OspC facilitates Borrelia burgdorferi invasion of Ixodes scapularis salivary glands
J. Clin. Invest. Utpal Pal, et al. 113:220 doi:10.1172/JCI19894 [
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Figure 3OspC F(ab)
2 fragments interfere with the invasion of
B. burgdorferi to the
I. scapularis salivary glands. (
a) Distribution of
B. burgdorferi within the
I. scapularis salivary glands (top row) or gut (bottom row) 72 hours after the onset of feeding.
B. burgdorferi–infested nymphal ticks were fed on mice that had been treated with F(ab)
2 fragments prepared from either normal rabbit sera (NRS-Fab) or polyclonal OspC sera (OspC-Fab). The spirochetes (arrows) were stained with a FITC-labeled goat anti–
B. burgdorferi (shown in green), and the nuclei of the gut epithelial cells were stained with propidium iodide (shown in red). Due to the lower abundance of spirochetes in the salivary gland than in gut, only a few spirochetes can be visualized through a single focal plane of the microscope. Images were recorded at ×400 magnification and are presented as a merged images for clarity (
n = 3). (
b) Detection of
B. burgdorferi mRNA within engorged
I. scapularis salivary glands or gut. Nymphs treated with NRS-Fab or OspC-Fab were analyzed by RT-PCR for the detection of viable
B. burgdorferi at 48 or 96 hours after the onset of feeding. Equal amounts of total RNA from ticks that fed on F(ab)
2-treated mice were converted to cDNA with reverse transcriptase, subjected to PCR with
flaB primers, and analyzed on a 1.5% agarose gel.
I. scapularis β-actin was used as a control to confirm equal loading of total RNA isolated from infected, fed ticks. An aliquot of prepared RNA from each group was subjected to RT-PCR in the absence of reverse transcriptase to confirm the absence of genomic DNA (data not shown).
