A lactate dehydrogenase ELISA-based assay for the in vitro determination of Plasmodium berghei sensitivity to anti-malarial drugs

• Published in: Malaria Journal
• Main Authors: Orjuela-Sánchez Pamela, Duggan Erika, Nolan John, Frangos John A, Carvalho Leonardo JM
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2012
• Subjects: Plasmodium berghei; In vitro culture; schizont; synchronized infection; drug in vitro assay; anti-malarials; IC 50 values; lactate dehydrogenase; ELISA; Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic
• Online Access: https://doi.org/10.1186/1475-2875-11-366; https://doaj.org/article/dfbe8dab649f44bb8fb1fd37122a000c

Abstract Background Plasmodium berghei rodent malaria is a well-known model for the investigation of anti-malarial drug efficacy in vivo . However, the availability of drug in vitro assays in P. berghei is reduced when compared with the spectrum of techniques existing for Plasmodium falciparum . New alternatives to the current manual or automated methods described for P. berghei are attractive. The present study reports a new ELISA drug in vitro assay for P. berghei using two monoclonal antibodies against the parasite lactate dehydrogenase (pLDH). Methods This procedure includes a short- in vitro culture, the purification of schizonts and the further generation of synchronized mice infections. Early stages of the parasite are then incubated against different concentrations of anti-malarial drugs using micro-plates. The novelty of this procedure in P. berghei relies on the quantification of the drug activity derived from the amount of pLDH estimated by an ELISA assay using two monoclonal antibodies: 14C1 and 19G7. The IC 50 s obtained through the ELISA assay were compared with those from the micro-test. Results The initial parameters of the synchronized samples used in the in vitro assays were a parasitaemia of 0.5% and haematocrit of 1%, with an incubation period of 22 hours at 36.5°C. pLDH detection using a 14C1 coating at 10 μg/ml and 19G7 at 2.5 × 10 -3 μg/ml provided good readouts of optical densities with low background in negative controls and specific detection levels for all parasite stages. IC 50 s values derived from the ELISA assay for artesunate, chloroquine, amodiaquine and quinine were: 15, 7, 2, and 144 nM, respectively. When artesunate and chloroquine IC 50 s were evaluated using the micro-test similar values were obtained. Conclusion This ELISA-based in vitro drug assay is easy to implement, fast, and avoids the use radioisotopes or expensive equipment. The utility of this simple assay for screening anti-malarial drug activity against P. berghei in vitro is demonstrated.