Schlabe, Stefan;
Korir, Patricia;
Lämmer, Christine;
Landmann, Frederic;
Dubben, Bettina;
Koschel, Marianne;
Albers, Anna;
Debrah, Linda Batsa;
Debrah, Alexander Yaw;
Hübner, Marc P.;
Pfarr, Kenneth;
Klarmann-Schulz, Ute;
Hoerauf, Achim
A qPCR to quantify Wolbachia from few Onchocerca volvulus microfilariae as a surrogate for adult worm histology in clinical trials of antiwolbachial drugs
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Media type:
E-Article
Title:
A qPCR to quantify Wolbachia from few Onchocerca volvulus microfilariae as a surrogate for adult worm histology in clinical trials of antiwolbachial drugs
Contributor:
Schlabe, Stefan;
Korir, Patricia;
Lämmer, Christine;
Landmann, Frederic;
Dubben, Bettina;
Koschel, Marianne;
Albers, Anna;
Debrah, Linda Batsa;
Debrah, Alexander Yaw;
Hübner, Marc P.;
Pfarr, Kenneth;
Klarmann-Schulz, Ute;
Hoerauf, Achim
imprint:
Springer Science and Business Media LLC, 2022
Description:
<jats:title>Abstract
</jats:title><jats:p>The filarial nematode <jats:italic>Onchocerca volvulus</jats:italic> causes onchocerciasis (river blindness), a neglected tropical disease affecting 21 million people, mostly in Sub-Saharan Africa. Targeting the endosymbiont <jats:italic>Wolbachia</jats:italic> with antibiotics leads to permanent sterilization and killing of adult worms. The gold standard to assess <jats:italic>Wolbachia</jats:italic> depletion is the histological examination of adult worms in nodules beginning at 6 months post-treatment. However, nodules can only be used once, limiting the time points to monitor <jats:italic>Wolbachia</jats:italic> depletion. A diagnostic to longitudinally monitor <jats:italic>Wolbachia</jats:italic> depletion from microfilariae (MF) at more frequent intervals < 6 months post-treatment would accelerate clinical trials of antiwolbachials. We developed a TaqMan qPCR amplifying the single-copy gene <jats:italic>w</jats:italic>Ov<jats:italic>ftsZ</jats:italic> to quantify <jats:italic>Wolbachia</jats:italic> from as few as one MF that had migrated from skin biopsies and compared quantification using circular and linearized plasmids or synthetic dsDNA (gBlock®). qPCR for MF from the rodent nematode <jats:italic>Litomosoides sigmodontis</jats:italic> was used to support the reproducibility and validate the principle. The qPCR using as few as 2 MF from <jats:italic>O. volvulus</jats:italic> and <jats:italic>L. sigmodontis</jats:italic> reproducibly quantified <jats:italic>Wolbachia</jats:italic>. Use of a linearized plasmid standard or synthesized dsDNA resulted in numbers of <jats:italic>Wolbachia</jats:italic>/MF congruent with biologically plausible estimates in <jats:italic>O. volvulus</jats:italic> and <jats:italic>L. sigmodontis</jats:italic> MF. The qPCR assay yielded a median of 48.8 (range 1.5–280.5) <jats:italic>Wolbachia</jats:italic>/<jats:italic>O. volvulus</jats:italic> MF. The qPCR is a sensitive tool for quantifying <jats:italic>Wolbachia</jats:italic> in a few MF from skin biopsies and allows for establishing the qPCR as a surrogate parameter for monitoring <jats:italic>Wolbachia</jats:italic> depletion in adult worms of new antiwolbachial candidates.</jats:p>