Therapeutic Antitumor Efficacy of Cancer Stem Cell-Derived DRibble Vaccine on Colorectal Carcinoma

Dendritic cell (DC)-based immunotherapy has been a promising strategy for colon cancer therapy, but the efficacy of dendritic cell vaccines is in part limited by immunogenicity of loaded antigens. In this study, we aimed to identify a putative tumor antigen that can generate or enhance anti-tumor immune responses against colon cancer. CD44⁺ colon cancer stem cells (CCSCs) were isolated from mouse colorectal carcinoma CT-26 cell cultures and induced to form defective ribosomal products-containing autophagosome-rich blebs (DRibbles) by treatment with rapamycin, bortezomib, and ammonium chloride. DRibbles were characterized by western blot and transmission electron microscopy. DCs generated from the mice bone marrow monocytes were cocultured with DRibbles, then surface markers of DCs were analyzed by flow cytometry. Meanwhile, the efficacy of DRibble-DCs was examined in vivo. Our results showed that CCSC-derived DRibbles upregulated CD80, CD86, major histocompatibility complex (MHC)-I, and MHC-II on DCs and induced proliferation of mouse splenic lymphocytes and CD8⁺ T cells. In a model of colorectal carcinoma using BALB/c mice with robust tumor growth and mortality, DC vaccine pulsed with CCSC-derived DRibbles suppressed tumor growth and extended survival. A lactate dehydrogenase test indicated a strong cytolytic activity of cytotoxic T-cells derived from mice vaccinated with CCSC-derived DRibbles against CT-26 cells. Furthermore, flow cytometry analyses showed that the percentages of IFN-γ-producing CD8⁺ T-cells were increased in SD-DC group compare with the other groups. These findings provide a rationale for novel immunotherapeutic anti-tumor approaches based on DRibbles derived from colon cancer stem cells.     

Gastrointestinal disease in simian immunodeficiency virus-infected rhesus macaques is characterized by proinflammatory dysregulation of the interleukin-6-Janus kinase/signal transducer and activator of transcription3 pathway

Gastrointestinal disease and inflammation are common sequelae of human and simian immunodeficiency virus (SIV) infection. Nevertheless, the molecular mechanisms that lead to gastrointestinal dysfunction remain unclear. We investigated regulation of the interleukin (IL)-6-JAK-STAT3 pathway in jejunum and colon, collected at necropsy, from 10 SIV-infected macaques with diarrhea (group 1), 10 non-SIV-infected macaques with diarrhea (group 2), and 7 control uninfected macaques (group 3). All group 1 and 2 macaques had chronic diarrhea, wasting, and colitis, but group 1 animals had more frequent and severe lesions in the jejunum. A significant increase in IL-6 and SOCS-3 gene expression along with constitutive STAT3 activation was observed in the colon of all group 1 and 2 macaques and in the jejunum of only group 1 macaques compared to controls. Further, in colon, histopathology severity scores correlated significantly with IL-6 (groups 1 and 2) and SOCS-3 (group 2) gene expression. In jejunum, a similar correlation was observed only in group 1 animals. Phosphorylated STAT3 (p-STAT3) was localized to lymphocytes (CD3+) and macrophages (CD68+), with fewer CD3+ lymphocytes expressing p-STAT3 in group 1 macaques. Despite high SOCS-3 expression, STAT3 remained constitutively active, providing a possible explanation for persistent intestinal inflammation and immune activation that may favor viral replication and disease pro-gression.     

自体DC治疗对大肠癌术后患者免疫功能的影响

目的探讨热休克凋亡的人自体大肠癌细胞致敏的树突状细胞（DC）疫苗对大肠癌术后免疫功能的影响。方法从大肠癌患者外周血单核细胞中诱导DC，并用重组人粒细胞-噬细胞集落刺激因子（rhGM-CSF）和白介素4（IL-4）刺激活化，经热休克凋亡自体大肠癌细胞致敏制备DC疫苗。将26例大肠癌术后患者随机分为DC疫苗治疗组13例，化疗对照组13例。对两组病例治疗前后免疫功能、临床疗效进行观察比较。结果DC疫苗治疗后外周血CD3^＋、CD4^＋／CD8^＋及NK细胞比率较治疗前明显升高，P〈0．05，且明显高于对照组化疗后的CD3^＋、CD4^＋／CD8^＋及NK细胞比率，P〈0．05；DC疫苗治疗后血清IL-2／IL-12／IFN-r水平较治疗前明显升高，P〈0．05，且明显高于对照组化疗组，P〈0．05。结论大肠癌术后行热休克凋亡自体大肠癌细胞致敏的DC疫苗治疗，可改善患者的细胞免疫水平，且不良反应少，值得推广应用。     

