In an effort to raise protective antiviral immunity, dendritic cell immunotherapy was evaluated in six adults infected with human immunodeficiency virus (HIV)-1 and stable under highly active ...antiretroviral therapy (HAART).
Autologous monocyte-derived dendritic cells electroporated with mRNA encoding Gag and a chimeric Tat-Rev-Nef protein were administered, whereas patients remained on HAART. Feasibility, safety, immunogenicity and antiviral responses were investigated.
Dendritic cell vaccine preparation and administration were successful in all patients and only mild adverse events were seen. There was a significant increase post-dendritic cell as compared to pre-dendritic cell vaccination in magnitude and breadth of HIV-1-specific interferon (IFN)-γ response, in particular to Gag, and in T-cell proliferation. Breadth of IFN-γ response and T-cell proliferation were both correlated with CD4(+) and CD8(+) polyfunctional T-cell responses. Importantly, dendritic cell vaccination induced or increased the capacity of autologous CD8(+) T cells to inhibit superinfection of CD4(+) T cells with the vaccine-related IIIB virus and some but not all other HIV-1 strains tested. This HIV-1-inhibitory activity, indicative of improved antiviral response, was correlated with magnitude and breadth of Gag-specific IFN-γ response.
Therapeutic immunization with dendritic cells was safe and successful in raising antiviral cellular immune responses, including effector CD8(+) T cells with virus inhibitory activity. The stimulation of those potent immunological and antiviral effects, which have been associated with control of HIV-1, underscores the potential of dendritic cell vaccination in the treatment of HIV-1. The incomplete nature of the response in some patients helped to identify potential targets for future improvement, that is increasing antigenic spectrum and enhancing T-cell response.
Cellular therapies with CD4+ T regulatory cells (Tregs) hold promise of efficacious treatment for the variety of autoimmune and allergic diseases as well as posttransplant complications. ...Nevertheless, current manufacturing of Tregs as a cellular medicinal product varies between different laboratories, which in turn hampers precise comparisons of the results between the studies performed. While the number of clinical trials testing Tregs is already substantial, it seems to be crucial to provide some standardized characteristics of Treg products in order to minimize the problem. We have previously developed reporting guidelines called minimum information about tolerogenic antigen-presenting cells, which allows the comparison between different preparations of tolerance-inducing antigen-presenting cells. Having this experience, here we describe another minimum information about Tregs (MITREG). It is important to note that MITREG does not dictate how investigators should generate or characterize Tregs, but it does require investigators to report their Treg data in a consistent and transparent manner. We hope this will, therefore, be a useful tool facilitating standardized reporting on the manufacturing of Tregs, either for research purposes or for clinical application. This way MITREG might also be an important step toward more standardized and reproducible testing of the Tregs preparations in clinical applications.
Dendritic cell-based cancer gene therapy Smits, Evelien L J M; Anguille, Sébastien; Cools, Nathalie ...
Human gene therapy,
10/2009, Letnik:
20, Številka:
10
Journal Article
Recenzirano
In view of their potent antigen-presenting capacity and ability to induce effective immune responses, dendritic cells (DCs) have become an attractive target for therapeutic manipulation of the immune ...system. The application of tumor-associated antigen (TAA)-expressing DCs for cancer therapy has been the subject of intensive translational investigation. Previous clinical trials demonstrated tumor-specific immune responses without any significant toxicity. However, the clinical success has been modest, because only a limited number of immunized patients demonstrated cancer regression. Considerable progress has been made in the knowledge of DC biology, which opens new avenues for the development of optimized clinical protocols. One such promising approach that might carve its place in the future of DC-based therapy is the use of gene-modified DCs. DCs engineered to express TAAs allow multiepitope presentation by both major histocompatibility complex (MHC) class I and II molecules of full-length TAAs independent of the patient's HLA constitution, as opposed to peptide vaccination strategies. Besides transgene TAA expression, DCs can be genetically modified (1) to express a variety of immune-potentiating molecules (e.g., costimulatory molecules, cytokines, and chemokines) or (2) to downregulate negative modulators of DC functioning, all allowing an enhancement of their immunogenic potential. In the present review, gene delivery systems for DCs are discussed, as well as the various transgenes used for genetic modification of DCs. Moreover, a detailed review of the already published trials using gene-modified DCs is presented and future DC-based strategies targeting multiple layers of the complex cellular immune response are highlighted.
Abstract
Background
Intestinal dendritic cells (
DC
s) maintain immune homeostasis, only initiating an active immune response against invading pathogens. However, little information is available on ...the reaction of mononuclear phagocytes (
MNP
) to intestinal trematode infection, a reaction equally important in helminth‐based therapies. The
CD
11c
+
CX
3
CR
1
+
F4/80
−
DC
s in the ileal lamina propria (
LP
) of the mouse were proven to migrate to the mesenteric lymph nodes (
MLN
s). We analyzed all
MNP
subsets present in the mouse
LP
and
MLN
s, under steady‐state conditions and during acute
Schistosoma mansoni
‐induced inflammation. Furthermore, we studied the uptake of schistosomal antigens by
MNP
in vivo
in the
LP
and
MLN
s.
