Transforming growth factor-ß promotes the function of HIV-specific CXCR5+ CD8 T cells.

HIV replication can be inhibited by CXCR5+ CD8 T cells (follicular cytotoxic T cell [TFC]) which transfer into B-cell follicles where latent HIV infection persists. However, how cytokines affect TFC remain unclear. Understanding which cytokines show the ability to affect TFC could be a key strategy toward curing HIV. Similar mechanisms could be used for the growth and transfer of TFCs and follicular helper T (TFH) cells; as a result, we hypothesized that cytokines IL-6, IL-21, and transforming growth factor-ß (TGF-ß), which are necessary for the differentiation of TFH cells, could also dictate the development of TFCs. In this work, lymph node mononuclear cells and peripheral blood mononuclear cells from HIV-infected individuals were cocultured with IL-6, IL-21, and TGF-ß. We then carried out T-cell receptor (TCR) repertoire analysis to compare the differences between CXCR5- and CXCR5+ CD8 T cells. Our results showed that the percentage and function of TFC can be enhanced by stimulation with TGF-ß. Besides, TGF-ß stimulation enhanced the diversity of TCR and complementarity-determining region 3 sequences. HIV DNA showed a negative correlation with TFC. The use of TGF-ß to promote the expression of CXCR5+ CD8 T cells could become a new treatment approach for curing HIV.

Expression of CD39 Is Correlated With HIV DNA Levels in Naïve Tregs in Chronically Infected ART Naïve Patients.

Background: Treg cells represent important viral reservoirs during chronic HIV infection. CD39 is closely involved in Treg-mediated immunosuppressive effects. However, CD39 expression on nTregs and mTregs and a relationship with HIV DNA levels during HIV infection is still unclear. In this study, we analyzed the distribution of HIV DNA in Treg subsets and the association between HIV DNA and CD39 expression on Treg subsets. Methods: Sixty-two HIV-infected patients with different HIV stages and 14 uninfected individuals were enrolled. nTregs (CD4+CD25+CD127lowCD45RO-) and mTregs (CD4+CD25+CD127lowCD45RO+) were isolated by magnetic selection and flow cytometric sorting. HIV DNA was quantified by real-time polymerase chain reaction (PCR). CD39 expression on nTregs and mTregs was analyzed by flow cytometry. Results: Higher levels of HIV DNA were detected in mTregs than those in nTregs during chronic HIV infection. The frequency of CD39+ nTregs and HIV DNA levels in nTregs were increased in patients with advanced HIV infection. Furthermore, HIV DNA levels in nTregs correlated positively with CD39+ nTreg frequency. CD39+ nTreg frequency was also increased in immune non-responders. Conclusions: mTregs and nTregs are both important reservoirs of virus during chronic HIV infection and HIV DNA levels increase in nTregs in patients with advanced HIV infection. We observed increased frequency of CD39+ nTregs and HIV DNA levels in nTregs in patients with advanced HIV infection. HIV DNA levels in nTregs correlated positively with CD39+ nTreg frequency.

Dichotomous Roles of Programmed Cell Death 1 on HIV-Specific CXCR5+ and CXCR5- CD8+ T Cells during Chronic HIV Infection.

BACKGROUND: CXCR5+CD8+ T cells have been demonstrated to play an important role in the control of chronic viral replication; however, the relationship between CXCR5+CD8+ T cells, HIV disease progression, and programmed cell death 1 (PD-1) expression profile on CXCR5+CD8+ T cells during HIV infection remain poorly understood. METHODS: We enrolled a total of 101 HIV patients, including 62 typical progressors, 26 complete responders (CRs), and 13 immune non-responders (INRs). Flow cytometric analysis, immunohistochemical staining, and relative function (i.e., cytokine secretion and PD-1 blockade) assays were performed to analyze the properties of CXCR5+CD8+ T cells. RESULTS: HIV-specific CXCR5+CD8+ T cells in the peripheral blood and distribution of CXCR5+CD8+ T cells in the lymph node (LN) were negatively correlated with disease progression during chronic HIV infection. PD-1 was highly expressed on CXCR5+CD8+ T cells and positively associated with peripheral CD4+ T cell counts. Functionally, IFN-γ and TNF-α production of CXCR5+CD8+ T cells were reduced by PD-1 pathway blockade, but the production of IFN-γ and TNF-α from CXCR5-CD8+ T cells increased in response to TCR stimulation. Interestingly, PD-1 expression was constantly retained on CXCR5+CD8+ T cells while significantly decreased on CXCR5-CD8+ T cells after successful antiretroviral treatment in chronic HIV-infected patients. CONCLUSION: PD-1+CXCR5+CD8+ T cells are functional cytotoxic T cells during chronic HIV infection. PD-1+CXCR5+CD8+ T cells may represent a novel therapeutic strategy for the disease.

An efficient PEGylated liposomal nanocarrier containing cell-penetrating peptide and pH-sensitive hydrazone bond for enhancing tumor-targeted drug delivery.

Cell-penetrating peptides (CPPs) as small molecular transporters with abilities of cell penetrating, internalization, and endosomal escape have potential prospect in drug delivery systems. However, a bottleneck hampering their application is the poor specificity for cells. By utilizing the function of hydration shell of polyethylene glycol (PEG) and acid sensitivity of hydrazone bond, we constructed a kind of CPP-modified pH-sensitive PEGylated liposomes (CPPL) to improve the selectivity of these peptides for tumor targeting. In CPPL, CPP was directly attached to liposome surfaces via coupling with stearate (STR) to avoid the hindrance of PEG as a linker on the penetrating efficiency of CPP. A PEG derivative by conjugating PEG with STR via acid-degradable hydrazone bond (PEG2000-Hz-STR, PHS) was synthesized. High-performance liquid chromatography and flow cytometry demonstrated that PHS was stable at normal neutral conditions and PEG could be completely cleaved from liposome surface to expose CPP under acidic environments in tumor. An optimal CPP density on liposomes was screened to guaranty a maximum targeting efficiency on tumor cells as well as not being captured by normal cells that consequently lead to a long circulation in blood. In vitro and in vivo studies indicated, in 4 mol% CPP of lipid modified system, that CPP exerted higher efficiency on internalizing the liposomes into targeted subcellular compartments while remaining inactive and free from opsonins at a maximum extent in systemic circulation. The 4% CPPL as a drug delivery system will have great potential in the clinical application of anticancer drugs in future.