Feedback regulatory circuits provided by regulatory T cells (Treg cells) and suppressive cytokines are an intrinsic part of the immune system, along with effector functions. Here we discuss some of the regulatory cytokines that have evolved to permit tolerance to components of self as well as the eradication of pathogens with minimal collateral damage to the host. Interleukin 2 (IL-2), IL-10 and transforming growth factor-β (TGF-β) are well characterized, whereas IL-27, IL-35 and IL-37 represent newcomers to the spectrum of anti-inflammatory cytokines. We also emphasize how information accumulated through in vitro as well as in vivo studies of genetically engineered mice can help in the understanding and treatment of human diseases.
Broadly neutralizing antibodies directed against the conserved stalk domain of the viral hemagglutinin have attracted increasing attention in recent years. However, only a limited number of stalk antibodies directed against group 2 influenza hemagglutinins have been isolated so far. Also, little is known about the general level of induction of these antibodies by influenza virus vaccination or infection. To characterize the anti-stalk humoral response in the mouse model as well as in humans, chimeric hemagglutinin constructs previously developed in our group were employed in serological assays. Whereas influenza virus infection induced high titers of stalk-reactive antibodies, immunization with inactivated influenza virus vaccines failed to do so in the mouse model. Analysis of serum samples collected from human individuals who were infected by influenza viruses also revealed the induction of stalk-reactive antibodies. Finally, we show that the hemagglutinin stalk-directed antibodies induced in mice and humans have broad reactivity and neutralizing activity in vitro and in vivo. The results of the study point toward the existence of highly conserved epitopes in the stalk domains of group 2 hemagglutinins, which can be targeted for the development of a universal influenza virus vaccine in humans.
About half of all subjects with common variable immune deficiency (CVID) are afflicted with inflammatory complications including hematologic autoimmunity, granulomatous infiltrations, interstitial lung disease, lymphoid hyperplasia and/or gastrointestinal inflammatory disease. The pathogenesis of these conditions is poorly understood but singly and in aggregate, these lead to significantly increased (11 fold) morbidity and mortality, not experienced by CVID subjects without these complications. To explore the dysregulated networks in these subjects, we applied whole blood transcriptional profiling to 91 CVID subjects, 47 with inflammatory conditions and 44 without, in comparison to subjects with XLA and healthy controls. As compared to other CVID subjects, males with XLA or healthy controls, the signature of CVID subjects with inflammatory complications was distinguished by a marked up-regulation of IFN responsive genes. Chronic up-regulation of IFN pathways is known to occur in autoimmune disease due to activation of TLRs and other still unclarified cytoplasmic sensors. As subjects with inflammatory complications were also more likely to be lymphopenic, have reduced B cell numbers, and a greater reduction of B, T and plasma cell networks, we suggest that more impaired adaptive immunity in these subjects may lead to chronic activation of innate IFN pathways in response to environmental antigens. The unbiased use of whole blood transcriptome analysis may provides a tool for distinguishing CVID subjects who are at risk for increased morbidity and earlier mortality. As more effective therapeutic options are developed, whole blood transcriptome analyses could also provide an efficient means of monitoring the effects of treatment of the inflammatory phenotype.
Targeting antigens directly to DCs through anti-DC receptor antibody fused to antigen proteins is a promising approach to vaccine development. However, not all antigens can be expressed as a recombinant antibody directly fused to a protein antigen. Here, we show that non-covalent assembly of antibody - antigen complexes, mediated by interaction between dockerin and cohesin domains from cellulose-degrading bacteria, can greatly expand the range of antigens for this DC-targeting vaccine technology. Recombinant antibodies with a dockerin domain fused to the antibody heavy chain C-terminus are efficiently secreted by mammalian cells, while many antigens not secreted as antibody fusion proteins are readily expressed as cohesin directly fused to antigen either via secretion from mammalian cells, or as soluble cytoplasmic E. coli products. These form very stable and homogeneous complexes with antibody fused to dockerin. In vitro, these complexes can efficiently bind to human DC receptors followed by presentation to antigen-specific CD4+ and CD8+ T cells. Low doses of the HA1 subunit of Influenza hemagglutinin conjugated through this means to anti-Langerin antibodies elicited Flu HA1-specific antibody and T cell responses in mice. Thus, the non-covalent assembly of antibody and antigen through dockerin and cohesin interaction provides a useful modular strategy for developing and testing prototype vaccines for eliciting antigen-specific T and B cell responses, particularly when direct antibody fusions to antigen cannot be expressed.
