AUTHOR=Nakamae Sayuri , Miyagawa Satoshi , Ogawa Koki , Kamiya Mariko , Taniguchi Mayumi , Ono Akari , Kawaguchi Maho , Teklemichael Awet Alem , Jian Jiun-Yu , Araki Tamasa , Katagami Yukimi , Mukai Hidefumi , Annoura Takeshi , Yui Katsuyuki , Hirayama Kenji , Kawakami Shigeru , Mizukami Shusaku TITLE=Induction of liver-resident memory T cells and protection at liver-stage malaria by mRNA-containing lipid nanoparticles JOURNAL=Frontiers in Immunology VOLUME=14 YEAR=2023 URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2023.1116299 DOI=10.3389/fimmu.2023.1116299 ISSN=1664-3224 ABSTRACT=

Recent studies have suggested that CD8+ liver-resident memory T (TRM) cells are crucial in the protection against liver-stage malaria. We used liver-directed mRNA-containing lipid nanoparticles (mRNA-LNPs) to induce liver TRM cells in a murine model. Single-dose intravenous injections of ovalbumin mRNA-LNPs effectively induced antigen-specific cytotoxic T lymphocytes in a dose-dependent manner in the liver on day 7. TRM cells (CD8+ CD44hi CD62Llo CD69+ KLRG1-) were induced 5 weeks after immunization. To examine the protective efficacy, mice were intramuscularly immunized with two doses of circumsporozoite protein mRNA-LNPs at 3-week intervals and challenged with sporozoites of Plasmodium berghei ANKA. Sterile immunity was observed in some of the mice, and the other mice showed a delay in blood-stage development when compared with the control mice. mRNA-LNPs therefore induce memory CD8+ T cells that can protect against sporozoites during liver-stage malaria and may provide a basis for vaccines against the disease.