Functional Analysis of the Borrelia burgdorferi bb... [PLoS One. 2011] - PubMed result

PLoS One. 2011 May 3;6(5):e19536.
Functional Analysis of the Borrelia burgdorferi bba64 Gene Product in Murine Infection via Tick Infestation.
Patton TG, Dietrich G, Dolan MC, Piesman J, Carroll JA, Gilmore RD Jr.

Source
Microbiology and Pathogenesis Activity, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, United States of America.


Abstract
Borrelia burgdorferi, the causative agent of Lyme borreliosis, is transmitted to humans from the bite of Ixodes spp. ticks. During the borrelial tick-to-mammal life cycle, B. burgdorferi must adapt to many environmental changes by regulating several genes, including bba64. Our laboratory recently demonstrated that the bba64 gene product is necessary for mouse infectivity when B. burgdorferi is transmitted by an infected tick bite, but not via needle inoculation. In this study we investigated the phenotypic properties of a bba64 mutant strain, including 1) replication during tick engorgement, 2) migration into the nymphal salivary glands, 3) host transmission, and 4) susceptibility to the MyD88-dependent innate immune response. Results revealed that the bba64 mutant's attenuated infectivity by tick bite was not due to a growth defect inside an actively feeding nymphal tick, or failure to invade the salivary glands. These findings suggested there was either a lack of spirochete transmission to the host dermis or increased susceptibility to the host's innate immune response. Further experiments showed the bba64 mutant was not culturable from mouse skin taken at the nymphal bite site and was unable to establish infection in MyD88-deficient mice via tick infestation. Collectively, the results of this study indicate that BBA64 functions at the salivary gland-to-host delivery interface of vector transmission and is not involved in resistance to MyD88-mediated innate immunity.

PMID:21559293[PubMed - in process] PMCID: PMC3086921
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Functional Analysis of the Borrelia burgdorferi bba64 Gene Product in Murine Infection via Tick Infestation

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Figure 1bba64 and ospC expression during nymphal tick feeding.Fold change in A) bba64 and B) ospC expression in actively feeding and replete WT-infected nymphs relative to flat nymphs. Data represents the average of 4 independent experiment samples per time point (each technically replicated in triplicate), and error bars correspond to the standard error of the means (...Functional Analysis of the Borrelia burgdorferi bba64 Gene Product in Murine Infection via Tick InfestationPLoS One. 2011;6(5):e19536.Figure 2qPCR-based enumeration of B. burgdorferi in individual actively feeding nymphal ticks.WT- (white bars) or bba64 mutant- (black bars) infected nymphs were fed on mice and removed at 33 h, 48 h, 57 h, and 72 h. Flat (0 h) and replete infected nymphs were also collected. Borrelia were enumerated by qPCR using flaB Taqman probe and primers. The data represents the average of 5 individually crushed nymphs...Functional Analysis of the Borrelia burgdorferi bba64 Gene Product in Murine Infection via Tick InfestationPLoS One. 2011;6(5):e19536.

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Functional Analysis of the Borrelia burgdorferi bb... [PLoS One. 2011] - PubMed result