Cellular pharmacology and potency of HIV-1 nucleoside analogs in primary human macrophages

Abstract

Understanding the cellular pharmacology of antiretroviral agents in macrophages and subsequent correlation with antiviral potency provides a sentinel foundation for definition of the dynamics between antiretroviral agents and viral reservoirs across multiple cell types, with the goal of eradication of HIV-1 from these cells. Various clinically relevant nucleoside antiviral agents, and the integrase inhibitor raltegravir, were selected for this study. The intracellular concentrations of the active metabolites of the nucleoside analogs were found to be 5- to 140-fold lower in macrophages than in lymphocytes, and their antiviral potency was significantly lower in macrophages constitutively activated with macrophage colony-stimulating factor (M-CSF) during acute infection than in resting macrophages (EC(50), 0.4 to 9.42 μM versus 0.03 to 0.4 μM, respectively). Although tenofovir-treated cells displayed significantly lower intracellular drug levels than cells treated with its prodrug, tenofovir disoproxil fumarate, the levels of tenofovir-diphosphate for tenofovir-treated cells were similar in lymphocytes and macrophages. Raltegravir also displayed significantly lower intracellular concentrations in macrophages than in lymphocytes, independent of the activation state, but had similar potencies in resting and activated macrophages. These data underscore the importance of delivering adequate levels of drug to macrophages to reduce and eradicate HIV-1 infection.

Fig 1

Intracellular concentrations of ART drugs are significantly lower in Mϕ than in PBM cells independent of the activation state (A to D and F to I), with the exception of those of TFV, which were similar in both PBM cells and Mϕ. For all NRTIs tested, the EC₅₀ for chronically infected Mϕ was >50 μM (data not shown), and constitutive activation significantly diminished potency versus resting Mϕ (A to I). The potencies of raltegravir and atazanavir (data not shown) and of raltegravir (I) were similar for resting and activated Mϕ. The data represent means and standard deviations calculated from at least 5 independent experiments conducted with duplicates within each experiment. a, statistically significant difference relative to PBM cells (P < 0.01); b, significant difference relative to resting PBM cells (P < 0.05).