Previous studies have analyzed the lymphoid and myeloid foci within the gingival mucosa in health and chronic periodontitis (CP); however, the principal APCs responsible for the formation and organizational structure of these foci in CP have not been defined. We show that in human CP tissues, CD1a+ immature Langerhans cells predominantly infiltrate the gingival epithelium, whereas CD83+ mature dendritic cells (DCs) specifically infiltrate the CD4+ lymphoid-rich lamina propria. In vivo evidence shows that exacerbation of CP results in increased levels of proinflammatory cytokines that mediate DC activation/maturation, but also of counterregulatory cytokines that may prevent a Th-polarized response. Consistently, in vitro-generated monocyte-derived DCs pulsed with Porphyromonas gingivalis strain 381 or its LPS undergo maturation, up-regulate accessory molecules, and release proinflammatory (IL-1β, PGE2) and Th (IL-10, IL-12) cytokines. Interestingly, the IL-10:IL-12 ratio elicited from P. gingivalis-pulsed DCs was 3-fold higher than that from Escherichia coli-pulsed DCs. This may account for the significantly (p < 0.05) lower proliferation of autologous CD4+ T cells and reduced release of IFN-γ elicited by P. gingivalis-pulsed DCs. Taken together, these findings suggest a previously unreported mechanism for the pathophysiology of CP, involving the activation and in situ maturation of DCs by the oral pathogen P. gingivalis, leading to release of counterregulatory cytokines and the formation of T cell-DC foci.
The adaptive immune system has evolved distinct responses against different pathogens, but the mechanism(s) by which a particular response is initiated is poorly understood. In this study, we investigated the type of Ag-specific CD4+ Th and CD8+ T cell responses elicited in vivo, in response to soluble OVA, coinjected with LPS from two different pathogens. We used Escherichia coli LPS, which signals through Toll-like receptor 4 (TLR4) and LPS from the oral pathogen Porphyromonas gingivalis, which does not appear to require TLR4 for signaling. Coinjections of E. coli LPS + OVA or P. gingivalis LPS + OVA induced similar clonal expansions of OVA-specific CD4+ and CD8+ T cells, but strikingly different cytokine profiles. E. coli LPS induced a Th1-like response with abundant IFN-γ, but little or no IL-4, IL-13, and IL-5. In contrast, P. gingivalis LPS induced Th and T cell responses characterized by significant levels of IL-13, IL-5, and IL-10, but lower levels of IFN-γ. Consistent with these results, E. coli LPS induced IL-12(p70) in the CD8α+ dendritic cell (DC) subset, while P. gingivalis LPS did not. Both LPS, however, activated the two DC subsets to up-regulate costimulatory molecules and produce IL-6 and TNF-α. Interestingly, these LPS appeared to have differences in their ability to signal through TLR4; proliferation of splenocytes and cytokine secretion by splenocytes or DCs from TLR4-deficient C3H/HeJ mice were greatly impaired in response to E. coli LPS, but not P. gingivalis LPS. Therefore, LPS from different bacteria activate DC subsets to produce different cytokines, and induce distinct types of adaptive immunity in vivo.
New approaches to define factors underlying the immunopathogenesis of pulmonary diseases including sarcoidosis and tuberculosis are needed to develop new treatments and biomarkers. Comparing the blood transcriptional response of tuberculosis to other similar pulmonary diseases will advance knowledge of disease pathways and help distinguish diseases with similar clinical presentations.
To determine the factors underlying the immunopathogenesis of the granulomatous diseases, sarcoidosis and tuberculosis, by comparing the blood transcriptional responses in these and other pulmonary diseases.
We compared whole blood genome-wide transcriptional profiles in pulmonary sarcoidosis, pulmonary tuberculosis, to community acquired pneumonia and primary lung cancer and healthy controls, before and after treatment, and in purified leucocyte populations.
