Th17 and Th17-stimulated CD8<Superscript>+</Superscript> T cells play a distinct role in Th17-induced preventive and therapeutic antitumor immunity

CD4⁺ Th17 cells induce antitumor immunity leading to the eradication of established tumors. However, the mechanism of antitumour immunity and CTL activation by Th17 cells and the distinct role of Th17 and Th17-activated CTLs in antitumor immunity are still elusive. In this study, we generated ovalbumin (OVA)-specific Th17 cells by cultivating OVA-pulsed dendritic cells with CD4⁺ T cells derived from transgenic OTII mice in the presence of IL-6, IL-23, TGF-β, and anti-IFN-γ antibody. We demonstrated that Th17 cells acquired major histocompatibility complex/peptide (pMHC)-I and expressed RORγt, IL-17, and IL-2. Th17 cells did not have any direct in vitro tumor cell–killing activity. However, Th17 cells were able to stimulate CD8⁺ CTL responses via IL-2 and pMHC I, but not IL-17 signaling, which play a major role in Th17-induced preventive immunity against OVA-expressing B16 melanoma. Th17 cells stimulated the expression of CCL2 and CCL20 in lung tumor microenvironments promoting the recruitment of various inflammatory leukocytes (DCs, CD4⁺, and CD8⁺ T cells) stimulating more pronounced therapeutic immunity for early-stage (5-day lung metastases or 3 mm, s.c.) tumor than for well-established (6 mm, s.c.) tumor. The therapeutic effect of Th17 cells is associated with IL-17 and is mediated by Th17-stimulated CD8⁺ CTLs and other inflammatory leukocytes recruited into B16 melanoma via Th17-stimulated CCL20 chemoattraction. Taken together, our data elucidate a distinct role of Th17 and Th17-stimulated CD8⁺ CTLs in the induction of preventive and therapeutic antitumor immunity, which may greatly impact the development of Th17-based cancer immunotherapy.     

The p50 Subunit of NF-κB Orchestrates Dendritic Cell Lifespan and Activation of Adaptive Immunity

Dendritic cells play a central role in keeping the balance between immunity and immune tolerance. A key factor in this equilibrium is the lifespan of DC, as its reduction restrains antigen availability leading to termination of immune responses. Here we show that lipopolysaccharide-driven DC maturation is paralleled by increased nuclear levels of p50 NF-κB, an event associated with DC apoptosis. Lack of p50 in murine DC promoted increased lifespan, enhanced level of maturation associated with increased expression of the proinflammatory cytokines IL-1, IL-18 and IFN-β, enhanced capacity of activating and expanding CD4⁺ and CD8⁺ T cells in vivo and decreased ability to induce differentiation of FoxP3⁺ regulatory T cells. In agreement, vaccination of melanoma-bearing mice with antigen-pulsed LPS-treated p50^−/− BM-DC boosted antitumor immunity and inhibition of tumor growth. We propose that nuclear accumulation of the p50 NF-κB subunit in DC, as occurring during lipopolysaccharide-driven maturation, is a homeostatic mechanism tuning the balance between uncontrolled activation of adaptive immunity and immune tolerance.     

ERK5 modulates IL-6 secretion and contributes to tumor-induced immune suppression

Tumors exhibit a variety of strategies to dampen antitumor immune responses. With an aim to identify factors that are secreted from tumor cells, we performed an unbiased mass spectrometry-based secretome analysis in lung cancer cells. Interleukin-6 (IL-6) has been identified as a prominent factor secreted by tumor cells and cancer-associated fibroblasts isolated from cancer patients. Incubation of dendritic cell (DC) cultures with tumor cell supernatants inhibited the production of IL-12p70 in DCs but not the surface expression of other activation markers which is reversed by treatment with IL-6 antibody. Defects in IL-12p70 production in the DCs inhibited the differentiation of Th1 but not Th2 and Th17 cells from naïve CD4⁺ T cells. We also demonstrate that the classical mitogen-activated protein kinase, ERK5/MAPK7, is required for IL-6 production in tumor cells. Inhibition of ERK5 activity or depletion of ERK5 prevented IL-6 production in tumor cells, which could be exploited for enhancing antitumor immune responses.Subject terms: Cancer microenvironment, Extracellular signalling molecules     

