Evaluation of immunity against malaria using luciferase-expressing Plasmodium berghei parasites

BACKGROUND: Measurement of liver stage development is of key interest in malaria biology and vaccine studies. Parasite development in liver cells can be visualized in real-time, both in culture and in live mice, using a transgenic Plasmodium berghei parasite, PbGFP-Luc(con), expressing the bioluminescent reporter luciferase. This study explores the benefit of using these parasites for the evaluation of immunity against malaria, compared to qRT-PCR techniques in vivo and in vitro. METHODS: Mice were immunized with either radiation attenuated sporozoites (RAS) or wildtype sporozoites under chloroquine prophylaxis (CPS) and challenged with PbGFP-Luc(con. )The in vitro transgenic sporozoites neutralization assay (TSNA) was adapted by replacing PbCS(Pf) parasites for PbGFP-Luc(con )parasites. RESULTS: Application of PbGFP-Luc(con )transgenic parasites provides live quantitative visual information about the relation between parasite liver load and protection. Moreover, fast and reproducible results are obtained by using these parasites in the transgenic sporozoites neutralization assay, measuring functional antibody-mediated immune responses. CONCLUSIONS: PbGFP-Luc(con )parasites are a straightforward and valuable tool for comprehension of the biological and immunological principles underlying protection against malaria.