Measurements and Main Results
An Interferon-inducible neutrophil-driven blood transcriptional signature was present in both sarcoidosis and tuberculosis, with a higher abundance and expression in tuberculosis. Heterogeneity of the sarcoidosis signature correlated significantly with disease activity. Transcriptional profiles in pneumonia and lung cancer revealed an over-abundance of inflammatory transcripts. After successful treatment the transcriptional activity in tuberculosis and pneumonia patients was significantly reduced. However the glucocorticoid-responsive sarcoidosis patients showed a significant increase in transcriptional activity. 144-blood transcripts were able to distinguish tuberculosis from other lung diseases and controls.
Tuberculosis and sarcoidosis revealed similar blood transcriptional profiles, dominated by interferon-inducible transcripts, while pneumonia and lung cancer showed distinct signatures, dominated by inflammatory genes. There were also significant differences between tuberculosis and sarcoidosis in the degree of their transcriptional activity, the heterogeneity of their profiles and their transcriptional response to treatment.
The pivotal role of DCs in initiating the immune responses led to their use as vaccine vectors. However, the relationship between DC subsets involved in antigen presentation and the type of elicited immune responses underlined the need for the characterization of the DCs generated in vitro. The phenotypes of tissue-derived APCs from a cynomolgus macaque model for human vaccine development were compared with ex vivo-derived DCs. Monocyte/macrophages predominated in bone marrow (BM) and blood. Myeloid DCs (mDCs) were present in all tested tissues and were more highly represented than plasmacytoid DCs (pDCs). As in human skin, Langerhans cells (LCs) resided exclusively in the macaque epidermis, expressing CD11c, high levels of CD1a and Langerin (CD207). Most DC subsets were endowed with tissue-specific combinations of PRRs. DCs generated from CD34+ BM cells (CD34-DCs) were heterogeneous in phenotype. CD34-DCs shared properties (differentiation and PRR) of dermal and epidermal DCs. After injection into macaques, CD34-DCs expressing HIV-Gag induced Gag-specific CD4+ and CD8+ T cells producing IFN-γ, TNF-α, MIP-1β or IL-2. In high responding animals, the numbers of polyfunctional CD8+ T cells increased with the number of booster injections. This DC-based vaccine strategy elicited immune responses relevant to the DC subsets generated in vitro.
Dendritic cells; Vaccination; Immune responses; Antigen presenting cells
Type I interferon is a family of antiviral cytokines linked to human autoimmune diseases. In this issue of Immunity, Gall et al. (2012) characterize, in a murine model of autoimmunity, the origin and progression of the type I interferon response leading to disease.
Cancer immunotherapy attempts to harness the power and specificity of the immune system to treat tumours. The molecular identification of human cancer-specific antigens has allowed the development of antigen-specific immunotherapy. In one approach, autologous antigen-specific T cells are expanded ex vivo and then re-infused into patients. Another approach is through vaccination; that is, the provision of an antigen together with an adjuvant to elicit therapeutic T cells in vivo. Owing to their properties, dendritic cells (DCs) are often called ‘nature’s adjuvants’ and thus have become the natural agents for antigen delivery. After four decades of research, it is now clear that DCs are at the centre of the immune system owing to their ability to control both immune tolerance and immunity. Thus, DCs are an essential target in efforts to generate therapeutic immunity against cancer.
Macrophage production of CXCL10 amplifies the production of IL-6 by B cells, leading to plasma cell differentiation.
In tonsils, CD138+ plasma cells (PCs) are surrounded by CD163+ resident macrophages (Mϕs). We show here that human Mϕs (isolated from tonsils or generated from monocytes in vitro) drive activated B cells to differentiate into CD138+CD38++ PCs through secreted CXCL10/IP-10 and VCAM-1 contact. IP-10 production by Mϕs is induced by B cell–derived IL-6 and depends on STAT3 phosphorylation. Furthermore, IP-10 amplifies the production of IL-6 by B cells, which sustains the STAT3 signals that lead to PC differentiation. IP-10–deficient mice challenged with NP-Ficoll show a decreased frequency of NP-specific PCs and lower titers of antibodies. Thus, our results reveal a novel dialog between Mϕs and B cells, in which IP-10 acts as a PC differentiation factor.
