HIV-1 Infection Results in Sphingosine-1-Phosphate Receptor 1 Dysregulation in the Human Thymus.

Regeneration of functional naïve T lymphocytes following the onset of human immunodeficiency virus (HIV) infection remains a crucial issue for people living with HIV (PLWH), even when adhering to antiretroviral therapy (ART). Thus far, reports on the impact of HIV-1 infection on the entry of thymic precursors and the egress of functional naïve T lymphocytes to and from the thymus are limited. We examined the impact of HIV-1 on Sphingosine-1-phosphate (S1P) signaling, which governs the egress of functional naïve thymocytes from the thymus to the periphery.

No reliable gene expression biomarkers of current or impending neurocognitive impairment in peripheral blood monocytes of persons living with HIV.

Events leading to and propagating neurocognitive impairment (NCI) in HIV-1-infected (HIV+) persons are largely mediated by peripheral blood monocytes. We previously identified expression levels of individual genes and gene networks in peripheral blood monocytes that correlated with neurocognitive functioning in HIV+ adults. Here, we expand upon those findings by examining if gene expression data at baseline is predictive of change in neurocognitive functioning 2 years later.

HIV integration and the establishment of latency in CCL19-treated resting CD4(+) T cells require activation of NF-κB.

Background: Eradication of HIV cannot be achieved with combination antiretroviral therapy (cART) because of the persistence of long-lived latently infected resting memory CD4(+) T cells. We previously reported that HIV latency could be established in resting CD4(+) T cells in the presence of the chemokine CCL19. To define how CCL19 facilitated the establishment of latent HIV infection, the role of chemokine receptor signalling was explored.

Cocaine-mediated impact on HIV infection in humanized BLT mice.

Cocaine abuse has been shown to have broad-ranging effects on human immunity. With regards to HIV infection, in vitro studies have shown that cocaine enhances infection of stimulated lymphocytes. Moreover, cohort studies in the pre- and post-HAART era have linked stimulant abuse with increased HIV pathogenesis.

Engineering Cellular Resistance to HIV-1 Infection In Vivo Using a Dual Therapeutic Lentiviral Vector.

We described earlier a dual-combination anti-HIV type 1 (HIV-1) lentiviral vector (LVsh5/C46) that downregulates CCR5 expression of transduced cells via RNAi and inhibits HIV-1 fusion via cell surface expression of cell membrane-anchored C46 antiviral peptide. This combinatorial approach has two points of inhibition for R5-tropic HIV-1 and is also active against X4-tropic HIV-1. Here, we utilize the humanized bone marrow, liver, thymus (BLT) mouse model to characterize the in vivo efficacy of LVsh5/C46 (Cal-1) vector to engineer cellular resistance to HIV-1 pathogenesis.

Noninvasive detection of tumor-infiltrating T cells by PET reporter imaging.

Adoptive transfer of tumor-reactive T cells can successfully reduce tumor burden; however, in rare cases, lethal on-target/off-tumor effects have been reported. A noninvasive method to track engineered cells with high sensitivity and resolution would allow observation of correct cell homing and/or identification of dangerous off-target locations in preclinical and clinical applications. Human deoxycytidine kinase triple mutant (hdCK3mut) is a nonimmunogenic PET reporter that was previously shown to be an effective tool to monitor whole-body hematopoiesis.

Cocaine exposure impairs multilineage hematopoiesis of human hematopoietic progenitor cells mediated by the sigma-1 receptor [corrected].

Prenatal exposure to cocaine is a significant source of fetal and neonatal developmental defects. While cocaine associated neurological and cardiac pathologies are well-documented, it is apparent that cocaine use has far more diverse physiological effects. It is known that in some cell types, the sigma-1 receptor mediates many of cocaine's cellular effects.

HIV-1 infection of hematopoietic progenitor cells in vivo in humanized mice.

HIV infection has been associated with defective hematopoiesis since the earliest days of the HIV/AIDS epidemic. Generation of all hematopoietic lineages suffers in the face of infection. The mechanisms by which HIV impairs normal blood cell development remain unclear, and direct infection of intermediate hematopoietic progenitors has not been established as a source of HIV-associated hematopoietic pathology.

Cocaine exposure enhances permissiveness of quiescent T cells to HIV infection.

In vivo and in vitro exposure to stimulants has been associated with increased levels of HIV infection in PBMCs. Among these lymphocyte subsets, quiescent CD4(+) T cells make up the majority of circulating T cells in the blood. Others and we have demonstrated that HIV infects this population of cells inefficiently.

HIV restriction in quiescent CD4⁺ T cells.

The restriction of the Human Immunodeficiency Virus (HIV) infection in quiescent CD4⁺ T cells has been an area of active investigation. Early studies have suggested that this T cell subset is refractory to infection by the virus. Subsequently it was demonstrated that quiescent cells could be infected at low levels; nevertheless these observations supported the earlier assertions of debilitating defects in the viral life cycle.

Introduction of exogenous T-cell receptors into human hematopoietic progenitors results in exclusion of endogenous T-cell receptor expression.

Current tumor immunotherapy approaches include the genetic modification of peripheral T cells to express tumor antigen-specific T-cell receptors (TCRs). The approach, tested in melanoma, has led to some limited success of tumor regression in patients. Yet, the introduction of exogenous TCRs into mature T cells entails an underlying risk; the generation of autoreactive clones due to potential TCR mispairing, and the lack of effective negative selection, as these peripheral cells do not undergo thymic selection following introduction of the exogenous TCR.

Using the BLT humanized mouse as a stem cell based gene therapy tumor model.

