English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Background   Plasmodium  18S rRNA is a biomarker used to monitor blood-stage infections in malaria clinical trials.  Plasmodium  sporozoites also express this biomarker, and there is conflicting evidence about how long sporozoite-derived 18S rRNA persists in peripheral blood. If present in blood for an extended timeframe, sporozoite-derived 18S rRNA could complicate use as a blood-stage biomarker.    Methods  Blood samples from  Plasmodium yoelii  infected mice were tested for  Plasmodium  18S rRNA and their coding genes (rDNA) using sensitive quantitative reverse transcription PCR and quantitative PCR assays, respectively. Blood and tissues from  Plasmodium falciparum  sporozoite (PfSPZ)-infected rhesus macaques were similarly tested.    Results  In mice, when  P. yoelii  sporozoite inoculation and blood collection were performed at the same site (tail vein), low level rDNA positivity persisted for 2 days post-infection. Compared to intact parasites with high rRNA-to-rDNA ratios, this low level positivity was accompanied by no increase in rRNA-to-rDNA, indicating detection of residual, non-viable parasite rDNA. When  P. yoelii  sporozoites were administered via the retro-orbital vein and blood sampled by cardiac puncture, neither  P. yoelii  18S rRNA nor rDNA were detected 24 h post-infection. Similarly, there was no  P. falciparum  18S rRNA detected in blood of rhesus macaques 3 days after intravenous injection with extremely high doses of PfSPZ.  Plasmodium  18S rRNA in the rhesus livers increased by approximately 101-fold from 3 to 6 days post infection, indicating liver-stage proliferation.    Conclusions  Beyond the first few hours after injection, sporozoite-derived  Plasmodium  18S rRNA was not detected in peripheral blood. Diagnostics based on 18S rRNA are unlikely to be confounded by sporozoite inocula in human clinical trials.

Plasmodium 18S rRNA of intravenously administered sporozoites does not persist in peripheral blood