A Subset of Latency-Reversing Agents Expose HIV-Infected Resting CD4⁺ T-Cells to Recognition by Cytotoxic T-Lymphocytes

Resting CD4⁺ T-cells harboring inducible HIV proviruses are a critical reservoir in antiretroviral therapy (ART)-treated subjects. These cells express little to no viral protein, and thus neither die by viral cytopathic effects, nor are efficiently cleared by immune effectors. Elimination of this reservoir is theoretically possible by combining latency-reversing agents (LRAs) with immune effectors, such as CD8⁺ T-cells. However, the relative efficacy of different LRAs in sensitizing latently-infected cells for recognition by HIV-specific CD8⁺ T-cells has not been determined. To address this, we developed an assay that utilizes HIV-specific CD8⁺ T-cell clones as biosensors for HIV antigen expression. By testing multiple CD8⁺ T-cell clones against a primary cell model of HIV latency, we identified several single agents that primed latently-infected cells for CD8⁺ T-cell recognition, including IL-2, IL-15, two IL-15 superagonists (IL-15SA and ALT-803), prostratin, and the TLR-2 ligand Pam₃CSK₄. In contrast, we did not observe CD8⁺ T-cell recognition of target cells following treatment with histone deacetylase inhibitors or with hexamethylene bisacetamide (HMBA). In further experiments we demonstrate that a clinically achievable concentration of the IL-15 superagonist ‘ALT-803’, an agent presently in clinical trials for solid and hematological tumors, primes the natural ex vivo reservoir for CD8⁺ T-cell recognition. Thus, our results establish a novel experimental approach for comparative evaluation of LRAs, and highlight ALT-803 as an LRA with the potential to synergize with CD8⁺ T-cells in HIV eradication strategies.United States. National Institutes of Health (AI111860

Differential inhibitory effects of indomethacin, dexamethasone, and interferon-gamma (IFN-γ) on IL-11 production by rheumatoid synovial cells

IL-11, a member of the IL-6 type cytokines, has some biological activity related to the joint destruction in rheumatoid arthritis (RA), such as induction of osteoclast differentiation. However, its expression and regulation in rheumatoid inflamed joints has not been clarified. In the present study we examined the capacity of fresh rheumatoid synovial cells (fresh RSC) to produce IL-11, and the effect of indomethacin, dexamethasone and IFN-γ on IL-11 production. Fresh RSC obtained from eight patients with RA produced large amounts of IL-11, measured by ELISA, and showed strong expression of IL-11 mRNA, determined by Northern blotting. Indomethacin inhibited the production of IL-11 by about 55%. Prostaglandin E2 (PGE2) completely prevented the inhibition, suggesting that IL-11 production by fresh RSC was in part mediated by PGE2. Dexamethasone inhibited the production of IL-11 by more than 80%. Interestingly, the inhibition was not abolished by PGE2. IFN-γ inhibited the production of IL-11 from IL-1α-stimulated cultured rheumatoid synovial fibroblasts, although IFN-γ did not inhibit the production of IL-11 by fresh RSC. These results suggest that the production of IL-11 by rheumatoid synovia was differentially regulated by PGE2 and IFN-γ, and that treatment with indomethacin or dexamethasone decreased the level of IL-11 at inflammatory joints in patients with RA