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1.  Transcriptional specialization of human dendritic cell subsets in response to microbial vaccines 
Nature Communications  2014;5:5283.
The mechanisms by which microbial vaccines interact with human APCs remain elusive. Herein, we describe the transcriptional programs induced in human DCs by pathogens, innate receptor ligands and vaccines. Exposure of DCs to influenza, Salmonella enterica and Staphylococcus aureus allows us to build a modular framework containing 204 transcript clusters. We use this framework to characterize the responses of human monocytes, monocyte-derived DCs and blood DC subsets to 13 vaccines. Different vaccines induce distinct transcriptional programs based on pathogen type, adjuvant formulation and APC targeted. Fluzone, Pneumovax and Gardasil, respectively, activate monocyte-derived DCs, monocytes and CD1c+ blood DCs, highlighting APC specialization in response to vaccines. Finally, the blood signatures from individuals vaccinated with Fluzone or infected with influenza reveal a signature of adaptive immunity activation following vaccination and symptomatic infections, but not asymptomatic infections. These data, offered with a web interface, may guide the development of improved vaccines.
The effects of vaccines on human dendritic cells (DCs) are incompletely understood. Here the authors build a transcriptional modular network based on in vitro infection of human DCs and apply it for the characterization of the DC response to 13 different vaccines.
PMCID: PMC4206838  PMID: 25335753
2.  Targeting concatenated HIV antigens to human CD40 expands a broad repertoire of multifunctional CD4+ and CD8+ T cells 
AIDS (London, England)  2013;27(13):10.1097/QAD.0b013e3283624305.
Targeting HIV antigens directly to dendritic cells using monoclonal antibodies against cell-surface receptors has been shown to evoke potent cellular immunity in animal models. The objective of this study was to configure an anti-human CD40 antibody fused to a string of five highly conserved CD4+ and CD8+ T-cell epitope-rich regions of HIV-1 Gag, Nef and Pol (αCD40.HIV5pep), and then to demonstrate the capacity of this candidate therapeutic vaccine to target these HIV peptide antigens to human dendritic cells to expand functional HIV-specific T cells.
Antigen-specific cytokine production using intracellular flow cytometry and multiplex bead-based assay, and suppression of viral inhibition, were used to characterize the T cells expanded by αCD40.HIV5pep from HIV-infected patient peripheral blood mononuclear cell (PBMC) and dendritic cell/T-cell co-cultures.
This candidate vaccine expands memory CD4+ and CD8+ T cells specific to multiple epitopes within all five peptide regions across a wide range of major histocompatibility complex (MHC) haplotypes from HIV-infected patient PBMC and dendritic cell/T-cell co-cultures. These in vitro expanded HIV antigen-specific CD4+ and CD8+ T cells produce multiple cytokines and chemokines. αCD40.HIV5pep-expanded CD8+ T cells have characteristics of cytotoxic effector cells and are able to kill autologous target cells and suppress HIV-1 replication in vitro.
Our data demonstrate the therapeutic potential of this CD40-targeting HIV candidate vaccine in inducing a broad repertoire of multifunctional T cells in patients.
PMCID: PMC3859846  PMID: 23615121
CD40; dendritic cell; HIV; T cell; vaccine
3.  Dendritic cell-based cancer therapeutic vaccines 
Immunity  2013;39(1):38-48.
The past decade has seen tremendous developments in novel cancer therapies, through targeting of tumor cell-intrinsic pathways whose activity is linked to genetic alterations, as well as the targeting of tumor cell-extrinsic factors such as growth factors. Furthermore, immunotherapies are entering the clinic at an unprecedented speed following the demonstration that T cells can efficiently reject tumors and that their anti-tumor activity can be enhanced with antibodies against immune regulatory molecules (checkpoints blockade). Current immunotherapy strategies include monoclonal antibodies against tumor cells or immune regulatory molecules, cell-based therapies such as adoptive transfer of ex vivo activated T cells and natural killer (NK) cells, and cancer vaccines. Herein, we discuss the immunological basis for therapeutic cancer vaccines and how the current understanding of dendritic cell (DC) and T cell biology might enable development of next-generation curative therapies for patients with cancer.
PMCID: PMC3788678  PMID: 23890062
4.  Human dendritic cell subsets in vaccination 
Current opinion in immunology  2013;25(3):396-402.
