Abstract

Patients with HIV routinely use medicinal cannabinoids to treat neuropathic pain, anxiety, and human immunodeficiency virus (HIV)–associated wasting. However, Δ⁹-tetrahydrocannabinol (THC), the primary psychoactive cannabinoid in cannabis, suppresses T-cell function and secretion of interferons, both critically important in the antiviral immune response. Interferon-α (IFNα), a key cytokine in T-cell activation and peripheral control of HIV infection, can potentiate responsiveness to interleukin-7 (IL-7), a crucial homeostatic cytokine for peripheral T-cell maintenance. The objective of this investigation was to compare the response of T cells to stimulation by IFNα and IL-7 in T cells from healthy and HIV⁺ donors in the absence and presence of THC. To compare T-cell responses between healthy and HIV⁺ donors signaling through IFNα receptor, IFNα-induced expression of IL-7α receptor (IL-7Rα), cognate signaling through IL-7R, and on IL-7–mediated T-cell proliferation were measured by flow cytometry and real-time quantitative polymerase chain reaction. CD8⁺ T cells from HIV⁺ donors showed a diminished response to IFNα-induced phosphorylated signal transducer and activator of transcription-1 activation compared with CD8⁺ T cells from healthy donors, whereas CD4⁺ T cells from HIV⁺ donors and healthy donors were comparable. Treatment with IFNα promoted IL-7R expression and potentiated IL-7–induced STAT5 phosphorylation to augment IL-7–mediated proliferation by T cells from healthy and HIV⁺ donors. Finally, HIV⁺ donors exhibited reduced sensitivity to THC-mediated suppression by IFNα- and IL-7–mediated stimulation compared with healthy donors. These results further support THC as being immune suppressive while identifying putatively beneficial aspects of cannabinoid-based therapies in HIV⁺ patients.