Sophie Jones

Publications (7) View all

• Article: Filter paper collection of Plasmodium falciparum mRNA for detecting low-density gametocytes.

  Sophie Jones, Colin J Sutherland, Cornelus Hermsen, Theo Arens, Karina Teelen, Rachel Hallett, Patrick Corran, Marga van der Vegte-Bolmer, Robert Sauerwein, Chris J Drakeley, Teun Bousema
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  ABSTRACT: Accurate sampling of sub-microscopic gametocytes is necessary for epidemiological studies to identify the infectious reservoir of Plasmodium falciparum. Detection of gametocyte mRNA achieves sensitive detection, but requires careful handling of samples. Filter papers can be used for collecting RNA samples, but rigorous testing of their capacity to withstand adverse storage conditions has not been fully explored. Three gametocyte dilutions: 10/μL, 1.0/μL and 0.1/μL were spotted onto Whatman™ 903 Protein Saver Cards, FTA Classic Cards and 3MM filter papers that were stored under frozen, cold chain or tropical conditions for up to 13 weeks . RNA was extracted, then detected by quantitative nucleic acid sequence-based amplification (QT-NASBA) and reverse-transcriptase PCR (RT-PCR). Successful gametocyte detection was more frequently observed from the Whatman 903 Protein Saver Card compared to the Whatman FTA Classic Card, by both techniques (p < 0.0001). When papers were stored at higher temperatures, a loss in sensitivity was experienced for the FTA Classic Card but not the 903 Protein Saver Card or Whatman 3MM filter paper. The sensitivity of gametocyte detection was decreased when papers were stored at high humidity. This study indicates the Whatman 903 Protein Saver Card is better for Pfs25 mRNA sampling compared to the Whatman FTA Classic Card, and that the Whatman 3MM filter paper may prove to be a satisfactory cheaper option for Pfs25 mRNA sampling. When appropriately dried, filter papers provide a useful approach to Pfs25 mRNA sampling, especially in settings where storage in RNA-protecting buffer is not possible.
  Malaria Journal 08/2012; 11:266. · 3.19 Impact Factor
• Source

  Available from: Raffaele Ronca

  Article: IgG responses to Anopheles gambiae salivary antigen gSG6 detect variation in exposure to malaria vectors and disease risk.

  Will Stone, Teun Bousema, Sophie Jones, Samwel Gesase, Rhamadhan Hashim, Roly Gosling, Ilona Carneiro, Daniel Chandramohan, Thor Theander, Raffaele Ronca, David Modiano, Bruno Arcà, Chris Drakeley
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  ABSTRACT: Assessment of exposure to malaria vectors is important to our understanding of spatial and temporal variations in disease transmission and facilitates the targeting and evaluation of control efforts. Recently, an immunogenic Anopheles gambiae salivary protein (gSG6) was identified and proposed as the basis of an immuno-assay determining exposure to Afrotropical malaria vectors. In the present study, IgG responses to gSG6 and 6 malaria antigens (CSP, AMA-1, MSP-1, MSP-3, GLURP R1, and GLURP R2) were compared to Anopheles exposure and malaria incidence in a cohort of children from Korogwe district, Tanzania, an area of moderate and heterogeneous malaria transmission. Anti-gSG6 responses above the threshold for seropositivity were detected in 15% (96/636) of the children, and were positively associated with geographical variations in Anopheles exposure (OR 1.25, CI 1.01-1.54, p = 0.04). Additionally, IgG responses to gSG6 in individual children showed a strong positive association with household level mosquito exposure. IgG levels for all antigens except AMA-1 were associated with the frequency of malaria episodes following sampling. gSG6 seropositivity was strongly positively associated with subsequent malaria incidence (test for trend p = 0.004), comparable to malaria antigens MSP-1 and GLURP R2. Our results show that the gSG6 assay is sensitive to micro-epidemiological variations in exposure to Anopheles mosquitoes, and provides a correlate of malaria risk that is unrelated to immune protection. While the technique requires further evaluation in a range of malaria endemic settings, our findings suggest that the gSG6 assay may have a role in the evaluation and planning of targeted and preventative anti-malaria interventions.
  PLoS ONE 01/2012; 7(6):e40170. · 4.09 Impact Factor
• Article: Population-based analysis of Actinobacillus pleuropneumoniae ApxIVA for use as a DIVA antigen.

  Ciaragh O'Neill, Sophie C P Jones, Janine T Bossé, Conrad M Watson, Susanna M Williamson, Andrew N Rycroft, J Simon Kroll, Helen M Hartley, Paul R Langford
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  ABSTRACT: APXIVA is an RTX toxin of Actinobacillus pleuropneumoniae that is a candidate antigen to differentiate infected from vaccinated animals (DIVA). Insertion of ISApl1 into the apxIVA gene is known to compromise an APXIVA-based DIVA approach, as is potentially a TGG to TGA mutation in the apxIVA gene. ISApl1 was found in 63/349 (18.1%) A. pleuropneumoniae isolates from England and Wales including serovars 2, 3, 6-8 and 12. No ISApl1 insertions into apxIVA were found. Only two serovar 3 isolates contained the TGG to TGA mutation. We conclude that an ApxIVA-based DIVA approach would potentially be viable in England and Wales.
  Vaccine 07/2010; 28(31):4871-4. · 3.77 Impact Factor
• Article: Prevalence of Actinobacillus pleuropneumoniae serovars in England and Wales.

  C O'Neill, S C P Jones, J T Bossé, C M Watson, S M Williamson, A N Rycroft, J S Kroll, H M Hartley, P R Langford
  The Veterinary record. 10/2010; 167(17):661-2.
• Source

  Available from: Nina Baltes

  Article: ISApl1, a novel insertion element of Actinobacillus pleuropneumoniae, prevents ApxIV-based serological detection of serotype 7 strain AP76.

  Halina E Tegetmeyer, Sophie C P Jones, Paul R Langford, Nina Baltes
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  ABSTRACT: Actinobacillus pleuropneumoniae, a gram-negative rod of the Pasteurellaceae family, causes pleuropneumonia in pigs. Establishing A. pleuropneumoniae free herds is difficult due to the occurrence of persistently infected animals. The ApxIV toxin is expressed by A. pleuropneumoniae in vivo and an ELISA based on the toxin is used to detect infection and to differentiate between infected and vaccinated animals. In this study, we have identified a 1070bp insertion element of the IS30 family, designated ISApl1, in the A. pleuropneumoniae serotype 7 strain AP76. ISApl1 contains a 924bp ORF encoding a transposase, which is flanked by 27bp inverted repeats showing six mismatches. We investigated the occurrence of ISApl1 in other A. pleuropneumoniae strains, and its possible interference with virulence associated factors. Four insertion sites were identified in AP76: within the apxIVA toxin ORF, within a putative autotransporter adhesin ORF, upstream of a capsular polysaccharide biosynthesis gene cluster, and downstream of a beta-lactamase gene. ISApl1 is also present in some serotype 7 field isolates, but not in reference or field strains of other serotypes. In A. pleuropneumoniae AP76, the transposase gene is transcribed in vitro. The insertion in the apxIVA toxin gene remains stable after animal passage. Since this insertion should disrupt toxin expression, we tested 7 pigs infected with AP76 at day 21 post-infection. All were negative in the ApxIV ELISA but four out of seven were positive in an ApxII toxin ELISA. These results show that insertion elements can affect the detection of A. pleuropneumoniae infected animals.
  Veterinary Microbiology 05/2008; 128(3-4):342-53. · 3.33 Impact Factor