Long‐term survival and virus production in human primary macrophages infected by human immunodeficiency virus

Abstract

The role of macrophages in the pathogenesis and progression of human immunodeficiency virus (HIV)-related infection is substantiated by in vitro and in vivo evidence. The unique ability to survive HIV infection and produce viral particles for long periods is postulated. Detailed studies of this phenomenon are lacking. The dynamics of HIV-1 replication and cumulative virus production was studied in long-term cultures of macrophages in the presence or in the absence of antiviral drugs. Multiply spliced and unspliced HIV-RNA production was assessed by quantitative PCR, and the number of infected cells was monitored by FACS analysis. Cumulative HIV-1 production was determined by a trapezoidal equation, including such parameters as times of collection and experimental values of genomic-RNA and p24 gag antigen. Unspliced and multiply spliced HIV-RNA increased linearly after macrophage infection; reached levels of 1.5 x 10(8) and 2.8 x 10(5) copies/10(5) cells, respectively, at day 10; and then remained stable throughout the course of the experiment. Cumulative production of genomic-RNA and p24 gag antigen was 10(10) copies/10(6) cells and 10(7) pg/10(6) cells, respectively, with an average of >200 virus particles produced daily by each macrophage. AZT decreased the cumulative production of both genomic-RNA and p24 gag antigen down to 2.5 x 10(9) copies and 1.1 x 10(6) pg/10(6) cells (73.8% and 88.9% inhibition, respectively) up to day 50 without virus breakthrough. Ritonavir had a limited, but consistent, efficacy on the release of mature virus proteins (about 40% inhibition), but not on HIV-RNA production. In conclusion, the long-term dynamics and the high cumulative virus production that characterize HIV-1 infection of macrophages underscore the peculiar role of these cells as a persistently infected reservoir of HIV.

Cellular Pharmacology and Potency of HIV-1 Nucleoside Analogs in Primary Human Macrophages

“…We further demonstrate that, compared to macrophages maintained in the absence of M-CSF, acutely infected cells that are constitutively maintained in the presence of M-CSF displayed significantly diminished antiviral potency (EC 50 , 0.03 to 0.40 M versus 0.4 to 9.42 M, respectively). These data are confirmed by previous studies (2,8,10) on the antiviral potencies of NRTIs in chronically infected macrophages and are also in agreement with reports demonstrating the potencies of protease inhibitors against chronically and acutely infected lymphocytes and macrophages (10). The cellular-pharmacology studies also demonstrated for the first time that the intracellular concentration of RAL was significantly lower in macrophages than in lymphocytes, independent of the activation state.…”

“…These factors create many distinct and often concomitant microenvironments with heterogeneous exposures to extracellular drug concentrations relative to systemic CD4 ϩ T lymphocytes. Macrophages are a target for early infection (1,3,8) and are present in multiple sites of primary transmission, including the gut and genital tract (1,2,4). Infection in macrophages often results in subpopulations of latent infection, which can occur across any tissue or organ containing these cells, such as the brain or lymphoid tissues, rendering them a ubiquitous source for reactivation of virus later in disease progression.…”

“…Although the antiviral profile of antiretroviral therapy (ART) is partially defined in macrophages (2,(9)(10)(11), a direct link between potency and cellular pharmacology had not been reported. The relationship between the cellular pharmacology of ART and macrophages can impact viral loads, emergence of resistant HIV-1, and the long-term survival of infected individuals (8,12). For these reasons, understanding the dynamics of ART pharmacology in macrophages and subsequent targeted elimination of both the cells and the virus that they harbor are critical to eliminating HIV-1 infection.…”

LEAPT: Lectin-directed enzyme-activated prodrug therapy

“…The applicability of such an approach will depend on the identification of suitable receptors of potential medical relevance, e.g., the use of macrophage-associated carbohydrate receptors (14,39) to treat macrophage-associated diseases such as lysosomal storage disease (40) or viral infections (41). Moreover, the additional benefit of rhamnose targeting (and hence double targeting) in the current liver LEAPT system might be lost in other tissue͞cell systems, necessitating a reliance on passive small-molecule mechanisms such as pinocytosis.…”

p21-mediated RNR2 repression restricts HIV-1 replication in macrophages by inhibiting dNTP biosynthesis pathway

“…Because of their longevity and relative resistance to the cytopathogenic effect of HIV-1, macrophages contribute to the establishment of viral reservoirs and are able to transmit the virus to other target cells (2)(3)(4). HIV-1 infection of macrophages also affects their functions in innate and adaptive responses to pathogens (5).…”