Maraviroc intensification in patients with suppressed HIV viremia has limited effects on CD4+ T cell recovery and gene expression.

Addition of the CCR5 inhibitor Maraviroc (MVC) to ongoing antiretroviral therapy increases CD4+ T cell counts in some virologically suppressed patients with suboptimal CD4+ T cell recovery. To understand the mechanisms by which MVC elicits increases in CD4+ T cell counts, the present study was undertaken to identify host factors (i.e. genes) that are modulated and are correlated with CD4+ T cell recovery during the 24weeks of MVC intensification in 32 subjects. Median changes of CD4+ T cell counts over 24weeks of MVC compared to baseline were 38cells/mm(3) (p<0.001). The median slope of CD4+ T cell recovery was 39cells/mm(3) per year before initiation of MVC and 76cells/mm(3) per year during MVC intensification, however, this increase was not statistically significant (p=0.33). Microarray analysis (N=31,426 genes) identified a single differentially expressed gene, tumor necrosis factor alpha (TNF), which was modestly (1.44-fold, p<0.001) downregulated by MVC at week 24 compared to baseline. TNF differential expression was evaluated using an independent method of droplet digital PCR, but the difference was not significant (p=0.6). Changes in gene expression did not correlate with CD4+ T cell recovery or any changes in the CD4+ T cell maturation, proliferation and activation phenotypes. In summary, our data suggest that modest improvements of CD4+ T cell counts during MVC intensification cannot be explained by changes in gene expression elicited by MVC. However, the modest changes in T cell composition, including reduction of the percentages of Tregs, proliferating CD4+ T cells and senescent CD8+ T cells, suggest immunologically favorable effects of MVC.

HIV downregulates interferon-stimulated genes in primary macrophages.

HIV is able to outpace the innate immune response, including that mediated by interferon (IFN), to establish a productive infection. Primary macrophages, however, may be protected from HIV infection by treatment with type I IFN before virus exposure. The ability of HIV to modulate the type I IFN-mediated innate immune response when it encounters a cell that has already been exposed to IFN remains poorly defined. The optimal pretreatment time (12 h) and the most potent HIV-inhibitors (e.g., IFN-α2 and -ω) were identified to investigate the ability of HIV to modulate an established type I IFN response. Gene expression at the level of the entire transcriptome was then compared between primary macrophages treated with type I IFNs, as opposed to treated with IFNs and then infected with HIV. Although HIV was not able to establish a robust infection, the virus was able to downregulate a number of IFN-stimulated genes (ISGs) with a fold change greater than 1.5 (i.e., AXL, IFI27, IFI44, IFI44L, ISG15, OAS1, OAS3, and XAF1). The downregulation of OAS1 by the presence of HIV was confirmed by real-time quantitative polymerase chain reaction. In conclusion, even though HIV replication is significantly inhibited by IFN pretreatment, the virus is able to downregulate the transcription of known antiviral ISGs (e.g., IFI44, ISG15, and OAS1).

Associations between virologic and immunologic dynamics in blood and in the male genital tract.

To determine the influence of asymptomatic genital viral infections on the cellular components of semen and blood, we evaluated the associations between the numbers and activation statuses of CD4+ and CD8+ T lymphocytes in both compartments and the seminal levels of cytomegalovirus (CMV), herpes simplex virus (HSV), and human immunodeficiency virus 1 (HIV). Paired blood and semen samples were collected from 36 HIV-infected antiretroviral-naïve individuals and from 40 HIV-uninfected participants. We performed multiparameter flow cytometry analysis (CD45, CD45RA, CD3, CD4, CD8, and CD38) of seminal and blood cellular components and measured HIV RNA and CMV and HSV DNA levels in seminal and blood plasma by real-time PCR. Compared to HIV-uninfected participants, in the seminal compartment HIV-infected participants had higher levels of CMV (P < 0.05), higher numbers of total CD3+ (P < 0.01) and CD8+ subset (P < 0.01) T lymphocytes, and higher CD4+ and CD8+ T lymphocyte activation (RA-CD38+) (P < 0.01). Seminal CMV levels positively correlated with absolute numbers of CD4+ and CD8+ T cells in semen (P < 0.05) and with the activation status of CD4+ T cells in semen and in blood (P < 0.01). HIV levels in semen (P < 0.05) and blood (P < 0.01) were positively associated with T-cell activation in blood. Activation of CD8+ T cells in blood remained an independent predictor of HIV levels in semen in multivariate analysis. The virologic milieu in the male genital tract strongly influences the recruitment and activation of immune cells in semen and may also modulate T-cell immune activation in blood. These factors likely influence replication dynamics, sexual transmission risk, and disease outcomes for all three viruses.

Interferon gene expression following HIV type 1 infection of monocyte-derived macrophages.

Macrophages represent one of the primary targets of HIV-1 infection. Changes in gene expression in primary human monocyte-derived macrophages following virus exposure were assessed using oligonucleotide arrays. Over a third of the 100 most modulated genes belonged to the interferon system. Upregulated interferon-stimulated genes included those essential for the innate immune response and also those involved in interferon and virus signal transduction from the cell surface. The promoter regions of a cluster of highly upregulated interferon-stimulated genes were analyzed for common regulatory elements. The nuclear factor in activated T cells (NFAT) and members of the interferon family of transcription factors appeared to be responsible for the upregulation of this set of interferon-stimulated genes following HIV-1 exposure.

Gene expression profiling detects patterns of human macrophage responses following Mycobacterium tuberculosis infection.

High-density oligonucleotide microarrays allow simultaneous monitoring of the expression of a large number of cellular genes. Microarrays were used to screen the global human monocyte-derived macrophage transcriptional response to infection with the intracellular pathogen Mycobacterium tuberculosis. The microarray detected reproducible patterns of regulated gene expression. Analysis of the expression data showed induction of cytokines and chemokines, ribosomal proteins, and the interferon-response gene Stat1. Several changes were validated by quantitative reverse transcription polymerase chain reaction and immunoblot assays. Augmentation of the respiratory burst and preservation of the response to interferon-gamma were also demonstrated. These data supplement existing knowledge on macrophage responses to tuberculosis infection.