IFNα8 drives STAT1-dependent HIV reactivation and persistence in memory CD4 T cells

Latent HIV persists in resting memory CD4 T cells and reignites infection when antiretroviral therapy is interrupted, making reservoir reversal and clearance central goals for HIV cure. We previously identified interferon alpha 8 (IFNα8) as a potent inducer of HIV reactivation in primary CD4 T cells, but the signalling mechanism remained undefined. Here, we mapped IFNα8-driven reactivation across IFN receptor-associated pathways using pharmacological inhibition, phosphoproteomics, proteomics, flow cytometry and microscopy. Blocking JAK1, Tyk2 or STAT1 markedly reduced IFNα8-induced HIV reactivation, whereas inhibition of STAT3, STAT4, STAT5, STAT6, PI3K, mTOR or NF-κB did not. Phosphoproteomic profiling confirmed selective activation of JAK–STAT signalling, and microscopy revealed nuclear translocation of pSTAT1, pSTAT4 and pSTAT6 following IFNα8 stimulation, with STAT1 emerging as the dominant mediator of HIV reactivation. Proteomic analysis showed that IFNα8 induced a STAT1 centred interferon-stimulated gene network, enhanced viral RNA sensing and antiviral restriction, while downregulating host repressors of HIV transcription, including MyoD family inhibitor domain-containing protein (MDFIC) and zinc finger protein 324 (ZNF324). IFNα8 also induced the anti-apoptotic proteins CASP8 and FADD-like apoptosis regulator (, CFLAR) and Myeloid Cell Leukemia 1 (MCL1), suggesting that reactivated infected cells may resist HIV-induced cell death. These findings identify STAT1-dependent JAK–STAT signalling as the central pathway linking IFNα8 to HIV reactivation, while revealing a dual programme in which IFNα8 promotes viral transcription, limits HIV spread and supports infected-cell long term persistence. This highlights the need to pair latency reversal with effective immune-mediated clearance strategies.