Methods
Using a combination of immunohistochemistry and multiparametric flow cytometry, we investigated distributional changes of the
MNP
during acute intestinal schistosomiasis. Next,
S. mansoni
‐derived products, i.e.,
S. mansoni
soluble worm proteins (Sm
SWP
) and
S. mansoni
soluble egg antigens (Sm
SEA
) were intraperitoneally injected into
CX
3
CR
1
+/
GFP
C57BL/6 mice and antigen uptake was analyzed using confocal microscopy.
Key Results
The
CD
11c
+
CX
3
CR
1
+
F4/80
−
DC
s significantly increased during intestinal schistosomiasis in the
LP
and
MLN
s. Only
CX
3
CR
1‐expressing
DC
and MФ subsets, but not other
LP DC
s, are involved in both Sm
SWP
and Sm
SEA
antigen uptake and processing.
Conclusions & inferences
The significant upregulation of
CD
11c
+
CX
3
CR
1
+
F4/80
−
DC
s during intestinal schistosomiasis and the restriction of phagocytosis of parasitic antigens to
CX
3
CR
1‐expresssing
MNP
indicate a crucial role for this immune cell niche in response to trematodiasis. These findings add insight into the functional specialization of
LP
immune cells and add to the understanding of cellular mechanisms behind helminth‐based therapies.
Cashew crops-an important source of foreign exchange in Tanzania-require treatment with sulfur to control powdery mildew, but sulfur acidifies the soil, creating concern about sustainable production ...of cashew and intercropped food crops. The buffering capacity of surface and subsurface horizons in 35 soils of major cashew growing areas was studied. Buffering capacity was weakly correlated with organic carbon content, and with total exchangeable bases and available phosphorus in the surface horizon. Buffering capacity was strongly correlated with clay content and with soil pH, base saturation, and cation exchange capacity of the clay fraction of the subsurface horizon. Buffering capacity differences among the soils tested are summarized. The risk of high acidification and declining cashew and food crop production is greatest on the Makonde plateau, where highly weathered, sandy soils dominate. Treatment to reduce use of sulfur is needed.
Dendritic cells (DC) are professional Ag-capturing and -presenting cells of the immune system. Because of their exceptional capability of activating tumor-specific T cells, cancer vaccination ...research is now shifting toward the formulation of a clinical human DC vaccine. We developed a short term and serum-free culture protocol for rapid generation of fully mature, viable, and highly stimulatory CD83(+) DC. Human monocytes were cultured for 24 h in serum-free AIM-V medium, followed by 24-h maturation by polyriboinosinic polyribocytidylic acid (polyI:C). Short term cultured, polyI:C-maturated DC, far more than immature DC, showed typical mature DC markers and high allogeneic stimulatory capacity and had high autologous stimulatory capacity in an influenza model system using peptide-pulsed DC. Electroporation of mRNA as an Ag-loading strategy in these cells was optimized using mRNA encoding the enhanced green fluorescent protein (EGFP). Monocytes electroporated with EGFP mRNA, followed by short term, serum-free differentiation to mature DC, had a phenotype of DC, and all showed positive EGFP fluorescence. Influenza matrix protein mRNA-electroporated monocytes cultured serum-free and maturated with polyI:C showed high stimulatory capacity in autologous T cell activation experiments. In conclusion, the present short term and serum-free ex vivo DC culture protocol in combination with mRNA electroporation at the monocyte stage imply an important reduction in time and consumables for preparation of Ag-loaded mature DC compared with classical DC culture protocols and might find application in clinical immunotherapy settings.
Dendritic cells (DC) have important functions in T cell immunity and T cell tolerance. Previously, it was believed that T cell unresponsiveness induced by immature DC (iDC) is caused by the absence ...of inflammatory signals in steady-state in vivo conditions and by the low expression levels of costimulatory molecules on iDC. However, a growing body of evidence now indicates that iDC can also actively maintain peripheral T cell tolerance by the induction and/or stimulation of regulatory T cell populations. In this study, we investigated the in vitro T cell stimulatory capacity of iDC and mature DC (mDC) and found that both DC types induced a significant increase in the number of transforming growth factor (TGF)-β and interleukin (IL)-10 double-positive CD4... T cells within 1 week of autologous DC/T cell co-cultures. In iDC/T cell cultures, where antigen-specific T cell priming was significantly reduced as compared to mDC/T cell cultures, we demonstrated that the tolerogenic effect of iDC was mediated by soluble TGF-β and IL-10 secreted by CD4...CD25...FOXP3... T cells. In addition, the suppressive capacity of CD4... T cells conditioned by iDC was transferable to already primed antigen-specific CD8... T cell cultures. In contrast, addition of CD4... T cells conditioned by mDC to primed antigen-specific CD8... T cells resulted in enhanced CD8... T cell responses, notwithstanding the presence of TGF-β.../IL-10... T cells in the transferred fraction. In summary, we hypothesize that DC have an active role in inducing immunosuppressive cytokine-secreting regulatory T cells. We show that iDC-conditioned CD4... T cells are globally immunosuppressive, while mDC induce globally immunostimulatory CD4... T cells. Furthermore, TGF-β+/IL-10... T cells are expanded by DC independent of their maturation status, but their suppressive function is dependent on immaturity of DC. (ProQuest: ... denotes formulae/symbols omitted.)
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