Application of recipient-derived dendritic cells to induce donor-specific T-cell hyporesponsiveness

Dendritic cell sphingosine 1-phosphate receptor-3 regulates Th1-Th2 polarity in kidney ischemia-reperfusion injury

Dendritic cells (DCs) are central to innate and adaptive immunity of early kidney ischemia-reperfusion injury (IRI), and strategies to alter DC function may provide new therapeutic opportunities. Sphingosine 1-phosphate (S1P) modulates immunity through binding to its receptors (S1P1-5), and protection from kidney IRI occurs in S1P3-deficient mice. Through a series of experiments we determined that this protective effect was owing in part to differences between S1P3-sufficient and -deficient DCs. Mice lacking S1P3 on bone marrow cells were protected from IRI, and S1P3-deficient DCs displayed an immature phenotype. Wild-type (WT) but not S1P3-deficient DCs injected into mice depleted of DCs prior to kidney IR reconstituted injury. Adoptive transfer (i.e., i.v. injection) of glycolipid (Ag)-loaded WT but not S1P3-deficient DCs into WT mice exacerbated IRI, suggesting that WT but not S1P3-deficient DCs activated NKT cells. Whereas WT DC transfers activated the Th1/IFN-γ pathway, S1P3-deficient DCs activated the Th2/IL-4 pathway, and an IL-4-blocking Ab reversed protection from IRI, supporting the concept that IL-4 mediates the protective effect of S1P3-deficient DCs. Administration of S1P3-deficient DCs 7 d prior to or 3 h after IRI protected mice from IRI and suggests their potential use in cell-based therapy. We conclude that absence of DC S1P3 prevents DC maturation and promotes a Th2/IL-4 response. These findings highlight the importance of DC S1P3 in modulating NKT cell function and IRI and support development of selective S1P3 antagonists for tolerizing DCs for cell-based therapy or for systemic administration for the prevention and treatment of IRI and autoimmune diseases.

Adoptive transfusion of tolerance dendritic cells prolongs the survival of cardiac allograft: a systematic review of 44 basic studies in mice

BACKGROUND AND OBJECTIVE

Tolerogenic DCs (Tol-DCs), a group of cells with imDC phenotype, can stably induce T cells low-reactivity and immune tolerance. We systematically reviewed the adoptive transfusion of Tol-DCs induced by different ways to prolong cardiac allograft survival and its possible mechanism.

METHOD

MEDLINE (1966 to March 2011), EMbase (1980 to March 2011), and ISI (inception to March 2011) were searched for identification of relevant studies. We used allogeneic heart graft survival time as endpoint outcome to analyze the effect of adoptive transfusion of Tol-DC on cardiac allograft. By integrating studies' information, we summarized the mechanisms of Tol-DC in prolonging cardiac grafts.

RESULTS

Four methods were used to induce Tol-DC in all of the 44 included studies including gene-modified, drug-intervened, cytokine-induced, and other-derived (liver-derived & spleen-derived) DCs. The results showed that all types of Tol-DC can effectively prolong graft survival, and the average extension of graft survival time for each group was as follows: 22.02 ± 21.9 days (3.2 folds to control group) in the gene modified group, 25.94 ± 16.9 days (4.3 folds) in the drug-intervened groups, 9.00 ± 8.13 days (1.9 folds) in the cytokine-induced group, and 10.69 ± 9.94 days (2.1 folds) in the other-derived group. The main mechanisms of Tol-DCs to prolong graft survival were as follows: (1) induceT-cell hyporeactivity (detected by MLR); (2) reduce the effect of cytotoxic lymphocyte (CTL); (3) promote Th2 differentiation; (4) induce Treg; (5) induce chimerism.

CONCLUSION

For fully MHC mismatched allogeneic heart transplant recipients of inbred mouse, adoptive transfusion of Tol-DC, which can be gene-modified, drug-intervened, cytokine-induced, spleen-derived or liver-derived, can clearly prolong the survival of cardiac allograft or induce immune tolerance. Gene-modified and drug-induced Tol-DC can prolong graft survival most obviously. Having better reliability and stability than drug-induction, gene-modification is the best way to induce Tol-DCs at present. One-time intravenous infusion of 2 × 10(6) Tol-DC is a simple and feasible way to induce long-term graft survival. Multiple infusions will prolong it but increase the risk and cost. Adoptive transfusion of Tol-DC in conjunction with immunosuppressive agents may also prolong the graft survival time.

