Lymphoid tissue chemokines limit priming duration to preserve CD8⁺ T cell functionality.

Abstract

The generation of effector CD8⁺ T cells (T_EFF) requires activation of naïve CCR7⁺ T cells (T_N) by dendritic cells (DCs) in lymphoid tissue. How T_N-DC interaction duration and signal integration are controlled remains unclear. In this study, we show that lymphoid stroma-secreted CCR7 ligands limit interaction duration by progressively inducing CD8⁺ T cell release from DCs. At late interaction stages, CCR7 ligands relocalize the F-actin regulator DOCK2 away from the DC interface, permitting T cell detachment, proliferation onset, and acquisition of cytotoxicity. Disruption of CCR7 signaling causes prolonged T cell-DC contacts and produces dysfunctional T_EFF with elevated inhibitory receptors, reduced antimicrobial activity, and impaired recall responses. Stromal chemokines therefore act as critical regulators of T cell priming by DCs, preserving CD8⁺ effector function during acute and memory phases.