CD11c+ cells acquire Plasmodium from hepatocytes to prime CD8 T cell immunity to liver-stage malaria

Malaria, caused by Plasmodium parasites is responsible for the illness of millions of individuals each year. Plasmodium sporozoites inoculated by mosquitoes migrate to the liver and infect hepatocytes prior to release of merozoites that initiate symptomatic blood-stage malaria. Parasites are thought to be restricted to hepatocytes throughout this obligate liver-stage of replication and differentiation. In contrast to this notion, we found that a subset of hepatic CD11c+ cells co-expressing F4/80, CD103, CD207 and CSF1R, acquired a substantial parasite burden during the liver-stage of malaria, but only after initial hepatocyte infection. These CD11c+ cells found in the infected liver and liver-draining lymph nodes exhibited transcriptionally and phenotypically enhanced antigen-presentation functions; and primed protective CD8 T cell responses against Plasmodium liver-stage restricted antigens. Our findings uncover a novel aspect of Plasmodium biology as well as the fundamental mechanism by which CD8 T cell responses are primed against liver-stage malaria.

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