Enhancement of CTLs induced by DCs loaded with ubiquitinated hepatitis B virus core antigen

AIM: To investigate whether hepatitis B virus (HBV) could induce a hepatitis B virus core antigen (HBcAg)-specific cytotoxic T lymphocyte (CTL) response in vitro by dendritic cells (DCs) transduced with lentiviral vector-encoding ubiquitinated hepatitis B virus core antigen (LV-Ub-HBcAg).

METHODS: Recombinant LV-Ub-HBcAg were transfected into highly susceptible 293 T cells to obtain high virus titres. Bone marrow-derived DCs isolated from BALB/c mice were cultured with recombinant granulocyte-macrophage colony-stimulating factor and recombinant interleukin (IL)-4. LV-Ub-HBcAg, lentiviral vector-encoding hepatitis B virus core antigen (LV-HBcAg), lentiviral vector (LV) or lipopolysaccharide were added to induce DC maturation, and the DC phenotypes were analyzed by flow cytometry. The level of IL-12 in the supernatant was detected by enzyme-linked immunosorbent assay (ELISA). T lymphocytes were proliferated using Cell Counting Kit-8. DCs were cultured and induced to mature using different LVs, and co-cultured with allogeneic T cells to detect the secretion levels of IL-2, IL-4, IL-10 and interferon-γ in the supernatants of T cells by ELISA. Intracellular cytokines of proliferative T cells were analyzed by flow cytometry, and specific CTL activity was measured by a lactate dehydrogenase release assay.

RESULTS: LV-Ub-HBcAg-induced DCs secreted more IL-12 and upregulated the expression of CD80, CD86 and major histocompatibility class II. DCs sensitised by different LVs effectively promoted cytokine secretion; the levels of IL-2 and interferon-γ induced by LV-Ub-HBcAg were higher than those induced by LV-HBcAg. Compared with LV-HBcAg-transduced DCs, LV-Ub-HBcAg-transduced DCs more efficiently stimulated the proliferation of T lymphocytes and generated HBcAg-specific cytotoxic T lymphocytes.

CONCLUSION: LV-Ub-HBcAg effectively induced DC maturation. The mature DCs efficiently induced T cell polarisation to Th1 and generated HBcAg-specific CTLs.

Mechanism of immune hyporesponsiveness induced by recipient- derived immature dendritic cells in liver transplantation rat

OBJECTIVE

To investigate the mechanism of immune hyporesponsiveness induced by donor-antigen- unloaded recipient-derived immature dendritic cell (imDC) of liver grafts in rats.

METHODS

Forty Sprague-Dawley rats (donor) and forty male Wistar rats (recipient) were randomly divided into 4 groups: control, cyclosporine A (CsA), mature DC (mDC), and imDC groups respectively, with 10 donor rats and 10 recipient rats in each group. Recipient rats in CsA group were treated with 10 mg•kg⁻¹•d⁻¹ CsA starting day 2 after the transplantation. Recipients in the mDC or imDC groups were given Wistar rat derived mDCs (1 × 10⁶/rat) or imDCs (1 × 10⁶/rat) via dorsal vein of the penis respectively 1 day before the transplantation. In each group, 5 recipients were kept for determination of survival time and the other 5 rats were executed at day 10 after transplantation. Blood samples were collected for the measurement of serum alanine aminotransferase (ALT), total bilirubin (TBIL), interleukin 2 (IL-2), interferon gamma (IFN-γ), IL-4, and IL-10 levels. Liver tissue was harvested for HE staining and acute rejection evaluation. Expression levels of Fas-L/Fas in the grafts were detected by immunohistochemical staining; and Western blot was used to detect the expression level of Scurfin.

RESULTS

The survival time of CsA and imDC groups was significantly longer than that of control and mDC groups (all P < 0.05). The levels of serum ALT and TBIL in the control group (2072.20 ± 217.93 IU/L and 147.42 ± 22.02 µmol/L) and mDC group (2117.00 ± 285.13 IU/L and 141.58 ± 20.82 µmol/L) were significantly higher than those in the CsA group (59.68 ± 13.48 IU/L and 15.40 ± 2.13 µmol/L) or imDC group (50.80 ± 9.63 IU/L and 14.44 ± 3.49 µmol/L) (all P < 0.05). In the CsA and imDC groups, the levels of IL-2 (22.52 ± 3.75 pg/mL and 22.12 ± 3.90 pg/mL) and IFN-γ (309.20 ± 25.19 pg/mL and 321.00 ± 21.64 pg/mL) were significantly lower, but the levels of IL-4 (297.60 ± 25.07 pg/mL and 277.00 ± 22.47 pg/mL) and IL-10 (1226.00 ± 140.49 pg/mL and 1423.00 ± 106.39 pg/mL) were higher than those of the control (IL-2: 147.78 ± 12.80 pg/mL, IFN-γ: 1758.60 ± 106.22 pg/mL, IL-4: 17.40 ± 4.77 pg/mL, IL-10: 81.00 ± 9.47 pg/mL) and mDC groups (IL-2: 142.34 ± 9.29 pg/mL, IFN-γ: 1835.00 ± 82.63 pg/mL, IL-4: 15.60 ± 3.96 pg/mL, IL-10: 68.80 ± 11.23 pg/mL) (all P < 0.01). The expression level of Scurfin protein on CD4+ CD25+ T cells of the imDC group (1.34 ± 0.29) was significantly higher than that in the control (0.72 ± 0.13), CsA (0.37 ± 0.11), and mDC groups (0.78 ± 0.17) (all P < 0.05).

