A malaria heat-shock-like determinant expressed on the infected hepatocyte surface is the target of antibody-dependent cell-mediated cytotoxic mechanisms by nonparenchymal liver cells.

Cultured hepatic stages of Plasmodium falciparum and P. yoelii and with a monoclonal antibody recognizing a C-terminal fragment of the P. falciparum heat-shock-like protein (Pfhsp70) revealed that synthesis of this antigen first occurs during intrahepatic development of the parasite, at the two nuclei stage. Using a variety of techniques, including scanning electron microscopy, we observed that this antigenic determinant was expressed on the infected hepatocyte membrane. Its participation in antibody-dependent cell-mediated cytotoxicity was investigated. While no effect was obtained with peripheral blood cells, we found that 25% of the schizonts were specifically lysed when using spleen cells at a killer/target ratio of 30/1. More interestingly, with nonparenchymal liver cells, up to 50% of the hepatic parasites disappeared with a killer/target ratio of 10/1.