Fractalkine-conjugated mRNA LNPs induce expression of homing molecules in cytotoxic effector CD8+ T cells 4515

Abstract Description Cytotoxic effector CD8+ T (Teff) cells are powerful immune cells that kill virally infected or cancerous cells. However, as Teff cells lack expression of the homing molecule CD62L and are confined to the vasculature, they usually do not circulate through or exert cytotoxicity on cells in lymph nodes or other secondary lymphoid tissues. Previous studies have shown that murine Teff cells transgenic for a shedding-deficient CD62L maintained homing ability into tissues independent of differentiation state, highlighting CD62L’s ability to enable trafficking. As such, we hypothesized that re-expression of CD62L in human Teff cells would enable their trafficking into lymphoid tissues, substantially broadening their usage in cell-based therapies. However, there have not been any published methods to express CD62L in human Teff cells. We recently showed that fractalkine-conjugated GFP mRNA LNPs can target human Teff cells in vitro and murine and rhesus macaque Teff cells in vivo. Using the same platform, we created fractalkine-conjugated mRNA LNPs encoding shedding-deficient human CD62L and found that these LNPs successfully induce robust expression of CD62L in human, rhesus macaque, and cynomolgus Teff cells. In addition, the expression of CD62L occurs rapidly and in a dose dependent manner. Collectively our data indicate that fractalkine-conjugated CD62L-encoding mRNA LNPs can drive CD62L expression in Teff cells and provide a novel platform to reprogram their in vivo trafficking. Funding Sources NIH UM1AI169633, Penn internal funds, ERASE-HIV UM1 AI164562 Topic Categories Cellular Adhesion, Migration, and Inflammation (CAM)