The rodent malaria lactate dehydrogenase assay provides a high throughput solution for in vivo vaccine studies. Issue 4 (August 2015)

• Record Type: Journal Article
• Authors: Otsuki, Hitoshi; Yokouchi, Yuki; Iyoku, Natsumi; Tachibana, Mayumi; Tsuboi, Takafumi; Torii, Motomi
• Is Part Of: Parasitology international. Volume 64:Issue 4(2015:Aug.)
• Page Start: 60
• Page End: 63
• Publication Date: 2015-08
• Subjects: Parasitology -- Periodicals; Parasites -- Periodicals; Parasitic Diseases -- Periodicals; Parasitology -- Periodicals; Parasitologie -- Périodiques; 571.99905
• DOI: 10.1016/j.parint.2015.02.001
• Languages: English
• ISSNs: 1383-5769

Abstract

<abstract abstract-type="author" id="ab0005"> <title id="st0005">Abstract</title> <sec> <p id="sp0005">Rodent malaria is a useful model for evaluating the efficacy of malaria vaccine candidates; however, labor-intensive microscopic parasite counting hampers the use of an <italic>in vivo</italic> parasite challenge in high-throughput screening. The measurement of malaria parasite lactate dehydrogenase (pLDH) activity, which is commonly used in the <italic>in vitro</italic> growth inhibition assay of <italic>Plasmodium falciparum</italic>, may be the cheapest and simplest alternative to microscopic parasite counting. However, the pLDH assay has not been applied in the <italic>in vivo</italic> rodent malaria model. Here, we showed that the pLDH assay is reliable and accurately determines parasitemia in the rodent malaria model. pLDH activity measured using a chromogenic substrate reflects the parasite number in the blood; it allows fast and easy assessment using a conventional microplate reader. To validate this approach, we synthesized recombinant PyMSP1-19 protein (rPyMSP1-19) using a wheat germ cell-free protein synthesis system and immunized mice with rPyMSP1-19. The antisera showed specific reactivity on the surface of the <italic>Plasmodium yoelii</italic> merozoite and immunized mice were protected against a lethal <italic>P. yoelii</italic> 17 XL challenge. The pLDH assay quickly and easily demonstrated a significant reduction of the parasite numbers in the immunized mice. Accordingly, the pLDH assay proved to be an efficient alternative to rodent malaria parasite counting, and may therefore accelerate <italic>in vivo</italic> vaccine candidate screening.</p> </sec> </abstract>