IL-10 Conditioning of Human Skin Affects the Distribution of Migratory Dendritic Cell Subsets and Functional T Cell Differentiation

In cancer patients pervasive systemic suppression of Dendritic Cell (DC) differentiation and maturation can hinder vaccination efficacy. In this study we have extensively characterized migratory DC subsets from human skin and studied how their migration and T cell-stimulatory abilities were affected by conditioning of the dermal microenvironment through cancer-related suppressive cytokines. To assess effects in the context of a complex tissue structure, we made use of a near-physiological skin explant model. By 4-color flow cytometry, we identified migrated Langerhans Cells (LC) and five dermis-derived DC populations in differential states of maturation. From a panel of known tumor-associated suppressive cytokines, IL-10 showed a unique ability to induce predominant migration of an immature CD14⁺CD141⁺DC-SIGN⁺ DC subset with low levels of co-stimulatory molecules, up-regulated expression of the co-inhibitory molecule PD-L1 and the M2-associated macrophage marker CD163. A similarly immature subset composition was observed for DC migrating from explants taken from skin overlying breast tumors. Whereas predominant migration of mature CD1a⁺ subsets was associated with release of IL-12p70, efficient Th cell expansion with a Th1 profile, and expansion of functional MART-1-specific CD8⁺ T cells, migration of immature CD14⁺ DDC was accompanied by increased release of IL-10, poor expansion of CD4⁺ and CD8⁺ T cells, and skewing of Th responses to favor coordinated FoxP3 and IL-10 expression and regulatory T cell differentiation and outgrowth. Thus, high levels of IL-10 impact the composition of skin-emigrated DC subsets and appear to favor migration of M2-like immature DC with functional qualities conducive to T cell tolerance.     

A polysaccharide extracted from Grifola frondosa enhances the anti-tumor activity of bone marrow-derived dendritic cell-based immunotherapy against murine colon cancer

We previously isolated the novel heteropolysaccharide maitake Z-fraction (MZF) from the maitake mushroom (Grifola frondosa), and demonstrated that MZF significantly inhibited tumor growth by inducing cell-mediated immunity. In this study, we demonstrated that MZF upregulated the expression of CD80, CD86, CD83, and MHC II on bone marrow-derived dendritic cells (DCs) and significantly increased interleukin-12 (IL-12) and tumor necrosis factor-alpha production by DCs in a dose-dependent manner. MZF-treated DCs significantly stimulated both allogeneic and antigen-specific syngenic T cell responses and enhanced antigen-specific interferon-gamma (IFN-γ) production by syngenic CD4⁺ T cells; however, MZF-treated DCs did not affect IL-4 production. Furthermore, the enhancement of IFN-γ production in CD4⁺ T cells, which was induced by MZF-treated DCs, was completely inhibited by the addition of an anti-IL-12 antibody. These results indicate that MZF induced DC maturation and antigen-specific Th1 response by enhancing DC-produced IL-12. We also demonstrated that DCs pulsed with colon-26 tumor lysate in the presence of MZF induced both therapeutic and preventive effects on colon-26 tumor development in BALB/c mice. These results suggest that MZF could be a potential effective adjuvant to enhance immunotherapy using DC-based vaccination.     

The Mycobacterium avium subsp. Paratuberculosis protein MAP1305 modulates dendritic cell-mediated T cell proliferation through Toll-like receptor-4

In this study, we show that Mycobacterium avium subsp. Paratuberculosis MAP1305 induces the maturation of bone marrow-derived dendritic cells (BMDCs), a representative antigen presenting cell (APC). MAP1305 protein induces DC maturation and the production of pro-inflammatory cytokines (Interleukin (IL)-6), tumor necrosis factor (TNF)-α, and IL-1β) through Toll like receptor-4 (TLR-4) signaling by directly binding with TLR4. MAP1305 activates the phosphorylation of MAPKs, such as ERK, p38MAPK, and JNK, which is essential for DC maturation. Furthermore, MAP1305-treated DCs transform naïve T cells to polarized CD4⁺ and CD8⁺ T cells, thus indicating a key role for this protein in the Th1 polarization of the resulting immune response. Taken together, M. avium subsp. Paratuberculosis MAP1305 is important for the regulation of innate immune response through DC-mediated proliferation of CD4⁺ and CD8⁺ T cells. [BMB Reports 2014; 47(2): 115-120]     