Determination of antigen-specific T cell repertoires in human blood has been a challenge. Here, we show a novel integrated approach that permits determination of multiple parameters of antigen-specific T cell repertoires. The approach consists of two assays: the Direct assay and the Cytokine-driven assay. Briefly, human PBMCs are first stimulated with overlapping peptides encoding a given antigen for 48 hours to measure cytokine secretion (Direct assay). Peptide-reactive T cells are further expanded by IL-2 for 5 days; and after overnight starvation, expanded cells are stimulated with the same peptides from the initial culture to analyze cytokine secretion (Cytokine-driven assay). We first applied this integrated approach to determine the type of islet-antigen-specific T cells in healthy adults. Out of ten donors, the Direct assay identified GAD65-specific CD4+ T cells in three adults and zinc transporter 8 (ZnT8)-specific CD4+ T cells in five adults. The intracytoplasmic cytokine staining assay showed that these islet-antigen-specific CD4+ T cells belonged to the CD45RO+ memory compartment. The Cytokine-driven assay further revealed that islet-antigen-specific CD4+ T cells in healthy adults were capable of secreting various types of cytokines including type 1 and type 2 cytokines as well as IL-10. We next applied our integrated assay to determine whether the type of ZnT8-specific CD4+ T cells is different between Type 1 diabetes patients and age/gender/HLA-matched healthy adults. We found that ZnT8-specific CD4+ T cells were skewed towards Th1 cells in T1D patients, while Th2 and IL-10-producing cells were prevalent in healthy adults. In conclusion, the Direct assay and the Cytokine-driven assay complement each other, and the combination of the two assays provides information of antigen-specific T cell repertoires on the breadth, type, and avidity. This strategy is applicable to determine the differences in the quality of antigen-specific T cells between health and disease.
Monocytes exposed to serum from SLE patients promote B cell differentiation to IgG and IgA plasmablasts dependent on BAFF and IL-10 or APRIL, respectively.
The development of autoantibodies is a hallmark of systemic lupus erythematosus (SLE). SLE serum can induce monocyte differentiation into dendritic cells (DCs) in a type I IFN–dependent manner. Such SLE-DCs activate T cells, but whether they promote B cell responses is not known. In this study, we demonstrate that SLE-DCs can efficiently stimulate naive and memory B cells to differentiate into IgG- and IgA-plasmablasts (PBs) resembling those found in the blood of SLE patients. SLE-DC–mediated IgG-PB differentiation is dependent on B cell–activating factor (BAFF) and IL-10, whereas IgA-PB differentiation is dependent on a proliferation-inducing ligand (APRIL). Importantly, SLE-DCs express CD138 and trans-present CD138-bound APRIL to B cells, leading to the induction of IgA switching and PB differentiation in an IFN-α–independent manner. We further found that this mechanism of providing B cell help is relevant in vivo, as CD138-bound APRIL is expressed on blood monocytes from active SLE patients. Collectively, our study suggests that a direct myeloid DC–B cell interplay might contribute to the pathogenesis of SLE.
Bacterial cyclic glucans are glucose polymers that concentrate within the periplasm of alpha-proteobacteria. These molecules are necessary to maintain the homeostasis of the cell envelope by contributing to the osmolarity of Gram negative bacteria. Here, we demonstrate that Brucella β 1,2 cyclic glucans are potent activators of human and mouse dendritic cells. Dendritic cells activation by Brucella β 1,2 cyclic glucans requires TLR4, MyD88 and TRIF, but not CD14. The Brucella cyclic glucans showed neither toxicity nor immunogenicity compared to LPS and triggered antigen-specific CD8+ T cell responses in vivo. These cyclic glucans also enhanced antigen-specific CD4+ and CD8+ T cell responses including cross-presentation by different human DC subsets. Brucella β 1,2 cyclic glucans increased the memory CD4+ T cell responses of blood mononuclear cells exposed to recombinant fusion proteins composed of anti-CD40 antibody and antigens from both hepatitis C virus and Mycobacterium tuberculosis. Thus cyclic glucans represent a new class of adjuvants, which might contribute to the development of effective antimicrobial therapies.
Vaccination is one of the key strategies to fight against infectious diseases though numerous diseases remain without appropriate vaccines. The challenge is to generate potent vaccines capable of inducing long-lasting immunity in humans. Successful vaccines include adjuvants that enhance and appropriately skew the immune response to given antigens. The development of new adjuvants for human vaccines has become an expanding field of research. Here we show that bacterial cyclic β-glucans can be used to enhance cellular immunity by activation of dendritic cells, from both mice and humans. In particular, Cyclic-β glucans enhance the in vitro memory CD4+ T cell responses of patients suffering from hepatitis C and tuberculosis. Thus cyclic-β glucans are new adjuvants, which might be used in vaccines.
