Protective role of interleukin-10-producing regulatory dendritic cells against murine autoimmune gastritis

Critical influence of cytokines and immune cells in autoimmune gastritis

Gastric cancer (GC) is a type of the most common cancers. Autoimmune gastritis (AIG) and infection with Helicobacter pylori (HP) are the risk factors of triggering GC. With the emphasis on the treatment of HP, the incidence and prevalence of HP infection in population is decreasing. However, AIG lacks accurate diagnosis and treatment methods, which occupies high cancer risk factors. AIG is controlled by the immune environment of the stomach, including immune cells, inflammatory cells, and infiltrating intercellular material. Various immune cells or cytokines play a central role in the process of regulating gastric parietal cells. Abnormal expression levels of cytokines involved in immunity are bound to face the risk of tumorigenesis. Therefore, it is particularly important for preventing or treating AIG and avoiding the risk of gastric cancer to clarify the confirmed action mode of immune cells and cytokines in the gastric system. Herein, we briefly reviewed the role of the immune environment under AIG, focussing on describing these double-edged effects between immune cells and cytokines, and pointing out potential research challenges.

Dominant trait linked to chromosome 1 in DBA/2 mice for the resistance to autoimmune gastritis appears in bone marrow cells

Neonatal thymectomy (NTx) induces autoimmune gastritis (AIG) in BALB/c mice, a model for human type A chronic atrophic gastritis, but not in DBA/2 mice and rarely in CDF1 mice (a hybrid of BALB/c and DBA/2 mice). The aim of this study was to clarify the mechanisms of AIG-resistance in mice bearing the dominant trait of DBA/2. Linkage groups associated with, and cells related to AIG resistance were examined with CDF1-BALB/c backcrosses. Intracellular staining and flow-cytometric bead array for several cytokines were performed on NTx BALB/c mice and NTx DBA/2-chimeric BALB/c mice receiving DBA/2-bone marrow cells. In NTx BALB/c mice, IFN-γ-secreting CD4(+) T cells were increased, but not in NTx DBA/2 mice. Because Vβ6(+) T cell-bearing mice of half of their backcrosses developed AIG, but the other half of Vβ6(+) T cell-negative mice developed scarcely, resistance for AIG generation is associated with the presence of the Mls-1a locus on chromosome 1 in DBA/2 mice, which deletes Vβ6(+) T cells. NTx DBA/2-chimera BALB/c mice showed dominant production of IL-10 and resistance for AIG, although the deletion of Vβ6(+) T cells was found not to be a cause of AIG-resistance from Mls-1a locus segregation experiments. Although NTx DBA/2-chimeric BALB/c mice did not suffer from AIG, they brought immediate precursors of T cells for AIG. It is concluded that DBA/2 mice generate bone marrow-derived cells that produce anti-inflammatory cytokines to prevent the activation of AIG-T cells.

Dendritic cell therapy for Type 1 diabetes suppression

While dendritic cell-based therapy is a clinical reality for human malignancies, until now, some conceptual concerns have served to delay its consideration to treat human autoimmune diseases, even in light of almost two decades' worth of overwhelmingly supportive preclinical animal studies. This article provides an overview of the development of dendritic cell-based therapy for Type 1 diabetes mellitus, given that this is the best-studied autoimmune disorder and that there is a good understanding of the underlying immunology. This article also highlights data from the authors' pioneering Phase I clinical trial with tolerogenic dendritic cells, which hopes to motivate the clinical translation of other dendritic cell-based approaches, to one or more carefully selected Type 1 diabetic patient populations.

Regulatory dendritic cells in the tumor immunoenvironment

The tumor microenvironment is a pivotal factor in tumorigenesis, and especially in progression, as the pathogenesis of cancer critically depends on the complex interactions between various microenvironmental components. A key component of the tumor immunoenvironment is the infiltration of immune cells, which has been proven to play a dual role in tumor growth and progression. This Janus two-faced function of the tumor immunoenvironment is seen in tumor infiltration by T cells, which correlates with improved patient survival, but also with the homing of multiple subsets of immunoregulatory cells that inhibit the antitumor immune response. Regulatory dendritic cells (regDCs) have recently been shown to be induced by tumor-derived factors and represent a new and potentially important player in supporting tumor progression and suppressing the development of antitumor immune responses. Our recent data reveal that different tumor cell lines produce soluble factors that induce polarization of conventional DCs into regDCs, both in vitro and in vivo. These regDCs can suppress the proliferation of pre-activated T cells and are phenotypically and functionally different from their precursors as well as the classical immature conventional DCs. Understanding the biology of regDCs and the mechanisms of their formation in the tumor immunoenvironment will provide a new therapeutic target for re-polarizing protumorigenic immunoregulatory cells into proimmunogenic effector cells able to induce and support effective antitumor immunity.

Kampo medicine "Dai-kenchu-to" prevents CPT-11-induced small-intestinal injury in rats

PURPOSE

The key anticancer agent, CPT-11 (irinotecan hydrochloride), induces severe diarrhea clinically. We investigated the effect of a Kampo medicine, Dai-kenchu-to (DKT), on CPT-11-induced intestinal injuries in rats.