Helminth Infections Coincident with Active Pulmonary Tuberculosis Inhibit Mono- and Multifunctional CD4+ and CD8+ T Cell Responses in a Process Dependent on IL-10

Tissue invasive helminth infections and tuberculosis (TB) are co-endemic in many parts of the world and can trigger immune responses that might antagonize each other. We have previously shown that helminth infections modulate the Th1 and Th17 responses to mycobacterial-antigens in latent TB. To determine whether helminth infections modulate antigen-specific and non-specific immune responses in active pulmonary TB, we examined CD4⁺ and CD8⁺ T cell responses as well as the systemic (plasma) cytokine levels in individuals with pulmonary TB with or without two distinct helminth infections—Wuchereria bancrofti and Strongyloides stercoralis infection. By analyzing the frequencies of Th1 and Th17 CD4⁺ and CD8⁺ T cells and their component subsets (including multifunctional cells), we report a significant diminution in the mycobacterial–specific frequencies of mono- and multi–functional CD4⁺ Th1 and (to a lesser extent) Th17 cells when concomitant filarial or Strongyloides infection occurs. The impairment in CD4⁺ and CD8⁺ T cell cytokine responses was antigen-specific as polyclonal activated T cell frequencies were equivalent irrespective of helminth infection status. This diminution in T cell responses was also reflected in diminished circulating levels of Th1 (IFN-γ, TNF-α and IL-2)- and Th17 (IL-17A and IL-17F)-associated cytokines. Finally, we demonstrate that for the filarial co-infections at least, this diminished frequency of multifunctional CD4⁺ T cell responses was partially dependent on IL-10 as IL-10 blockade significantly increased the frequencies of CD4⁺ Th1 cells. Thus, co-existent helminth infection is associated with an IL-10 mediated (for filarial infection) profound inhibition of antigen-specific CD4⁺ T cell responses as well as protective systemic cytokine responses in active pulmonary TB.     

IL-17 Induction by ArtinM is Due to Stimulation of IL-23 and IL-1 Release and/or Interaction with CD3 in CD4+ T Cells

ArtinM is a D-mannose-binding lectin extracted from the seeds of Artocarpus heterophyllus that interacts with TLR2 N-glycans and activates antigen-presenting cells (APCs), as manifested by IL-12 production. In vivo ArtinM administration induces Th1 immunity and confers protection against infection with several intracellular pathogens. In the murine model of Candida albicans infection, it was verified that, in addition to Th1, ArtinM induces Th17 immunity manifested by high IL-17 levels in the treated animals. Herein, we investigated the mechanisms accounting for the ArtinM-induced IL-17 production. We found that ArtinM stimulates the IL-17 production by spleen cells in BALB/c or C57BL/6 mice, a response that was significantly reduced in the absence of IL-23, MyD88, or IL-1R. Furthermore, we showed that ArtinM directly induced the IL-23 mRNA expression and the IL-1 production by macrophages. Consistently, in cell suspensions depleted of macrophages, the IL-17 production stimulated by ArtinM was reduced by 53% and the exogenous IL-23 acted synergistically with ArtinM in promoting IL-17 production by spleen cell suspensions. We verified that the absence of IL-23, IL-1R, or MyD88 inhibited, but did not block, the IL-17 production by ArtinM-stimulated spleen cells. Therefore, we investigated whether ArtinM exerts a direct effect on CD4⁺ T cells in promoting IL-17 production. Indeed, spleen cell suspensions depleted of CD4⁺ T cells responded to ArtinM with very low levels of IL-17 release. Likewise, isolated CD4⁺ T cells under ArtinM stimulus augmented the expression of TGF-β mRNA and released high levels of IL-17. Considering the observed synergism between IL-23 and ArtinM, we used cells from IL-23 KO mice to assess the direct effect of lectin on CD4⁺ T cells. We verified that ArtinM increased the IL-17 production significantly, a response that was inhibited when the CD4⁺ T cells were pre-incubated with anti-CD3 antibody. In conclusion, ArtinM stimulates the production of IL-17 by CD4⁺ T cells in two major ways: (I) through the induction of IL-23 and IL-1 by APCs and (II) through the direct interaction with CD3 on the CD4⁺ T cells. This study contributes to elucidation of mechanisms accounting for the property of ArtinM in inducing Th17 immunity and opens new perspectives in designing strategies for modulating immunity by using carbohydrate recognition agents.     

