Showing papers by "Fu-Sheng Wang published in 2009"

The decrease of regulatory T cells correlates with excessive activation and apoptosis of CD8+ T cells in HIV‐1‐infected typical progressors, but not in long‐term non‐progressors

Abstract: Persistent HIV infection results in a decrease in absolute counts of CD4(+) CD25(+) regulatory T cells (Treg). To investigate the role of decreased Treg counts in the regulation of excessive activation and apoptosis of CD8(+) T cells in human immunodeficiency virus (HIV)-1 infection, we characterized Treg in 83 HIV-1-infected individuals, including 19 long-term non-progressors (LTNPs) and 51 typical progressors (TPs) who were treatment-naive, and 13 AIDS patients on highly active antiretroviral therapy (HAART), of whom nine were complete responders (CRs) and the remaining four were non-responders (NRs) to the treatment. TPs but not LTNPs had a significant decrease in absolute counts of circulating Treg, which was inversely correlated with the activation and apoptosis of CD8(+) T cells. Efficient HAART was found to increase Treg counts in CR patients and temper the excessive activation and apoptosis of CD8(+) T cells. Moreover, isolated Treg significantly inhibited the spontaneous and anti-CD3-induced apoptosis of CD8(+) T cells in a dose-dependent manner in vitro. Thus, our findings indicate that the decrease in Treg closely correlates with the increase in apoptotic CD8(+) T cells and disease progression in chronic HIV-1 infection, and that Treg may play a key role in maintaining the balance between the amount and quality of CD8(+) T cells in HIV-1 infection. Manipulation of Treg function may be a promising strategy for immune therapy of this disease.

Treg suppress CTL responses upon immunization with HSP gp96.

Abstract: HSP gp96-based vaccines have been trialled in rodent models and, more recently, in humans. Better understanding of gp96's immunomodulatory role will help with the design of more effective strategies for treatment of cancer and infectious diseases. In this study, we monitored the activities of T cells and activation of Treg in BABL/c mice after immunization using different doses of gp96 as adjuvant. We found that co-injection of gp96 simultaneously stimulated both CTL and Treg activity. Activation of CTL at low dose was far more pronounced than Treg activation. Treg population and suppression increased with gp96 dose, eventually abrogating the T-cell response induced by immunization. Low-dose cyclophosphamide treatment could restore the T-cell responses lost after high-dose gp96 adjuvant injection by suppression of Treg activation. We further examined the effect of different doses of gp96 or N355 peptide administration on tumor rejection. Our results provide new insights into the mechanisms of gp96-mediated balance between regulatory and responder T cells, which may facilitate future development of an effective gp96-based therapeutic vaccine.

Progressive CD127 down-regulation correlates with increased apoptosis of CD8 T cells during chronic HIV-1 infection

Abstract: Chronic HIV-1 infection can induce a significant decrease in CD127 expression on CD8 T cells, but the underlying mechanisms and immunological consequences are unclear. In this study, we investigated CD127 expression on CD8 T cells from a total of 51 HIV-1-infected subjects and 16 healthy individuals and analyzed the association between CD127 expression and CD8 T-cell apoptosis in these HIV-1-infected subjects. We found that CD127 expression on total CD8 T cells was significantly down-regulated, which was correlated with the increased CD8 T-cell apoptosis and disease progression of chronic HIV-1 infection. The in vitro addition of IL-7 efficiently rescued the spontaneous apoptosis of CD8 T cells from HIV-1-infected individuals. IL-7 stimulation also transiently down-regulated CD127 expression, whereas some of the CD127(-) CD8 T cells regained CD127 expression soon after IL-7 was retracted from the incubation medium. Thus, IL-7 stimulation reduced apoptosis of both CD127(+) and CD127(-)CD8 T cells to some degree. These data indicate that CD127 loss might impair IL-7 signaling and increase CD8 T-cell apoptosis during HIV-1 infection. This study, therefore, will extend the notion that IL-7 could be a good candidate for immunotherapy in HIV-1-infected patients.

Viral suppression correlates with dendritic cell restoration in chronic hepatitis B patients with autologous cytokine-induced killer cell transfusion.

Abstract: Background: Myeloid and plasmacytoid dendritic cells (mDCs, pDCs) are functionally impaired in patients with chronic hepatitis B (CHB). Adoptive immunotherapy can suppress hepatitis B virus (HBV) replication in CHB patients, but whether it can restore the functionality of mDCs and pDCs remains unknown. Methods: Autologous cytokine-induced killer (CIK) cells obtained from 14 CHB patients were transfused back to patients, case by case, to observe the effect of CIK-cell treatment on the frequency and functionality of mDCs and pDCs in CHB patients during a 24-week follow-up investigation. Results: Seven virological responders exhibited a sustained decrease in HBV load after CIK-cell transfusion; another seven non-virological responders showed only sustained high levels of HBV load during the 24-week period following CIK-cell transfusion. The rate of hepatitis B e antigen loss or seroconversion was also higher in virological responders than in non-virological responders. Importantly, we found that the frequency and cytokine-producing capacity of mDCs and pDCs increased significantly in virological responders, but not in non-virological responders. In addition, these patients exhibited a close correlation between restoration DC subsets and a decrease in HBV DNA load, rather than a change in the alanine aminotransferase level. Conclusion: Cytokine-induced killer-cell treatment reduced HBV DNA load in some CHB patients; the efficiency at least partially correlates with the restoration of frequency and functionality of mDCs and pDCs.