Tuberculosis (TB), caused by infection with Mycobacterium tuberculosis (M. tuberculosis), is a major cause of morbidity and mortality worldwide and efforts to control TB are hampered by difficulties with diagnosis, prevention and treatment 1,2. Most people infected with M. tuberculosis remain asymptomatic, termed latent TB, with a 10% lifetime risk of developing active TB disease, but current tests cannot identify which individuals will develop disease 3. The immune response to M. tuberculosis is complex and incompletely characterized, hindering development of new diagnostics, therapies and vaccines 4,5. We identified a whole blood 393 transcript signature for active TB in intermediate and high burden settings, correlating with radiological extent of disease and reverting to that of healthy controls following treatment. A subset of latent TB patients had signatures similar to those in active TB patients. We also identified a specific 86-transcript signature that discriminated active TB from other inflammatory and infectious diseases. Modular and pathway analysis revealed that the TB signature was dominated by a neutrophil-driven interferon (IFN)-inducible gene profile, consisting of both IFN-γ and Type I IFNαβ signalling. Comparison with transcriptional signatures in purified cells and flow cytometric analysis, suggest that this TB signature reflects both changes in cellular composition and altered gene expression. Although an IFN signature was also observed in whole blood of patients with Systemic Lupus Erythematosus (SLE), their complete modular signature differed from TB with increased abundance of plasma cell transcripts. Our studies demonstrate a hitherto under-appreciated role of Type I IFNαβ signalling in TB pathogenesis, which has implications for vaccine and therapeutic development. Our study also provides a broad range of transcriptional biomarkers with potential as diagnostic and prognostic tools to combat the TB epidemic.
Globally there are approximately 9 million new active tuberculosis cases and 1.4 million deaths annually. Effective antituberculosis treatment monitoring is difficult as there are no existing biomarkers of poor adherence or inadequate treatment earlier than 2 months after treatment initiation. Inadequate treatment leads to worsening disease, disease transmission and drug resistance.
To determine if blood transcriptional signatures change in response to antituberculosis treatment and could act as early biomarkers of a successful response.
Blood transcriptional profiles of untreated active tuberculosis patients in South Africa were analysed before, during (2 weeks and 2 months), at the end of (6 months) and after (12 months) antituberculosis treatment, and compared to individuals with latent tuberculosis. An active-tuberculosis transcriptional signature and a specific treatment-response transcriptional signature were derived. The specific treatment response transcriptional signature was tested in two independent cohorts. Two quantitative scoring algorithms were applied to measure the changes in the transcriptional response. The most significantly represented pathways were determined using Ingenuity Pathway Analysis.
An active tuberculosis 664-transcript signature and a treatment specific 320-transcript signature significantly diminished after 2 weeks of treatment in all cohorts, and continued to diminish until 6 months. The transcriptional response to treatment could be individually measured in each patient.
Significant changes in the transcriptional signatures measured by blood tests were readily detectable just 2 weeks after treatment initiation. These findings suggest that blood transcriptional signatures could be used as early surrogate biomarkers of successful treatment response.
Targeting antigens to the lectinlike DC-ASGPR receptor on human DCs and in nonhuman primates results in the induction of antigen-specific IL-10–producing CD4+ T cells.
Dendritic cells (DCs) can initiate and shape host immune responses toward either immunity or tolerance by their effects on antigen-specific CD4+ T cells. DC-asialoglycoprotein receptor (DC-ASGPR), a lectinlike receptor, is a known scavenger receptor. Here, we report that targeting antigens to human DCs via DC-ASGPR, but not lectin-like oxidized-LDL receptor, Dectin-1, or DC-specific ICAM-3–grabbing nonintegrin favors the generation of antigen-specific suppressive CD4+ T cells that produce interleukin 10 (IL-10). These findings apply to both self- and foreign antigens, as well as memory and naive CD4+ T cells. The generation of such IL-10–producing CD4+ T cells requires p38/extracellular signal-regulated kinase phosphorylation and IL-10 induction in DCs. We further demonstrate that immunization of nonhuman primates with antigens fused to anti–DC-ASGPR monoclonal antibody generates antigen-specific CD4+ T cells that produce IL-10 in vivo. This study provides a new strategy for the establishment of antigen-specific IL-10–producing suppressive T cells in vivo by targeting whole protein antigens to DCs via DC-ASGPR.