Tim-3 ligand galectin-9 reduces IL-17 level and accelerates Klebsiella pneumoniae infection

T cell immunoglobulin and mucin domain (Tim)-3 is expressed on activated CD4⁺ and CD8⁺ T cells. Identification of galectin-9 as a ligand for Tim-3 has now firmly established the Tim-3/galectin-9 pathway, which results in apoptosis of effector CD4⁺ and CD8⁺ T cells. Moreover, Th17 cells are a recently discovered CD4⁺ effector T cell, which are important in antimicrobial immunity. Whether the Tim-3/galectin-9 pathway affects Th17 immunity has not been elucidated. Here, we demonstrated expression of Tim-3 on Th17 cells by flow cytometry. Th17-skewed cells were sensitive to galectin-9-induced apoptosis. In vitro administration of galectin-9 decreased stimulated Th17 cells and inhibited production of IL-17. Interestingly, Klebsiella pneumoniae (K. pneumoniae) infection led to enhanced IL-17 levels. Recombinant galectin-9 significantly decreased IL-17 in vivo, which resulted in reduced bacterial clearance and high mortality. These observations suggest that the Tim-3/galectin-9 pathway plays an important role in termination of Th17-immune responses, and could be a therapeutic target for inflammatory diseases.     

p38α Protein Negatively Regulates T Helper Type 2 Responses by Orchestrating Multiple T Cell Receptor-associated Signals

Mitogen-activated protein kinase p38α is a critical regulator of certain inflammatory diseases. However, its role in T helper type 2 (Th2) responses and allergic inflammation remains unknown. Here we show an increase in the production of interleukin-4 (IL-4) in p38α^−/− CD4⁺ T cells in response to antigen stimulation. p38α-deficient naïve CD4⁺ T cells preferentially differentiate into Th2 cells through increased endogenous production of IL-4. Consistent with those results, we also observed decreased expression of p38α during T helper cell differentiation. Furthermore, deficiency of p38α alters the balance in the expression of NFATc1 and NFATc2 under steady-state conditions and enhances the expression and nuclear translocation of NFATc1 in CD4⁺ T cells upon antigen stimulation. Knockdown of NFATc1 significantly inhibits Th2 differentiation in p38α^−/− T cells but not in p38α^+/− T cells. p38α deficiency also inhibits the activation of Akt but enhances the activation of ERK in response to T cell receptor engagement without impacting IL-2/Stat5 signaling. In a model of ovalbumin-induced acute allergic airway inflammation, mice with induced deletion of p38α show elevated serum ovalbumin-specific IgE level, increased infiltration of eosinophils, and higher concentrations of Th2 cytokines including IL-4 and IL-5 in the bronchoalveolar lavage fluid relative to control mice. Taken together, p38α regulates multiple T cell receptor-associated signals and negatively influences Th2 differentiation and allergic inflammation.     

Plasticity of Migrating CD1b+ and CD1b- Lymph Dendritic Cells in the Promotion of Th1, Th2 and Th17 in Response to Salmonella and Helminth Secretions

