Visualization of opsonic phagocytosis of merozoites by THP-1 cells. (A) Scanning electron microscopy of THP-1 cells before and during ingestion of merozoites. (B) Immunofluorescence microscopy of phagocytosis of merozoites opsonized with purified IgG from malaria-immune adults (MIG). THP-1 cells were visualized by differential interference contrast (DIC), while merozoites were visualized with Hoechst (blue). Figures represent data acquired from at least two independent experiments.