Owing to their properties, dendritic cells (DCs) are often called ‘nature's adjuvants’ and thus have become the natural targets for antigen delivery. DCs provide an essential link between the innate and the adaptive immune responses. DCs are at the center of the immune system owing to their ability to control both tolerance and immunity. DCs are thus key targets for both preventive and therapeutic vaccination. Herein, we will discuss recent progresses in our understanding of DC subsets physiology as it applies to vaccination.
PMCID: PMC3711217  PMID: 23725656
5.  Identification of the Key Differential Transcriptional Responses of Human Whole Blood Following TLR2 or TLR4 Ligation In-Vitro 
PLoS ONE  2014;9(5):e97702.
The use of human whole blood for transcriptomic analysis has potential advantages over the use of isolated immune cells for studying the transcriptional response to pathogens and their products. Whole blood stimulation can be carried out in a laboratory without the expertise or equipment to isolate immune cells from blood, with the added advantage of being able to undertake experiments using very small volumes of blood. Toll like receptors (TLRs) are a family of pattern recognition receptors which recognise highly conserved microbial products. Using the TLR2 ligand (Pam3CSK4) and the TLR4 ligand (LPS), human whole blood was stimulated for 0, 1, 3, 6, 12 or 24 hours at which times mRNA was isolated and a comparative microarray was undertaken. A common NFκB transcriptional programme was identified following both TLR2 and TLR4 ligation which peaked at between 3 to 6 hours including upregulation of many of the NFκB family members. In contrast an interferon transcriptional response was observed following TLR4 but not TLR2 ligation as early as 1 hour post stimulation and peaking at 6 hours. These results recapitulate the findings observed in previously published studies using isolated murine and human myeloid cells indicating that in vitro stimulated human whole blood can be used to interrogate the early transcriptional kinetic response of innate cells to TLR ligands. Our study demonstrates that a transcriptomic analysis of mRNA isolated from human whole blood can delineate both the temporal response and the key transcriptional differences following TLR2 and TLR4 ligation.
PMCID: PMC4026482  PMID: 24842522
6.  Human CD1c+ dendritic cells drive the differentiation of CD103+ CD8+ mucosal effector T cells via the cytokine TGF-β 
Immunity  2013;38(4):818-830.
In comparison to murine dendritic cells (DCs), less is known about the function of human DCs in tissues. Here, we analyzed, using lung tissues from humans and humanized mice, the role of human CD1c+ and CD141+ DCs in determining the type of CD8+ T cell immunity generated to live-attenuated influenza virus (LAIV) vaccine. We found that both lung DC subsets acquired influenza antigens in vivo and expanded specific cytotoxic CD8+ T cells in vitro. However, lung-tissue-resident CD1c+ DCs but not CD141+ DCs were able to drive CD103 expression on CD8+ T cells and promoted CD8+ T cell accumulation in lung epithelia in vitro and in vivo. CD1c+ DCs induction of CD103 expression was dependent on membrane-bound cytokine TGF-β1. Thus, CD1c+ and CD141+ DCs generate CD8+ T cells with different properties, and CD1c+ DCs specialize in the regulation of mucosal CD8+ T cells.
PMCID: PMC3639491  PMID: 23562160
7.  Systems Scale Interactive Exploration Reveals Quantitative and Qualitative Differences in Response to Influenza and Pneumococcal Vaccines 
Immunity  2013;38(4):831-844.
Systems immunology approaches were employed to investigate innate and adaptive immune responses to influenza and pneumococcal vaccines. These two non-live vaccines show different magnitudes of transcriptional responses at different time points after vaccination. Software solutions were developed to explore correlates of vaccine efficacy measured as antibody titers at day 28. These enabled a further dissection of transcriptional responses. Thus, the innate response, measured within hours in the peripheral blood, was dominated by an interferon transcriptional signature after influenza vaccination and by an inflammation signature after pneumococcal vaccination. Day 7 plasmablast responses induced by both vaccines was more pronounced after pneumococcal vaccination. Together, these results suggest that comparing global immune responses elicited by different vaccines will be critical to our understanding of the immune mechanisms underpinning successful vaccination.
PMCID: PMC3681204  PMID: 23601689
8.  Induction of ICOS+CXCR3+CXCR5+ TH Cells Correlates with Antibody Responses to Influenza Vaccination 
Science translational medicine  2013;5(176):176ra32.