Dendritic cells (DCs) are pivotal in the development of specific T-cell responses to control pathogens, as they govern both the initiation and the polarization of adaptive immunity. To investigate the capacities of migrating DCs to respond to pathogens, we used physiologically generated lymph DCs (L-DCs). The flexible polarization of L-DCs was analysed in response to Salmonella or helminth secretions known to induce different T cell responses. Mature conventional CD1b⁺ L-DCs showed a predisposition to promote pro-inflammatory (IL-6), pro-Th1 (IL-12p40) and anti-inflammatory (IL-10) responses which were amplified by Salmonella, and limited to only IL-6 induction by helminth secretions. The other major population of L-DCs did not express the CD1b molecule and displayed phenotypic features of immaturity compared to CD1b⁺ L-DCs. Salmonella infection reduced the constitutive expression of TNF-α and IL-4 mRNA in CD1b^- L-DCs, whereas this expression was not affected by helminth secretions. The cytokine response of T cells promoted by L-DCs was analysed in T cell subsets after co-culture with Salmonella or helminth secretion-driven CD1b⁺ or CD1b^- L-DCs. T cells preferentially expressed the IL-17 gene, and to a lesser extent the IFN-γ and IL-10 genes, in response to Salmonella-driven CD1b⁺ L-DCs, whereas a preferential IL-10, IFN-γ and IL-17 gene expression was observed in response to Salmonella-driven CD1b^- L-DCs. In contrast, a predominant IL-4 and IL-13 gene expression by CD4⁺ and CD8⁺ T cells was observed after stimulation of CD1b⁺ and CD1b^- L-DCs with helminth secretions. These results show that mature conventional CD1b⁺ L-DCs maintain a flexible capacity to respond differently to pathogens, that the predisposition of CD1b^- L-DCs to promote a Th2 response can be oriented towards other Th responses, and finally that the modulation of migrating L-DCs responses is controlled more by the pathogen encountered than the L-DC subsets.     

Antitumor effects and immunoregulation mechanisms of IL-23 gene in mouse mammary cancer mediated by retrovirus

Background: Interleukin (IL)-23, composed of p19 and p40 subunits, has diverse functions in regulating immune systems, enhancing cell-mediated immunity. In the present study, we investigated whether forced expression of the p19-linked p40 gene in murine mammary cancer cells (MA891) produced antitumor effects in vivo. Tumor growth of MA-891 cells expressing IL-23 (IL-23/MA891) in mice was retarded compared with parental and vector DNA-transduced tumors and survival of the mice inoculated with IL-23/MA-891 cells was prolonged. Expressions of the CD4⁺ T cells and CD8⁺ T cells were up-regulated not only in IL-23/MA-891 tumor specimens but also in spleen cells of mice inoculated with IL-23/MA-891 as compared with those of mice inoculated with parental or vector DNA-transduced tumors. Cytotoxic CD8⁺ T lymphocyte (CTL) activity of spleen cells from mice inoculated with IL-23/MA-891 was also significantly higher than the other two groups. Th1-type cytokines such as interferon-γ, TNF-α and IL-12p70 secreted from spleen cells of mice bearing IL-23/MA-891 tumors were increased while Th2-type cytokine IL-4 was negative regulated. Moreover, we have identified that the quantity of DC in spleen cells of mice bearing IL-23/MA-891 tumors was increased as compared with those mice bearing parental or vector DNA-transfected tumors.     

Antitumor vaccination effect of dendritic cells can be augmented by locally utilizing Th1-type cytokines from OK432-reactive CD4+ T cells

 In order to enhance the antitumor vaccination effect of dendritic cells (DC) pulsed with class I tumor peptide, we tried to utilize the local cytokine help of CD4⁺ T cells reactive to a streptococcal preparation OK432. DC were prepared from murine bone marrow cells by culture with both granulocyte/macrophage-colony-stimulating factor and interleukin(IL)-4. The peritumoral injections of OK432 induced OK432-reactive CD4⁺ T cells in the draining lymph nodes, and their in vitro production of interferon γ was thus significantly enhanced by restimulation with OK432-pulsed DC. In addition, anti-P815 mastocytoma cytotoxic T lymphocytes were generated from the in vivo OK432-treated P815-draining lymph node cells only when the lymph node cells were restimulated in vitro with the DC pulsed with both P1A peptide and OK432. Moreover, the peritumoral injections of OK432 and the subsequent vaccination of the DC, pulsed with both OK432 and P1A peptide, significantly suppressed the growth of s.c. inoculated P815. Interestingly, a significant level of IL-12 was detected in the coculture supernatant of both OK432-pulsed DC and OK432-reactive CD4⁺ T cells. Collectively, our results suggest that the antitumor vaccination effect of DC pulsed with class I tumor peptide could thus be effectively augmented by locally utilizing the Th1-type cytokines from OK432-reactive CD4⁺ T cells. Received: 18 July 1997 / Accepted: 23 December 1997     

