UNASSIGNED: @entity311 symptoms and pathogenesis are caused by blood stage parasite burdens of @entity3964 spp., for which invasion of red blood cells (RBCs) by merozoites is essential. Successful targeting by either drugs or vaccines directed against the whole merozoite or its antigens during its transient extracellular status would contribute to @entity311 control by impeding RBC invasion. To understand merozoite invasion biology and mechanisms, it is desired to obtain merozoites that retain their invasion activity in vitro. Accordingly, methods have been developed to isolate invasive @entity31365 and @entity3964 merozoites. Rodent @entity311 parasite models offer ease in laboratory maintenance and experimental genetic modifications; however, no methods have been reported regarding isolation of high numbers of @entity3 merozoites. In this study, @entity501 -infected RBCs were obtained from infected @entity19 , and mature schizont-infected RBCs enriched via Histodenz    density gradients. Merozoites retaining invasion activity were then isolated by passing the preparations through a filter membrane. RBC-invaded parasites developed to mature stages in vitro in a synchronous manner. Isolated merozoites were evaluated for retention of invasion activity following storage at different temperatures prior to incubation with uninfected @entity19 RBCs. Isolated merozoites retained their invasion activity 4h after isolation at 10 or 15  C, whereas their invasion activity reduced to 0-10% within 30min when incubated on ice or at 37  C prior to RBC invasion assay. Images of merozoites at successive steps during RBC invasion were captured by light and transmission electron microscopy. Synthetic peptides derived from the @entity3689 sequence of the @entity501 invasion protein RON2 efficiently inhibited RBC invasion. The developed method to isolate and keep invasive @entity501 merozoites for up to 4h is a powerful tool to study the RBC invasion biology of this parasite. This method provides an important platform to evaluate the mode of action of drugs and vaccine candidates targeting the RBC invasion steps using rodent @entity311 model.

Isolation of invasive XXXX merozoites with a long half-life to evaluate invasion dynamics and potential invasion inhibitors.

@entity19 :: ('10090', 'Species') :: ['mice', 'mouse'] @entity3964 :: ('5833', 'Species') :: ['Plasmodium falciparum', 'Plasmodium'] @entity501 :: ('5861', 'Species') :: ['Plasmodium yoelii', 'P. yoelii'] @entity3 :: ('MESH:D009362', 'Disease') :: ['invasive rodent malaria'] @entity311 :: ('MESH:D008288', 'Disease') :: ['Malaria', 'malaria'] @entity31365 :: ('5850', 'Species') :: ['Plasmodium knowlesi'] @entity3689 :: ('D000596', 'Chemical') :: ['amino acid']
@entity501 :: (5861,Species) :: ['Plasmodium yoelii']
