A centrally positioned cluster of multiple centrioles in antigen-presenting cells fosters T cell activation.

Cellular polarization plays a crucial role in regulating immunological processes and is often associated with reorientation of the centrosome. During immune synapse formation, centrosome repositioning in lymphocytes assists in T cell activation. While a single centrosome, consisting of two centrioles, is present in T cells, antigen-presenting cells such as dendritic cells amplify centrioles during maturation and immune activation. How centriole amplification in antigen-presenting cells affects immune synapse formation and T cell activation is unclear. In this study, we combine experimental data with mathematical and computational modelling to provide evidence that extra centrioles in dendritic cells form over-active microtubule organizing centers, which cluster during dendritic cell-T cell interactions and, unlike in T cells, localize close to the cell center. Perturbing either centrosome integrity or centriole numbers and configuration in dendritic cells results in impaired T cell activation. Collectively, our results highlight a crucial role for centriole amplification and optimal centrosome positioning in antigen-presenting cells for controlling T cell responses.