As detailed in the Appreciation piece written by Carol Moberg, Ralph’s
discovery and investigation of DCs constituted an enormous contribution to
immunology. However, Ralph’s influence extended far beyond the strictly
scientific. Below, some of Ralph’s closest colleagues and friends reflect
on the long-lasting effects of his unwavering mentorship, enthusiasm,
generosity, and friendship.
Also in this issue is a Perspective, originally commissioned by Ralph and written
by Robin Weiss
and Peter Vogt. Ralph passed away before he could read
this engaging piece, which celebrates the centennial of the publication in the
JEM of the Nobel Prize-winning work of Peyton Rous. In
addition to their Nobel Prizes, Ralph and Peyton Rous shared the distinctions of
being long-time leaders of Rockefeller laboratories and editors of this
Staphylococcus aureus infections are associated with diverse clinical manifestations leading to significant morbidity and mortality. To define the role of the host response in the clinical manifestations of the disease, we characterized whole blood transcriptional profiles of children hospitalized with community-acquired S. aureus infection and phenotyped the bacterial strains isolated. The overall transcriptional response to S. aureus infection was characterized by over-expression of innate immunity and hematopoiesis related genes and under-expression of genes related to adaptive immunity. We assessed individual profiles using modular fingerprints combined with the molecular distance to health (MDTH), a numerical score of transcriptional perturbation as compared to healthy controls. We observed significant heterogeneity in the host signatures and MDTH, as they were influenced by the type of clinical presentation, the extent of bacterial dissemination, and time of blood sampling in the course of the infection, but not by the bacterial isolate. System analysis approaches provide a new understanding of disease pathogenesis and the relation/interaction between host response and clinical disease manifestations.
Systemic lupus erythematosus (SLE) is a systemic autoimmune disease characterized by a breakdown of tolerance to nuclear antigens and the development of immune complexes. Genomic approaches have shown that human SLE leukocytes homogeneously express type I interferon (IFN)–induced and neutrophil-related transcripts. Increased production and/or bioavailability of IFN-α and associated alterations in dendritic cell (DC) homeostasis have been linked to lupus pathogenesis. Although neutrophils have long been shown to be associated with lupus, their potential role in disease pathogenesis remains elusive. Here, we show that mature SLE neutrophils are primed in vivo by type I IFN and die upon exposure to SLE-derived anti-ribonucleoprotein antibodies, releasing neutrophil extracellular traps (NETs). SLE NETs contain DNA as well as large amounts of LL37 and HMGB1, neutrophil proteins that facilitate the uptake and recognition of mammalian DNA by plasmacytoid DCs (pDCs). Indeed, SLE NETs activate pDCs to produce high levels of IFN-α in a DNA- and TLR9 (Toll-like receptor 9)–dependent manner. Our results reveal an unsuspected role for neutrophils in SLE pathogenesis and identify a novel link between nucleic acid–recognizing antibodies and type I IFN production in this disease.
IFNα is known to play a critical role in the pathogenesis of systemic lupus erythematosus (SLE), but the mechanisms remain unclear. We previously showed that within weeks, exposure to IFNα in vivo induces lupus in pre-autoimmune lupus-prone NZB × NZW F1 (NZB/W) but not in BALB/c mice. In the current study, we show that in vivo expression of IFNα induces sustained B cell proliferation in both BALB/c and NZB/W mice. In NZB/W but not BALB/c mice, B cell proliferation was accompanied by a rapid and unabated production of autoantibody-secreting cells (ASCs) in secondary lymphoid organs, suggesting that a B cell checkpoint is altered in the autoimmune background. The majority (>95%) of ASCs elicited in IFNα-treated NZB/W mice were short-lived and occurred without the induction of long-lived plasma cells. A short course of cyclophosphamide caused a sharp drop in IFNα-elicited short-lived plasma cells, but the levels recovered within days following termination of treatment. Thus, our work provides new insights into effectiveness and limitations of current SLE therapies.
lupus; interferon alpha; B lymphocytes; short-lived plasma cells; cyclophosphamide
In order to develop improved vaccines for patients with recurrent prostate cancer (PCa), we tested the feasibility of using type-1-polarized dendritic cells (DC1s) to cross-present antigens from allogeneic PCa cells and to induce functional CD8+ T cell responses against PCa cells and against defined MHC class I-restricted PCa-relevant epitopes.