Mycobacterium paratuberculosis CobT Activates Dendritic Cells via Engagement of Toll-like Receptor 4 Resulting in Th1 Cell Expansion

Mycobacterium avium subsp. paratuberculosis (MAP) is the causative agent of Johne disease in animals and MAP involvement in human Crohn disease has been recently emphasized. Evidence from M. tuberculosis studies suggests mycobacterial proteins activate dendritic cells (DCs) via Toll-like receptor (TLR) 4, eventually determining the fate of immune responses. Here, we investigated whether MAP CobT contributes to the development of T cell immunity through the activation of DCs. MAP CobT recognizes TLR4, and induces DC maturation and activation via the MyD88 and TRIF signaling cascades, which are followed by MAP kinases and NF-κB. We further found that MAP CobT-treated DCs activated naive T cells, effectively polarized CD4⁺ and CD8⁺ T cells to secrete IFN-γ and IL-2, but not IL-4 and IL-10, and induced T cell proliferation. These data indicate that MAP CobT contributes to T helper (Th) 1 polarization of the immune response. MAP CobT-treated DCs specifically induced the expansion of CD4⁺/CD8⁺CD44^highCD62L^low memory T cells in the mesenteric lymph node of MAP-infected mice in a TLR4-dependent manner. Our results indicate that MAP CobT is a novel DC maturation-inducing antigen that drives Th1 polarized-naive/memory T cell expansion in a TLR4-dependent cascade, suggesting that MAP CobT potentially links innate and adaptive immunity against MAP.     

Galectin-9 induces maturation of human monocyte-derived dendritic cells

Maturation of dendritic cells (DCs) is critical for initiation of immune responses and is regulated by various stimulatory signals. We assessed the role of galectin (Gal)-9 in DC maturation. Culture of immature DCs with exogenous Gal-9 markedly increased the surface expression of CD40, CD54, CD80, CD83, CD86, and HLA-DR in a dose-dependent manner, although Gal-9 had no or little effect on differentiation of human monocytes into immature DCs. Gal-9-treated DCs secreted IL-12 but not IL-10, and they elicited the production of Th1 cytokines (IFN-gamma and IL-2) but not that of the Th2 cytokines (IL-4 and IL-5) by allogeneic CD4+ T cells. These effects of Gal-9 on immature DCs were not essentially dependent on its lectin properties, given that they were inhibited only slightly by lactose. We further found that a Gal-9 mutant that lacks beta-galactoside binding activity reproduced the above activities and that an anti-Gal-9 mAb suppressed them. Gal-9 induced phosphorylation of the MAPK p38 and ERK1/2 in DCs, and an inhibitor of p38 signaling, but not inhibitors of signaling by either ERK1/2 or PI3K, blocked Gal-9-induced up-regulation of costimulatory molecule expression and IL-12 production. These findings suggest that Gal-9 plays a role not only in innate immunity but also in acquired immunity by inducing DC maturation and promoting Th1 immune responses.     

Increased intratumoral IL-22-producing CD4+ T cells and Th22 cells correlate with gastric cancer progression and predict poor patient survival

IL-22-producing CD4⁺ T cells (IL-22⁺CD4⁺ T cells) and Th22 cells (IL-22⁺IL-17^?IFN-γ^?CD4⁺ T cells) represent newly discovered T-cell subsets, but their nature, regulation, and clinical relevance in gastric cancer (GC) are presently unknown. In our study, the frequency of IL-22⁺CD4⁺ T cells in tumor tissues from 76 GC patients was significantly higher than that in tumor-draining lymph nodes, non-tumor, and peritumoral tissues. Most intratumoral IL-22⁺CD4⁺ T cells co-expressed IL-17 and IFN-γ and showed a memory phenotype. Locally enriched IL-22⁺CD4⁺ T cells positively correlated with increased CD14⁺ monocytes and IL-6 and IL-23 detection ex vivo, and in vitro IL-6 and IL-23 induced the polarization of IL-22⁺CD4⁺ T cells in a dose-dependent manner and the polarized IL-22⁺CD4⁺ T cells co-expressed of IL-17 and IFN-γ. Moreover, IL-22⁺CD4⁺ T-cell subsets (IL-22⁺IL-17⁺CD4⁺, IL-22⁺IL-17^?CD4⁺, IL-22⁺IFN-γ⁺CD4⁺, IL-22⁺IFN-γ^?CD4⁺, and IL-22⁺IL-17⁺IFN-γ⁺CD4⁺ T cells), and Th22 cells were also increased in tumors. Furthermore, higher intratumoral IL-22⁺CD4⁺ T-cell percentage and Th22-cell percentage were found in patients with tumor-node-metastasis stage advanced and predicted reduced overall survival. In conclusion, our data indicate that IL-22⁺CD4⁺ T cells and Th22 cells are likely important in establishing the tumor microenvironment for GC; increased intratumoral IL-22⁺CD4⁺ T cells and Th22 cells are associated with tumor progression and predict poorer patient survival, suggesting that tumor-infiltrating IL-22⁺CD4⁺ T cells and Th22 cells may be suitable therapeutic targets in patients with GC.     