Small animal models such as mice have been extensively used to study human disease and to develop new therapeutic interventions. Despite the wealth of information gained from these studies, the unique characteristics of mouse immunity as well as the species specificity of viral diseases such as human immunodeficiency virus (HIV) infection led to the development of humanized mouse models. The earlier models involved the use of C.

Engineering hematopoietic stem cells to create melanoma specific CTL.

Using a humanized mouse model, we developed melanoma specific CD8 T cells from genetically modified human hematopoietic stem cells (hHSC). The transgenic T cells were functional both in vivo and ex vivo, effectively limiting and clearing tumor growth. Finally, the transduced hHSC stably populated the bone marrow.

Antitumor activity from antigen-specific CD8 T cells generated in vivo from genetically engineered human hematopoietic stem cells.

The goal of cancer immunotherapy is the generation of an effective, stable, and self-renewing antitumor T-cell population. One such approach involves the use of high-affinity cancer-specific T-cell receptors in gene-therapy protocols. Here, we present the generation of functional tumor-specific human T cells in vivo from genetically modified human hematopoietic stem cells (hHSC) using a human/mouse chimera model.

Genome-wide binding map of the HIV-1 Tat protein to the human genome.

The HIV-1 Trans-Activator of Transcription (Tat) protein binds to multiple host cellular factors and greatly enhances the level of transcription of the HIV genome. While Tat's control of viral transcription is well-studied, much less is known about the interaction of Tat with the human genome. Here, we report the genome-wide binding map of Tat to the human genome in Jurkat T cells using chromatin immunoprecipitation combined with next-generation sequencing.

The signal peptide sequence impacts the immune response elicited by a DNA epitope vaccine.

We examined the effect of two leader sequences, one from a transmembrane molecule (H2-L(d)) and another from a secreted molecule (rat KC chemokine), on the immunogenicity of DNA epitope vaccines. The chemokine leader enhanced vaccine immunogenicity, thus underscoring the importance of the leader sequence in DNA epitope vaccine design.

Quiescent T cells and HIV: an unresolved relationship.

The ability of HIV to infect quiescent CD4+ T cells has been a topic of intense debate. While early studies suggested that the virus could not infect this particular T cell subset, subsequent studies using more sensitive protocols demonstrated that these cells could inefficiently support HIV infection. Additional studies showed that the kinetics of infection in quiescent cells was delayed and multiple stages of the viral life cycle were marred by inefficiencies.

Human immunodeficiency virus integration efficiency and site selection in quiescent CD4+ T cells.

Until very recently, quiescent CD4(+) T cells were thought to be resistant to human immunodeficiency virus (HIV) infection. Subsequent studies, attempting to fully elucidate the mechanisms of resistance, showed that quiescent cells could become infected by HIV at low efficiency and form a latently infected population. In this study, we set out to identify the sites of viral integration and to assess the efficiency of the overall integration process in quiescent cells.

Differentially stimulated CD4+ T cells display altered human immunodeficiency virus infection kinetics: implications for the efficacy of antiviral agents.

The activation state of CD4(+) T cells plays a crucial role in the establishment of a productive human immunodeficiency virus infection. Here, we show that T cells stimulated for 1 day demonstrated delayed kinetics of viral reverse transcription and integration compared to cells stimulated for 2 days prior to infection. As a result, the efficiency of reverse transcription and integration inhibitors differs in these differentially stimulated cells.

Viral complementation allows HIV-1 replication without integration.

Background: The integration of HIV-1 DNA into cellular chromatin is required for high levels of viral gene expression and for the production of new virions. However, the majority of HIV-1 DNA remains unintegrated and is generally considered a replicative dead-end. A limited amount of early gene expression from unintegrated DNA has been reported, but viral replication does not proceed further in cells which contain only unintegrated DNA.

Primary cell model for activation-inducible human immunodeficiency virus.

Quiescent T lymphocytes containing latent human immunodeficiency virus (HIV) provide a long-lived viral reservoir. This reservoir may be the source of active infection that is reinitiated following the cessation of antiretroviral therapy. Therefore, it is important to understand the mechanisms involved in latent infection to develop new strategies to eliminate the latent HIV reservoir.

Immediate activation fails to rescue efficient human immunodeficiency virus replication in quiescent CD4+ T cells.

Unlike activated T cells, quiescent CD4+ T cells have shown resistance to human immunodeficiency virus (HIV) infection due to a block in the early events of the viral life cycle. To further investigate the nature of this block, we infected quiescent CD4+ T cells with HIV-1(NL4-3) and immediately stimulated them. Compared to activated (prestimulated) cells, these poststimulated cells showed slightly decreased viral entry and delays in the completion of reverse transcription.

Rapid expression of human immunodeficiency virus following activation of latently infected cells.

The host cell activation state impacts the nature of human immunodeficiency virus infection. Activated cells facilitate productive infections; quiescent cells enable the virus to enter a latent state, the major obstacle to viral clearance. We wanted to understand how these differences affected viral gene expression.

CD4+ T cell epitope affinity to MHC II influences the magnitude of CTL responses elicited by DNA epitope vaccines.

Immunization with naked plasmid DNA elicits strong cell-mediated immune responses. In the present study, we examine strategies to enhance epitope-specific cytotoxic T lymphocyte (CTL) responses using DNA constructs, expressing a minimal class I epitope of the gp120 of HIV-IIIB. Here, we evaluate the effect of CD4+ T cell (T(H)) epitope affinity for the MHC II molecule on the immunogenicity of our DNA vaccines.