Malaria is a major health problem worldwide, and its significance may be on the increase due to the rapid spread of parasite strains that are resistant to conventional anti-malaria drugs. Evidence suggests that during the inital phase of infection (liver-stage) the Plasmodium parasites may be susceptible to neutralization by drugs or vaccines. The infection of liver cells by plasmodium can be studied in vitro, using human hepatoma cell lines. This system could be used as a model to screen for neutralizing activity. However, this approach is hampered by the lack of a rapid quantitative assay for the number of plasmodium parasites that are present in a hepatoma cell culture. We propose to develop a novel sandwich ELISA assay that will facilitate the rapid high-throughput screening of anti-malaria drugs. To this end, we will first raise novel rabbit monoclonal antibodies to several major proteins that are present in liver-stage plasmodium parasites. We will use our proprietary rabbit hybridoma technology to develop antibodies to both synthetic peptides and recombinant proteins based on Plasmodium sequences. Pairs of antibodies recognizing independent epitopes on a given protein will be rapidly identified by using a novel sandwich screening approach. This research is designed to develop a rapid ELISA assay for quantifying malaria parasites present in infected liver cells. This novel assay will be substantailly more sensitive, specific, reliable, and easier to use than currently available assays. It will provide significant advantages to researchers developing novel approaches for the treatment of liver-stage malaria. On the basis of our novel assay, we will develop a test kit that will be marketed to research institutes, hospitals, and companies interested in quantifying infection by liver-stage plasmodium parasites. Furthermore, the novel monoclonal antibodies developed in the course of this project may have additional applications in malaria research and/or drug development
