Summary: Background: Harnessing CD8+ T cell responses is being explored to achieve HIV remission. Although HIV-specific CD8+ T cells become dysfunctional without treatment, antiretroviral therapy (ART) partially restores their function. However, the extent of this recovery under long-term ART is less understood. Methods: We analyzed the differentiation status and function of HIV-specific CD8+ T cells after long-term ART initiated in acute or chronic HIV infection ex vivo and upon in vitro recall. Findings: ART initiation in any stage of acute HIV infection promoted the persistence of long-lived HIV-specific CD8+ T cells with high expansion (P