CONCLUSION

Donor-antigen-unloaded recipient-derived imDC is an effective treatment in inducing immune hyporesponsiveness through induction of T cell apoptosis, shift in Thl/Th2 balance, and proliferation of regulatory T cell.

Emerging applications of lentiviral vectors in dendritic cell-based immunotherapy

Dendritic cells are professional antigen-presenting cells that initiate, regulate and shape the induction of specific immune responses. The ability to use dendritic cells in the induction of antigen-specific tolerance, antigen-specific immunity or specific differentiation of T-helper subsets holds great promise in dendritic cell-based immunotherapy of various diseases such as cancer, viral infections, allergy, as well as autoimmunity. Replication-incompetent HIV-1-based lentiviral vector is now emerging as a promising delivery system to genetically modify dendritic cells through antigen recognition, costimulatory molecules and/or polarization signals for the manipulation of antigen-specific immunity in vivo. This article discusses some of the recent advances in the uses of lentiviral vectors in dendritic cell-based immunotherapy.

Cross-tolerance of recipient-derived transforming growth factor-beta dendritic cells

Administration of donor-derived immature dendritic cells (DC) treated with transforming growth factor-beta (TGF-beta) to prevent allograft rejection is not applicable for clinical use. We therefore attempted to explore the use of recipient-derived DC pulsed with donor antigens via the indirect pathway (cross-priming). DC were propagated from C3H (H2(k)) bone marrow (BM) using granulocyte-macrophage colony stimulating factor (GM-CSF) and interleukin-4 (IL-4). TGF-beta (0.2 ng/mL) was added at the initiation of culture. The resultant TGF-beta DC were pulsed with B10 (H2(b)) splenocyte lysate. Expression of major histocompatibility complex (MHC) class I and II was not affected, while CD40, CD80, and CD86 costimulatory molecules on DC were significantly inhibited by treatment with TGF-beta. C3H DC pulsed with B10 antigens stimulated a proliferative response in C3H T cells which was inhibited when DC were treated with TGF-beta, and the cytotoxic T-lymphocyte (CTL) activity was also inhibited. This observation correlated with reduced interferon-gamma (IFN-gamma) and increased IL-10 production. A single injection of TGF-beta DC prolonged allograft survival (median survival time [MST] 18 days vs 10 days in no-DC treatment control; P < .05). These data indicated that an approach utilizing recipient DC as a "vaccine" strategy is possible.

Prolongation of heart allograft survival by immature dendritic cells generated from recipient type bone marrow progenitors

Recent studies suggest that particular dendritic cells (DC) subpopulations may be tolerogenic. To test the capacity of different DC subpopulations to modulate allograft rejection, we generated two distinct populations of rat bone marrow-derived DCs (BMDC) with low doses of GM-CSF and IL-4. The non-adherent population (nBMDC), which are the 'classical' DCs was able to stimulate naive allogeneic T cells and could be induced to completely mature using various stimuli. In contrast, the adherent population (aBMDC), which displayed an immature phenotype, was unable to stimulate T cells and was more resistant to maturation. We found that syngeneic aBMDCs, injected one day before transplantation, induced significant prolongation of heart allograft survival and decreased anti-donor humoral and cellular responses. Similarly, syngeneic aBMDCs inhibited T-cell responses to KLH in the spleen but not in lymph node in a KLH immunization model without graft. This effect was not antigen specific and could be reversed using an inhibitor of inducible nitric oxide synthase. This compartmentalized inhibition could be in part explained by the fact that the majority of syngeneic adherent cells administered intravenously were found in the spleen with some of them reaching the T-cell areas. These data suggest that syngeneic aBMDCs can modulate immune responses.