A B-cell lymphoma vaccine using a depot formulation of interleukin-2 induces potent antitumor immunity despite increased numbers of intratumoral regulatory T cells

Therapeutic vaccination holds great potential as complementary treatment for non-Hodgkin’s lymphoma. Here, we report that a therapeutic whole cell vaccine formulated with IL-2 adsorbed onto aluminum hydroxide as cytokine-depot formulation elicits potent antitumor immunity and induces delayed tumor growth, control of tumor dissemination and longer survival in mice challenged with A20-lymphoma. Therapeutic vaccination induced higher numbers of tumor’s infiltrating lymphocytes (CD4⁺ and CD8⁺ T cells and NK cells), and the production of IFN-γ and IL-4 by intratumoral CD4⁺ T cells. Further, strong tumor antigen-specific cellular responses were detected at systemic level. Both the A20-derived antigenic material and the IL-2 depot formulation were required for induction of an effective immune response that impacted on cancer progression. All mice receiving any form of IL-2, either as part of the vaccine or alone as control, showed higher numbers of CD4⁺CD25^+/highFoxp3⁺ regulatory T cells (Treg) in the tumor, which might have a role in tumor progression in these animals. Nevertheless, for those animals that received the cytokine as part of the vaccine formulation, the overall effect was improved immune response and less disseminated disease, suggesting that therapeutic vaccination overcomes the potential detrimental effect of intratumoral Treg cells. Overall, the results presented here show that a simple vaccine formulation, that can be easily prepared under GMP conditions, is a promising strategy to be used in B-cell lymphoma and may have enough merit to be tested in clinical trials.     

CD103+CD11b+ Dendritic Cells Induce Th17 T Cells in Muc2-Deficient Mice with Extensively Spread Colitis

Mucus alterations are a feature of ulcerative colitis (UC) and can drive inflammation by compromising the mucosal barrier to luminal bacteria. The exact pathogenesis of UC remains unclear, but CD4⁺ T cells reacting to commensal antigens appear to contribute to pathology. Given the unique capacity of dendritic cells (DCs) to activate naive T cells, colon DCs may activate pathogenic T cells and contribute to disease. Using Muc2^-/- mice, which lack a functional mucus barrier and develop spontaneous colitis, we show that colitic animals have reduced colon CD103⁺CD11b^- DCs and increased CD103^-CD11b⁺ phagocytes. Moreover, changes in colonic DC subsets and distinct cytokine patterns distinguish mice with distally localized colitis from mice with colitis spread proximally. Specifically, mice with proximally spread, but not distally contained, colitis have increased IL-1β, IL-6, IL-17, TNFα, and IFNγ combined with decreased IL-10 in the distal colon. These individuals also have increased numbers of CD103⁺CD11b⁺ DCs in the distal colon. CD103⁺CD11b⁺ DCs isolated from colitic but not noncolitic mice induced robust differentiation of Th17 cells but not Th1 cells ex vivo. In contrast, CD103^-CD11b⁺ DCs from colitic Muc2^-/- mice induced Th17 as well as Th1 differentiation. Thus, the local environment influences the capacity of intestinal DC subsets to induce T cell proliferation and differentiation, with CD103⁺CD11b⁺ DCs inducing IL-17-producing T cells being a key feature of extensively spread colitis.