The Standard Membrane Feeding Assay: Advances Using Bioluminescence.

Abstract

In preclinical development, the efficacy of agents with putative effects on Plasmodium transmission is determined using the standard membrane feeding assay (SMFA). Because the end-point of the SMFA is normally the enumeration of oocysts on the mosquito midgut, the assays reliance on mosquito dissections and microscopy makes it slow, labor-intensive, and subjective. Below, we describe a novel method of assessing the transmission of a Plasmodium falciparum strain expressing the firefly luciferase protein in the SMFA. The use of a transgenic parasite strain allows for the elimination of mosquito dissections in favor of a simple approach where whole mosquitoes are homogenized and examined directly for luciferase activity. Measuring the mean luminescence intensity of groups of individual or pooled mosquitoes provides comparable estimates of transmission reducing activity at 5-10-fold the throughput capacity of the standard microscopy based SMFA. This high efficiency protocol may be of interest to groups screening novel drug compounds, vaccine candidates, or sera from malaria exposed individuals for transmission reducing activity (TRA).