Plasmodium spp., the causative agent of malaria, have a complex life cycle. The exponential growth of the parasites during the blood stage is responsible for almost all malaria-associated morbidity and mortality. Therefore, tight immune control of the intraerythrocytic replication of the parasite is essential to prevent clinical malaria. Despite evidence that the particular lymphocyte subset of γδ T cells contributes to protective immunity during the blood stage in naive hosts, their precise inhibitory mechanisms remain unclear.
Starting from a bipyridine-sulfonamide scaffold, medicinal chemistry optimization leads to the discovery of a novel Plasmodium falciparum PI4K kinase (PfPI4K) inhibitor compound 15g (CHMFL-PI4K-127, IC50: 0.9 nM), which exhibits potent activity against 3D7 Plasmodium falciparum (P. falciparum) (EC50: 25.1 nM). CHMFL-PI4K-127 displays high selectivity against PfPI4K over human lipid and protein kinase.
Although the spleen is broadly accepted as the major lymphoid organ involved in generating immune responses to the erythrocytic stages of the malaria parasite, Plasmodium, human splenic tissue is not readily available in most cases.