In Vivo T Cell-Targeting Nanoparticle Drug Delivery Systems: Considerations for Rational Design.

T cells play an important role in immunity and repair and are implicated in diseases, including blood cancers, viral infections, and inflammation, making them attractive targets for the treatment and prevention of diseases. Over recent years, the advent of nanomedicine has shown an increase in studies that use nanoparticles as carriers to deliver therapeutic cargo to T cells for ex vivo and in vivo applications. Nanoparticle-based delivery has several advantages, including the ability to load and protect a variety of drugs, control drug release, improve drug pharmacokinetics and biodistribution, and site- or cell-specific targeting. However, the delivery of nanoparticles to T cells remains a major technological challenge, which is primarily due to the nonphagocytic nature of T cells. In this review, we discuss the physiological barriers to effective T cell targeting and describe the different approaches used to deliver cargo-loaded nanoparticles to T cells for the treatment of disease such as T cell lymphoma and human immunodeficiency virus (HIV). In particular, engineering strategies that aim to improve nanoparticle internalization by T cells, including ligand-based targeting, will be highlighted. These nanoparticle engineering approaches are expected to inspire the development of effective nanomaterials that can target or manipulate the function of T cells for the treatment of T cell-related diseases.

Impact of alemtuzumab on HIV persistence in an HIV-infected individual on antiretroviral therapy with Sezary syndrome.

OBJECTIVE: To study the effects of alemtuzumab on HIV persistence in an HIV-infected individual on antiretroviral therapy (ART) with Sezary syndrome, a rare malignancy of CD4 T cells. DESIGN: Case report. METHODS: Blood was collected 30 and 18 months prior to presentation with Sezary syndrome, at the time of presentation and during alemtuzumab. T-cell subsets in malignant (CD7-CD26-TCR-VBeta2+) and nonmalignant cells were quantified by flow cytometry. HIV-DNA in total CD4 T cells, in sorted malignant and nonmalignant CD4 T cells, was quantified by PCR and clonal expansion of HIV-DNA assessed by full-length next-generation sequencing. RESULTS: HIV-hepatitis B virus coinfection was diagnosed and antiretroviral therapy initiated 4 years prior to presentation with Sezary syndrome and primary cutaneous anaplastic large cell lymphoma. The patient received alemtuzumab 10 mg three times per week for 4 weeks but died 6 weeks post alemtuzumab. HIV-DNA was detected in nonmalignant but not in malignant CD4 T cells, consistent with expansion of a noninfected CD4 T-cell clone. Full-length HIV-DNA sequencing demonstrated multiple defective viruses but no identical or expanded sequences. Alemtuzumab extensively depleted T cells, including more than 1 log reduction in total T cells and more than 3 log reduction in CD4 T cells. Finally, alemtuzumab decreased HIV-DNA in CD4 T cells by 57% but HIV-DNA remained detectable at low levels even after depletion of nearly all CD4 T cells. CONCLUSION: Alemtuzumab extensively depleted multiple T-cell subsets and decreased the frequency of but did not eliminate HIV-infected CD4 T cells. Studying the effects on HIV persistence following immune recovery in HIV-infected individuals who require alemtuzumab for malignancy or in animal studies may provide further insights into novel cure strategies.

HIV integration sites in latently infected cell lines: evidence of ongoing replication.

BACKGROUND: Assessing the location and frequency of HIV integration sites in latently infected cells can potentially inform our understanding of how HIV persists during combination antiretroviral therapy. We developed a novel high throughput sequencing method to evaluate HIV integration sites in latently infected cell lines to determine whether there was virus replication or clonal expansion in these cell lines observed as multiple integration events at the same position. RESULTS: We modified a previously reported method using random DNA shearing and PCR to allow for high throughput robotic processing to identify the site and frequency of HIV integration in latently infected cell lines. Latently infected cell lines infected with intact virus demonstrated multiple distinct HIV integration sites (28 different sites in U1, 110 in ACH-2 and 117 in J1.1 per 150,000 cells). In contrast, cell lines infected with replication-incompetent viruses (J-Lat cells) demonstrated single integration sites. Following in vitro passaging of the ACH-2 cell line, we observed a significant increase in the frequency of unique HIV integration sites and there were multiple mutations and large deletions in the proviral DNA. When the ACH-2 cell line was cultured with the integrase inhibitor raltegravir, there was a significant decrease in the number of unique HIV integration sites and a transient increase in the frequency of 2-LTR circles consistent with virus replication in these cells. CONCLUSION: Cell lines latently infected with intact HIV demonstrated multiple unique HIV integration sites indicating that these cell lines are not clonal and in the ACH-2 cell line there was evidence of low level virus replication. These findings have implications for the use of latently infected cell lines as models of HIV latency and for the use of these cells as standards.

Dependence on the CCR5 coreceptor for viral replication explains the lack of rebound of CXCR4-predicted HIV variants in the Berlin patient.

The "Berlin patient" is the first patient cured of HIV-1 infection after allogeneic transplantation with nonfunctional CCR5 coreceptor stem cells. We demonstrate that CXCR4-predicted minority viruses present prior to transplantation were unable to rebound after transplantation due to their dependence on CCR5 for replication and high genetic barrier toward CXCR4 usage.

HIV population genotypic tropism testing and its clinical significance.

PURPOSE OF REVIEW: HIV co-receptor tropism testing is recommended before therapy when the C-C chemokine receptor type 5 antagonist maraviroc is initiated. This review addresses the use of population genotypic tropism testing in relation to clinical practice. RECENT FINDINGS: Genotypic tropism tests predict viral co-receptor tropism based on the sequence of the V3 loop of the viral envelope. HIV occurs in a swarm of variants in the patient's body, called quasispecies. As next-generation sequencing techniques are not generally accessible to date, triplicate testing is often performed to improve sensitivity of population-based approaches, but no prospective studies assessing the performance of single and triplicate procedures related to clinical outcome have been performed yet. For interpretation of the genotype several web-based algorithms have been developed. Varying the cut-off of the commonly used geno2pheno[co-receptor] algorithm changes the sensitivity and specificity of the tropism prediction. In retrospective analyses of clinical studies and cohorts genotypic population tropism testing demonstrated equal correlation with clinical outcome on maraviroc compared with phenotypic assays.In patients with suppressed viraemia, proviral DNA testing is a well tolerated alternative to HIV-RNA testing. SUMMARY: Population genotypic methods have greater accessibility, lower cost, and faster turnaround time than other methods. Despite limited sensitivity for minority variants HIV genotypic population tropism testing showed good correlation with clinical outcome.