Induction of type I interferon signaling by Pseudomonas aeruginosa is diminished in cystic fibrosis epithelial cells

The clinical manifestations of infection in cystic fibrosis (CF) are restricted to the lung, and involve a limited number of pathogens, suggesting a specific defect in mucosal immunity. We postulated that cystic fibrosis transmembrane conductance regulator (CTFR) mutations could affect the activation of type I interferon signaling in airway epithelial cells, which function in immune surveillance and initiate the recruitment and activation of immune cells. In response to infection with Pseudomonas aeruginosa, Ifnb was induced more than 100-fold in the murine lung, and the phosphorylation of STAT1 was similarly induced by the expected TLR4/TRIF/MD2/TBK1 cascade. The stimulation by P. aeruginosa of CF (IB3) cells and control (C-38) human cell lines similarly resulted in the induction of IFN-β, but to a significantly lower extent in CF airway cells. The potential consequences of diminished type I IFN signaling were demonstrated in a murine model of P. aeruginosa pneumonia, pretreatment with polyinosinic:polycytidylic acid significantly enhanced bacterial clearance and correlated with increased numbers of mature CD11c(+)/CD86(+) dendritic cells (DCs) in the lung. Using culture supernatants from CF or control cell lines stimulated with P. aeruginosa, we similarly demonstrated the diminished activation of human monocyte-derived DCs by incubation with CF compared with normal epithelial cell culture supernatants, which was dependent on IFN-β. These observations suggest that dysfunction of the CFTR in airway epithelial cells may contribute to impaired immune surveillance in the CF airway and resultant colonization by P. aeruginosa.     

IL-6-STAT3 controls intracellular MHC class II alphabeta dimer level through cathepsin S activity in dendritic cells

We found IL-6-STAT3 pathway suppresses MHC class II (MHCII) expression on dendritic cells (DCs) and attenuates T cell activation. Here, we showed that IL-6-STAT3 signaling reduced intracellular MHCII alphabeta dimmer, Ii, and H2-DM levels in DCs. IL-6-mediated STAT3 activation decreased cystatin C level, an endogenous inhibitor of cathepsins, and enhanced cathepsin activities. Importantly, cathepsin S inhibitors blocked reduction of MHCII alphabeta dimer, Ii, and H2-DM in the IL-6-treated DCs. Overexpression of cystatin C suppressed IL-6-STAT3-mediated increase of cathepsin S activity and reduction of MHCII alphabeta dimer, Ii, and H2-DM levels in DCs. Cathepsin S overexpression in DCs decreased intracellular MHCII alphabeta dimer, Ii, and H2-DM levels, LPS-mediated surface expression of MHCII and suppressed CD4(+) T cell activation. IL-6-gp130-STAT3 signaling in vivo decreased cystatin C expression and MHCII alphabeta dimer level in DCs. Thus, IL-6-STAT3-mediated increase of cathepsin S activity reduces the MHCII alphabeta dimer, Ii, and H2-DM levels in DCs, and suppresses CD4(+) T cell-mediated immune responses.     

A novel nanoparticle containing MOG peptide with BTLA induces T cell tolerance and prevents multiple sclerosis

Accumulative evidence demonstrates that multiple sclerosis (MS) is caused by activation of myelin Ag-reactive CD4+ T cells. Therefore, the CD4+ T cells specific for myelin Ag may be the important therapeutical target of MS. The novel coinhibitory receptor B and T lymphocyte attenuator (BTLA) may have a regulatory role in maintaining peripheral tolerance, however, its role in MS is still unknown. In this study, a novel nanoparticle containing MOG peptide with BTLA was designed and transduced into dendritic cells (DCs), and MOG peptide-induced EAE mice were adminstrated with the genetically modified DCs in vivo. The results demonstrated that modified DCs significantly enhanced the proportion of Foxp3+ CD4+ regulatory T cells, increased IL-10 and TGF-β cytokine secretion, while decreased IL-2 and IFN-γ cytokine secretion. Furthermore, modified DCs supressed the CD4+ T cell response to MOG, cell infiltration into spinal cord, and the severity of EAE. In contrast, immune response to irrelevant exogenous Ag was not impaired by treatment with modified DCs. These findings suggested that DCs transduced with nanoparticle could induce specific CD4+ T-cells tolerance, which provided a promising therapeutic means to negatively manipulate immune response for autoimmune diseases without inhibition of the immune response to irrelevant Ag.     

