Excerpt:

If insufficiently treated, Lyme borreliosis can evolve into an
inflammatory disorder affecting skin, joints, and the CNS. Early
innate immunity may determine host responses targeting infection.
Thus, we sought to characterize the immediate cytokine storm
associated with exposure of PBMC to moderate levels of live
Borrelia burgdorferi. Since
Th17 cytokines are connected to host defense against
extracellular bacteria, we focused on interleukin (IL)-17 and
IL-22. Here, we report that, despite induction of inflammatory
cytokines including IL-23, IL-17 remained barely detectable in
response to B. burgdorferi. In contrast, T cell-dependent
expression of IL-22 became evident within 10 h of exposure to the
spirochetes. This dichotomy was unrelated to interferon-? but to
a large part dependent on caspase-1 and IL-1 bioactivity derived
from monocytes. In fact, IL-1? as a single stimulus induced IL-22
but not IL-17. Neutrophils display antibacterial activity against
B. burgdorferi, particularly when opsonized by antibodies. Since
neutrophilic inflammation, indicative of IL-17 bioactivity, is
scarcely observed in Erythema migrans, a manifestation of skin
inflammation after infection, protective and antibacterial
properties of IL-22 may close this gap and serve essential
functions in the initial phase of spirochete infection.

Delineation of a new species of the Borrelia burgdorferi sensu lato complex,
Borrelia americana sp.nov.

Rudenko N, Golovchenko M, Lin T, Gao L, Grubhoffer L, Oliver JH Jr.

Georgia Southern University, James H. Oliver, Jr. Institute of Arthropodology
and Parasitology, Statesboro, GA, 30460-8056, USA; Biology Centre, Institute of
Parasitology AS CR and Faculty of Sciences University of South Bohemia, eske
Budjovice, 37005, Czech Republic.

Analysis of borrelia isolates collected from ticks, birds and rodents from the
southeastern United States revealed the presence of well established populations
of Borrelia burgdorferi sensu stricto, Borrelia bissettii, Borrelia carolinensis
and Borrelia sp. nov. Multilocus sequence analysis of five genomic loci from
seven samples representing Borrelia sp. nov. isolated from nymphal Ixodes minor
collected in South Carolina showed their close relatedness to California strains
known as genomospecies 1 and separation from any other known species of B.
burgdorferi sensu lato complex. One nucleotide difference in the size of 5S-23S
intergenic spacer region, 1 substitution in 16S rRNA gene signature nucleotides,
and silent nucleotide substitutions in sequences of flagellin and p66 genes
clearly separate Borrelia sp. nov. isolates from South Carolina into two
subgroups. The sequences of isolates of each subgroup share the same RFLP
patterns of 5S-23S intergenic spacer region and contain unique signature
nucleotides in the 16S rRNA gene. We propose that seven Borrelia sp. nov.
isolates from South Carolina and two California isolates designated as
genomospecies 1 comprise a single species which we name Borrelia americana sp.
nov. The currently recognized geographic distribution of B. americana is South
Carolina and California. All strains are associated with Ixodes pacificus or
Ixodes minor and their rodent and bird hosts.

http://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&id=19846628&retmode=ref&cmd=prlinks
PMID: 19846628  [PubMed – as supplied by publisher]