Mariana Borsa, Ana Victoria Lechuga‐Vieco, Amir Hossein Kayvanjoo, Edward Jenkins, Yavuz F. Yazicioglu, Ewoud B. Compeer, Felix Clemens Richter, Simon Rapp, Robert J. Mitchell, Tom Youdale, Hien Bui, Emilia Kuuluvainen, Michael L. Dustin, Linda V. Sinclair, Pekka Katajisto, Anna Katharina Simon
Abstract T cell immunity deteriorates with age, accompanied by a decline in autophagy and asymmetric cell division. Here we show that autophagy regulates mitochondrial inheritance in CD8 + T cells. Using a mouse model that enables sequential tagging of mitochondria in mother and daughter cells, we demonstrate that autophagy-deficient T cells fail to clear premitotic old mitochondria and inherit them symmetrically. By contrast, autophagy-competent cells that partition mitochondria asymmetrically produce daughter cells with distinct fates: those retaining old mitochondria exhibit reduced memory potential, whereas those that have not inherited old mitochondria and exhibit higher mitochondrial turnover are long-lived and expand upon cognate-antigen challenge. Multiomics analyses suggest that early fate divergence is driven by distinct metabolic programmes, with one-carbon metabolism activated in cells retaining premitotic mitochondria. These findings advance our understanding of how T cell diversity is imprinted early during division and support the development of strategies to modulate T cell function.