Strain diversity of Lymeborreliosis species

Topics with information and discussion about published studies related to Lyme disease and other tick-borne diseases.
Post Reply
User avatar
Yvonne
Posts: 2421
Joined: Fri 27 Jul 2007 16:02

Strain diversity of Lymeborreliosis species

Post by Yvonne » Tue 2 Oct 2007 9:43

Sequence typing reveals extensive strain diversity
of the Lymeborreliosis agents Borrelia burgdorferi
in North America and Borrelia afzelii in Europe

http://mic.sgmjournals.org/cgi/reprint/150/6/1741.pdf
Listen to all,
plucking a feather from every passing goose,
but follow no one absolutely

Nick
Posts: 299
Joined: Wed 19 Sep 2007 19:10
Location: Zeeland, Netherlands

Re: Strain diversity of Lymeborreliosis species

Post by Nick » Tue 2 Oct 2007 13:21

one of the problems with Borrelia is that what you put into an organism is not the same (on the genetic and antigenic level) as what comes out after a few generations. This applies to some of the outer proteins like OSPC and Vlse, but probably also to other parts of the genetic makeup. This is a major challenge for the immune system, it makes a lot of research extremely difficult and might invalidate the concept of 'strains' for Bb. The lifecycle and other adaptive forms (cyst, CWD? spore??) make all this even more complicated.

minx
Posts: 96
Joined: Fri 27 Jul 2007 13:50

Re: Strain diversity of Lymeborreliosis species

Post by minx » Wed 3 Oct 2007 21:19

Following article suggests that there is a relationship between OspC and invasiveness of the Bb:

http://jcm.asm.org/cgi/content/full/41/11/5059

Genetic Diversity among Borrelia Strains Determined by Single-Strand Conformation Polymorphism Analysis of the ospC Gene and Its Association with Invasiveness
Vanessa Lagal,1* Danièle Postic,1 Eva Ruzic-Sabljic,2 and Guy Baranton1

Unité de Bactériologie Moléculaire et Médicale, Institut Pasteur, 75724 Cedex 15, France,1 Institute of Microbiology and Immunology, 1000 Ljubljana, Slovenia2

Received 30 October 2002/ Returned for modification 5 March 2003/ Accepted 8 June 2003


ABSTRACT

Lyme borreliosis (LB) is a tick-borne spirochetal infection caused by three Borrelia species: Borrelia afzelii, B. garinii, and B. burgdorferi sensu stricto. LB evolves in two stages: a skin lesion called erythema migrans and later, different disseminated forms (articular, neurological, cardiac...). Previous research based on analysis of ospC sequences allowed the definition of 58 groups (divergence of <2% within a group and >8% between groups). Only 10 of these groups include all of the strains isolated from disseminated forms that are considered invasive. The aim of this study was to determine whether or not invasive strains belong to restricted ospC groups by testing human clinical strains isolated from disseminated forms. To screen for ospC genetic diversity, we used single-strand conformation polymorphism (SSCP) analysis. Previously known ospC sequences from 44 different strains were first tested, revealing that each ospC group had a characteristic SSCP pattern. Therefore, we studied 80 disseminated-form isolates whose ospC sequences were unknown. Of these, 28 (35%) belonged to previously known invasive groups. Moreover, new invasive groups were identified: six of B. afzelii, seven of B. garinii, and one of B. burgdorferi sensu stricto. This study confirmed that invasive strains are not distributed among all 69 ospC groups but belong to only 24 groups. This suggests that OspC may be involved in the invasiveness of B. burgdorferi.
I thought this to be an interesting observation:
Each pathogenic Borrelia species is predominantly associated with a given late clinical manifestation: B. afzelii with cutaneous manifestations, B. garinii with neurologic manifestations, and B. burgdorferi sensu stricto with articular manifestations (1, 22). However, sequences from strains isolated from each clinical manifestation are scattered along the tree (data not shown). Fifteen strains included in our study were responsible for a clinical manifestation different from that expected (six B. afzelii strains isolated from CSF, five B. garinii strains from ACA, two B. burgdorferi sensu stricto strains from ACA, one B. garinii strain from LBC, and one B. burgdorferi sensu stricto strain from CSF; Table 2).

Nick
Posts: 299
Joined: Wed 19 Sep 2007 19:10
Location: Zeeland, Netherlands

Re: Strain diversity of Lymeborreliosis species

Post by Nick » Sat 6 Oct 2007 14:30

it is suggested that OSPC is involved in early immune evasion and targeting specific hosts /tissues. So depending on the OSPC version Bb will target (prefer) a certain type of tissue. The targeting could be a result of attachment factors (Bb seems to attach to certain structures on the cell membrane) or of some kind of stealth technology (e.g. similarity between OSPC outer regions and human antigenes in the specific tissue). Some researchers see evidence for extensive OSPC gene transfer, both in local Bb populations and between different species. So there is no fixed relation between a certain Bb species/strain and the target tissue. Sorry, no references ...

Post Reply