title: Enhancing longevity of Plasmodium vivax and P. falciparum sporozoites after dissection from mosquito salivary glands.
abstract: The pre-erythrocytic stages of Plasmodium vivax and Plasmodium falciparum remain challenging for experimental research in part due to limited access to sporozoites. An important factor limiting availability is the laboratory support required for producing infected mosquitoes and the ephemeral nature of isolated extracellular sporozoites. This study was undertaken to investigate methods to improve the availability of this limited resource by extending the longevity of the extracellular sporozoites after mosquito dissection. Our goal in this study was to determine whether buffer conditions more closely mimicking the insect microenvironment could prolong longevity of ex vivo P. vivax and P. falciparum sporozoites. The study compared the current standard dissection buffer RPMI1640 to Hank's Balanced Salt Solution with 1g/L glucose (HBSS-1) or 2g/L glucose (HBSS-2) and Grace's Insect Medium for ability to extend longevity of ex vivo P. vivax and P. falciparum sporozoites. The effect of each buffer on sporozoite viability was evaluated by measuring sporozoite gliding motility at 0, 4, 8, and 24h post-dissection from mosquito salivary glands. Comparisons of mean gliding percentages of ex vivo sporozoites in the different buffers and time points found that RPMI and Grace's both showed strong gliding at 0h. In contrast, by 4h post-dissection sporozoites in RPMI consistently had the lowest gliding activity, whereas sporozoites in Grace's had significantly more gliding compared to all other buffers at almost all time points. Our results indicate that P. vivax and P. falciparum sporozoites maintained in insect media rather than the standard dissection buffer RPMI and HBSS retain viability better over time.
authors.affiliation: Department of Global Health, College of Public Health, University of South Florida, Tampa, FL, USA.
authors.forename: Emily J
authors.initials: EJ
authors.lastname: Lupton
authors.affiliation: Department of Global Health, College of Public Health, University of South Florida, Tampa, FL, USA.
authors.forename: Alison
authors.initials: A
authors.lastname: Roth
authors.affiliation: Mahidol Vivax Research Unit, Mahidol University, Bangkok 10400, Thailand.
authors.forename: Rapatbhorn
authors.initials: R
authors.lastname: Patrapuvich
authors.affiliation: Department of Global Health, College of Public Health, University of South Florida, Tampa, FL, USA.
authors.forename: Steve P
authors.initials: SP
authors.lastname: Maher
authors.affiliation: Department of Global Health, College of Public Health, University of South Florida, Tampa, FL, USA.
authors.forename: Naresh
authors.initials: N
authors.lastname: Singh
authors.affiliation: Mahidol Vivax Research Unit, Mahidol University, Bangkok 10400, Thailand.
authors.forename: Jetsumon
authors.initials: J
authors.lastname: Sattabongkot
authors.affiliation: Department of Global Health, College of Public Health, University of South Florida, Tampa, FL, USA. Electronic address: jadams3@health.usf.edu.
authors.forename: John H
authors.initials: JH
authors.lastname: Adams
mesh_terms: D000818:Animals; D000852:Anopheles / Q000469:parasitology*; D018929:Cell Culture Techniques; D019976:Cloning, Organism; D003470:Culture Media; D010963:Plasmodium falciparum / Q000502:physiology*; D010966:Plasmodium vivax / Q000502:physiology*; D012469:Salivary Glands / Q000469:parasitology*; D034101:Sporozoites / Q000502:physiology*; D013997:Time Factors
chemical_list: D003470:Culture Media
keywords: Assays; Malaria; Plasmodium; Sporozoite; Viability