe combined immunodeficiency mice with specific Borrelia antisera or OspC antibody and appears to allow B. burgdorferi to resist immune attack.

* Corresponding author. Mailing address: Section of Rheumatology, Department of Internal Medicine, Yale University School of Medicine, S525A, 300 Cedar St., New Haven, CT 06520-8031. Phone: (203) 785-2453. Fax: (203) 785-7053. E-mail: erol.fikrig@yale.edu .

Editor: D. L. Burns

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