Monocyte-derived DCs from PCa patients were matured using the “standard” cytokine cocktail (IL-1β/TNFα/IL-6/PGE2) or using the αDC1-polarizing cocktail (IL-1β/TNFα/IFNα/IFNγ/poly-I:C), loaded with UV-irradiated LNCaP cells, and used to sensitize autologous CD8+ T cells.
αDC1s from PCa patients secreted 10-30 times higher levels of IL-12p70 than sDCs. Importantly this elevated capacity for IL-12p70 secretion was not inhibited by loading with apoptotic tumor cells. Comparing to standard DCs, αDC1s induced higher numbers of CD8+ T cells capable of recognizing both the original PCa cells as well as another PCa cell line, DU145, in MHC class I-restricted fashion. Furthermore, αDC1s induced higher numbers of CD8+ T cells recognizing defined prostate cancer-specific class I-restricted peptide epitopes of prostate-specific antigen and prostatic acid phosphatase: PAP135-143(average 49-fold higher), PAP112-120 (average 24-fold), PSA141-150 (average 5.5-fold) and PSA146-154 (average 11-fold).
Type-1 polarization of GM-CSF/IL-4-generated DCs enhances their ability to present allogeneic tumor cells and to induce CD8+ T cells recognizing different prostate cancer cells and multiple defined prostate cancer-specific epitopes. These observations help to develop improved immunotherapies of prostate cancer for patients with different HLA types and lacking autologous tumor material.
prostate cancer; vaccines; dendritic cells; IL-12; CTLs
The adoptive transfer of cancer antigen-specific effector T cells in patients can result in tumor rejection, thereby illustrating the immune system potential for cancer therapy. Ideally, one would like to directly induce efficient tumor-specific effector and memory T cells through vaccination. Therapeutic vaccines have two objectives: priming antigen-specific T cells and reprogramming memory T cells, i.e., a transformation from one type of immunity to another (e.g., regulatory to cytotoxic). Recent successful phase III clinical trials showing benefit to the patients revived cancer vaccines. Dendritic cells (DCs) are essential in generation of immune responses and as such represent targets and vectors for vaccination. We have learned that different DC subsets elicit different T cells. Similarly, different activation methods result in DCs able to elicit distinct T cells. We contend that a careful manipulation of activated DCs will allow cancer immunotherapists to produce the next generation of highly efficient cancer vaccines.
dendritic cells; cancer; vaccines; T cells
Dendritic cells (DCs) were discovered in 1973 by Ralph Steinman as a previously undefined cell type in the mouse spleen and are now recognized as a group of related cell populations that induce and regulate adaptive immune responses. Studies of the past decade show that, both in mice and humans, DCs are composed of subsets that differ in their localization, phenotype, and functions. These progresses in our understanding of DC biology provide a new framework for improving human health. In this review, we discuss human DC subsets in the context of their medical applications, with a particular focus on DC targeting.
Although a fraction of human blood memory CD4+ T cells expresses chemokine (C-X-C motif) receptor 5 (CXCR5), their relationship to T follicular helper (Tfh) cells is not well-established. Here we show that human blood CXCR5+ CD4+ T cells share functional properties with Tfh cells, and appear to represent their circulating memory compartment. Blood CXCR5+ CD4+ T cells comprised three subsets; T helper 1 (Th1), Th2 and Th17 cells. Th2 and Th17 cells within CXCR5+, but not within CXCR5−, compartment efficiently induced naïve B cells to produce immunoglobulins via interleukin-21 (IL-21). In contrast, Th1 cells from both CXCR5+ and CXCR5− compartments lacked the capacity to help B cells. Patients with juvenile dermatomyositis, a systemic autoimmune disease, displayed a profound skewing of blood CXCR5+ Th subsets towards Th2 and Th17 cells. Importantly, the skewing of subsets correlated with disease activity and frequency of blood plasmablasts. Collectively, our study suggests that an altered balance of Tfh subsets contributes to human autoimmunity.