Campylobacter jejuni induces maturation and cytokine production in human dendritic cells

Campylobacter jejuni is a leading bacterial cause of human diarrheal disease in both developed and developing nations. Colonic mucosal invasion and the resulting host inflammatory responses are thought to be the key contributing factors to the dysenteric form of this disease. Dendritic cells (DCs) play an important role in both the innate and adaptive immune responses to microbial infection. In this study, the interaction between human monocyte-derived dendritic cells and C. jejuni was studied. We found that C. jejuni was readily internalized by DCs over a 2-h period. However, after a prolonged infection period (24 or 48 h) with C. jejuni, only a few viable bacteria remained intracellularly. Minimal cytotoxicity of C. jejuni to dendritic cells was observed. C. jejuni induced the maturation of dendritic cells over 24 h, as indicated by up-regulation of cell surface marker proteins CD40, CD80, and CD86. In addition, Campylobacter-infected DCs triggered activation of NF-kappaB and significantly stimulated production of interleukin-1beta (IL-1beta), IL-6, IL-8, IL-10, IL-12, gamma interferon, and tumor necrosis factor alpha (TNF-alpha) compared to uninfected DCs. Active bacterial invasion of DCs was not necessary for the induction of these cytokines, as heat-killed C. jejuni stimulated similar levels of cytokine production as live bacteria. Purified lipooligosaccharide of C. jejuni appears to be the major stimulant for the increased production of cytokines by DCs. Taken together, these data indicate that during infection, Campylobacter triggers an innate inflammatory response through increased production of IL-1beta, IL-6, IL-8, and TNF-alpha and initiates a Th1-polarized adaptive immune response as predicted from the high level of production of IL-12.     

Colonic tolerance develops in the iliac lymph nodes and can be established independent of CD103+ dendritic cells

Tolerance to harmless exogenous antigens is the default immune response in the gastrointestinal tract. Although extensive studies have demonstrated the importance of the mesenteric lymph nodes (MLNs) and intestinal CD103⁺ dendritic cells (DCs) in driving small intestinal tolerance to protein antigen, the structural and immunological basis of colonic tolerance remain poorly understood. We show here that the caudal and iliac lymph nodes (ILNs) are inductive sites for distal colonic immune responses and that colonic T cell-mediated tolerance induction to protein antigen is initiated in these draining lymph nodes and not in MLNs. In agreement, colonic tolerance induction was not altered by mesenteric lymphadenectomy. Despite tolerance development, CD103⁺CD11b⁺ DCs, which are the major migratory DC population in the MLNs, and the tolerance-related retinoic acid-generating enzyme RALDH2 were virtually absent from the ILNs. Administration of ovalbumin (OVA) to the distal colon did increase the number of CD11c⁺MHCII^hi migratory CD103⁻CD11b⁺ and CD103⁺CD11b⁻ DCs in the ILNs. Strikingly, colonic tolerance was intact in Batf3-deficient mice specifically lacking CD103⁺CD11b⁻ DCs, suggesting that CD103⁻ DCs in the ILNs are sufficient to drive tolerance induction after protein antigen encounter in the distal colon. Altogether, we identify different inductive sites for small intestinal and colonic T-cell responses and reveal that distinct cellular mechanisms are operative to maintain tolerance at these sites.     

通过肿瘤致敏的DCs活化的CD8+ T细胞可有效地杀死肿瘤细胞

目的：探索肿瘤裂解物负载的DCs诱导活化的初始T细胞介导细胞免疫及活化的T细胞杀死肿瘤细胞的能力。方法:应用黏附法分离外周血中的淋巴细胞和单核细胞,应用GM-CSF+IL-4刺激单核细胞并诱导为iDCs,然后进行分组，应用相应的细胞因子等刺激iDCs转化为mDCs,其中肿瘤裂解物冲击DCs组:冻融抗原负载+TNF-α+IL-1β; 无肿瘤裂解物冲击组: TNF-α+IL-1β。再分别用上述DCs与淋巴细胞进行混合培养以刺激混合淋巴细胞中的T细胞转化为细胞毒性T细胞, 并进行分组, 肿瘤裂解物冲击DCs组: 肿瘤裂解物冲击DCs+IL-2+IL-7；无肿瘤裂解物冲击DCs组: 无肿瘤裂解物冲击DCs+IL-2+IL-7；对照组: IL-2+IL-7。结果:成功获得iDCs,并高表达CD86、CD80和HLA-DR；相对于其它组，肿瘤裂解物冲击DCs组mDCs更显著上调CD83，且更有效地刺激淋巴细胞增殖； 肿瘤裂解物冲击DCs组的CTLs也高表达CD95(Fas)且TNF-α和IFN-γ的表达水平显著提高(P<0.05)。结论: 肿瘤裂解物冲击DCs可有效促进T细胞活化、增殖；并显著增强相应CTLs的杀死靶细胞的能力，这为发展DCs+CTLs的免疫治疗肿瘤提供了一种新而且简便的生物治疗模式。