METHODS

Twenty-four male Wistar rats were divided into three groups: a control group; a CPT-11 group, given CPT-11 150 mg/kg intraperitoneally for 2 days; and a DKT group, given DKT 300 mg/kg orally for 5 days with CPT-11 150 mg/kg intraperitoneally on days 4 and 5. The rats were killed on day 6.

RESULTS

Interleukin (IL)-1β, IL-12, interferon (IFN)-γ, and tumor necrosis factor-α expression in the small intestine of the CPT-11 group was significantly higher than that of the control group. Interleukin-1β and IFN-γ expression was improved significantly by DKT (P < 0.05). The number and height of jejuna villi, injury score, and apoptosis index in the CPT-11 group were improved significantly by DKT (P < 0.05).

CONCLUSIONS

DKT suppressed CPT-11 induced inflammatory cytokines and apoptosis in the intestinal mucosa and maintained the mucosal integrity.

Targeting myeloid regulatory cells in cancer by chemotherapeutic agents

Recent findings in humans and numerous experimental models provide evidence of the important role of immune regulatory cells in cancer and various diseases. "Myeloid regulatory cells" (MRC) include myeloid-derived suppressor cells, regulatory dendritic cells, regulatory macrophages, and subsets of granulocytes that expand during pathologic conditions and that have the ability to suppress cellular immunity. A decrease in MRC population and/or activity has been shown to have positive immune-potentiating effects. Several clinical trials have thus been initiated with the goal of manipulating the expansion or activation of these cells and thereby improving patient immune responses. New data from our own and other laboratories recently revealed that ultralow noncytotoxic doses of certain chemotherapeutic drugs could up-regulate antitumor immunity by modulating the formation, differentiation, and/or function of MRC. This new phenomenon, termed "chemomodulation," allows for the regulation of the tumor microenvironment without the undesirable toxic effects associated with conventional chemotherapy. However, further studies are required before this new targeted therapy can find its way to patients with cancer.

PD-L1 blockade overrides Salmonella typhimurium-mediated diabetes prevention in NOD mice: no role for Tregs

Increasingly, evidence suggests that there is a strong environmental component to the development of the autoimmune disease type 1 diabetes. Our previous data showed that NOD mice are protected from developing diabetes after infection with Salmonella typhimurium and there is some evidence that changes within the DC compartment play a crucial role in this protective effect. This paper further characterises this Salmonella-modulated protective phenotype. We find that, contrary to other infection-mediated models of type 1 diabetes protection, there was no expansion of Foxp3(+) Tregs. Furthermore, transcriptome analysis of DCs identified a distinct Salmonella-induced signature in which the inhibitory receptor PD-L1 was up-regulated. This was confirmed by flow cytometry. In vivo blockade of the PD1/PD-L1 interaction was found to ablate the protective function of Salmonella infection. These data provide evidence for a novel regulatory DC phenotype proficient at controlling autoreactive T cells for an extended duration in the NOD mouse model of diabetes.

Current state of type 1 diabetes immunotherapy: incremental advances, huge leaps, or more of the same?

Thus far, none of the preclinically successful and promising immunomodulatory agents for type 1 diabetes mellitus (T1DM) has conferred stable, long-term insulin independence to diabetic patients. The majority of these immunomodulators are humanised antibodies that target immune cells or cytokines. These as well as fusion proteins and inhibitor proteins all share varying adverse event occurrence and severity. Other approaches have included intact putative autoantigens or autoantigen peptides. Considerable logistical outlays have been deployed to develop and to translate humanised antibodies targeting immune cells, cytokines, and cytokine receptors to the clinic. Very recent phase III trials with the leading agent, a humanised anti-CD3 antibody, call into question whether further development of these biologics represents a step forward or more of the same. Combination therapies of one or more of these humanised antibodies are also being considered, and they face identical, if not more serious, impediments and safety issues. This paper will highlight the preclinical successes and the excitement generated by phase II trials while offering alternative possibilities and new translational avenues that can be explored given the very recent disappointment in leading agents in more advanced clinical trials.

Frequency of CD45RO+ subset in CD4+CD25(high) regulatory T cells associated with progression of hepatocellular carcinoma

The purpose of this study was to assess the properties of CD4+CD25(high/low/negative) T cell subsets and analyze their relation with dendritic cells (DCs) in patients with hepatocellular carcinoma (HCC). In HCC patients, the prevalence of CD45RO+ cells in CD4+CD25(high) T cells was increased and associated with higher frequencies of plasmacytoid DCs. Larger proportions of this T cell subset were detected in the patients with larger tumor burdens. These results suggest that increased frequencies of the CD45RO+ subset in CD4+CD25(high) Tregs in HCC patients may establish the immunosuppressive environment cooperatively with tolerogenic plasmacytoid DCs to promote disease progression of liver cancer.

Dendritic cell-based therapy in Type 1 diabetes mellitus

Dendritic cell (DC) immunotherapy is a clinical reality. Despite two decades of considerable data demonstrating the feasibility of using DCs to prolong transplant allograft survival and to prevent autoimmunity, only now are these cells entering clinical trials in humans. Type 1 diabetes is the first autoimmune disorder to be targeted for treatment in humans using autologous-engineered DCs. This review will highlight the role of DCs in autoimmunity and the manner in which they have been engineered to treat these disorders in rodent models, either via the induction of immune hyporesponsiveness, which may be cell- and/or antigen-specific, or indirectly by upregulation of other immune cell networks.