Reuling, Isaie J; Stone, Will JR; van de Vegte-Bolmer, Marga; van Gemert, Geert-Jan; Siebelink-Stoter, Rianne; Graumans, Wouter; Lanke, Kjerstin; Bousema, Teun; Sauerwein, Robert W; (2017) Concentration of Plasmodium falciparum gametocytes in whole blood samples by magnetic cell sorting enhances parasite infection rates in mosquito feeding assays. Malaria journal, 16 (1). 315-. ISSN 1475-2875 DOI: https://doi.org/10.1186/s12936-017-1959-9
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Abstract
BACKGROUND: Mosquito-feeding assays are important tools to guide the development and support the evaluation of transmission-blocking interventions. These functional bioassays measure the sporogonic development of gametocytes in blood-fed mosquitoes. Measuring the infectivity of low gametocyte densities has become increasingly important in malaria elimination scenarios. This will pose challenges to the sensitivity and throughput of existing mosquito-feeding assay protocols. Here, different gametocyte concentration methods of blood samples were explored to optimize conditions for detection of positive mosquito infections. METHODS: Mature gametocytes of Plasmodium falciparum were diluted into whole blood samples of malaria-naïve volunteers. Standard centrifugation, Percoll gradient, magnetic cell sorting (MACS) enrichment were compared using starting blood volumes larger than the control (direct) feed. RESULTS: MACS gametocyte enrichment resulted in the highest infection intensity with statistically significant increases in mean oocyst density in 2 of 3 experiments (p = 0.0003; p ≤ 0.0001; p = 0.2348). The Percoll gradient and standard centrifugation procedures resulted in variable infectivity. A significant increase in the proportion of infected mosquitoes and oocyst density was found when larger volumes of gametocyte-infected blood were used with the MACS procedure. CONCLUSIONS: The current study demonstrates that concentration methods of P. falciparum gametocyte-infected whole blood samples can enhance transmission in mosquito-feeding assays. Gametocyte purification by MACS was the most efficient method, allowing the assessment of gametocyte infectivity in low-density gametocyte infections, as can be expected in natural or experimental conditions.
Item Type | Article |
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Faculty and Department | Faculty of Infectious and Tropical Diseases > Department of Infection Biology |
PubMed ID | 28779750 |
ISI | 407838600002 |
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