You Shall Not Pass: Memory CD8 T Cells in Liver-Stage Malaria.

Each year over 200 million malaria infections occur, with over 400 000 associated deaths. Vaccines formed with attenuated whole parasites can induce protective memory CD8 T cell responses against liver-stage malaria; however, widespread administration of such vaccines is logistically challenging. Recent scientific findings are delineating how protective memory CD8 T cell populations are primed and maintained and how such cells mediate immunity to liver-stage malaria. Memory CD8 T cell anatomic localization and expression of transcription factors, homing receptors, and signaling molecules appear to play integral roles in protective immunity to liver-stage malaria. Further investigation of how such factors contribute to optimal protective memory CD8 T cell generation and maintenance in humans will inform efforts for improved vaccines. Novel discoveries about the role of memory CD8 T cells in mediating immunity to liver-stage malaria are informing methods of resolving historical issues of malaria vaccine efficacy and implementation. Liver resident memory (Trm) cells are essential to mediate sterilizing immunity against liver-stage malaria after whole-parasite immunization in mouse models. Circulating memory CD8 T cell contributions to protection remain undefined. Mechanisms of liver Trm cell generation, maintenance, and protective function are active areas of investigation. The unique hepatic microenvironment appears to dictate phenotypic characteristics and motility dynamics of local liver Trm cells at homeostasis. [ABSTRACT FROM AUTHOR]