Seasonal influenza vaccine protects 60 to 90% of healthy young adults from influenza infection. The immunological events that lead to the induction of protective antibody responses remain poorly understood in humans. We identified the type of CD4+ T cells associated with protective antibody responses after seasonal influenza vaccinations. The administration of trivalent split-virus influenza vaccines induced a temporary increase of CD4+ T cells expressing ICOS, which peaked at day 7, as did plasmablasts. The induction of ICOS was largely restricted to CD4+ T cells co-expressing the chemokine receptors CXCR3 and CXCR5, a subpopulation of circulating memory T follicular helper cells. Up to 60% of these ICOS+CXCR3+CXCR5+CD4+ T cells were specific for influenza antigens and expressed interleukin-2 (IL-2), IL-10, IL-21, and interferon-γ upon antigen stimulation. The increase of ICOS+CXCR3+CXCR5+CD4+ T cells in blood correlated with the increase of preexisting antibody titers, but not with the induction of primary antibody responses. Consistently, purified ICOS+CXCR3+CXCR5+CD4+ T cells efficiently induced memory B cells, but not naïve B cells, to differentiate into plasma cells that produce influenza-specific antibodies ex vivo. Thus, the emergence of blood ICOS+CXCR3+CXCR5+CD4+ T cells correlates with the development of protective antibody responses generated by memory B cells upon seasonal influenza vaccination.
PMCID: PMC3621097  PMID: 23486778
9.  Neutrophils come of age in chronic inflammation 
Current opinion in immunology  2012;24(6):671-677.
Neutrophils have long been known to participate in acute inflammation, but a role in chronic inflammatory and autoimmune diseases is now emerging. These cells are key players in the recognition and elimination of pathogens, but they also sense self components, including nucleic acids and products of sterile tissue damage. While this normally contributes to tissue repair, it can also lead to the release of highly immunogenic products that can trigger and/or amplify autoimmune pathogenic loops. Understanding the mechanisms that underlie neutrophil activation, migration, survival and their various forms of death in health and disease might provide us with new approaches to treat chronic inflammatory conditions.
PMCID: PMC3684162  PMID: 23127555
10.  Whole Blood Gene Expression Profiles to Assess Pathogenesis and Disease Severity in Infants with Respiratory Syncytial Virus Infection 
PLoS Medicine  2013;10(11):e1001549.
In this study, Mejias and colleagues found that specific blood RNA profiles of infants with RSV LRTI allowed for specific diagnosis, better understanding of disease pathogenesis, and better assessment of disease severity.
Please see later in the article for the Editors' Summary
Respiratory syncytial virus (RSV) is the leading cause of viral lower respiratory tract infection (LRTI) and hospitalization in infants. Mostly because of the incomplete understanding of the disease pathogenesis, there is no licensed vaccine, and treatment remains symptomatic. We analyzed whole blood transcriptional profiles to characterize the global host immune response to acute RSV LRTI in infants, to characterize its specificity compared with influenza and human rhinovirus (HRV) LRTI, and to identify biomarkers that can objectively assess RSV disease severity.
Methods and Findings
This was a prospective observational study over six respiratory seasons including a cohort of infants hospitalized with RSV (n = 135), HRV (n = 30), and influenza (n = 16) LRTI, and healthy age- and sex-matched controls (n = 39). A specific RSV transcriptional profile was identified in whole blood (training cohort, n = 45 infants; Dallas, Texas, US) and validated in three different cohorts (test cohort, n = 46, Dallas, Texas, US; validation cohort A, n = 16, Turku, Finland; validation cohort B, n = 28, Columbus, Ohio, US) with high sensitivity (94% [95% CI 87%–98%]) and specificity (98% [95% CI 88%–99%]). It classified infants with RSV LRTI versus HRV or influenza LRTI with 95% accuracy. The immune dysregulation induced by RSV (overexpression of neutrophil, inflammation, and interferon genes, and suppression of T and B cell genes) persisted beyond the acute disease, and immune dysregulation was greatly impaired in younger infants (<6 mo). We identified a genomic score that significantly correlated with outcomes of care including a clinical disease severity score and, more importantly, length of hospitalization and duration of supplemental O2.
Blood RNA profiles of infants with RSV LRTI allow specific diagnosis, better understanding of disease pathogenesis, and assessment of disease severity. This study opens new avenues for biomarker discovery and identification of potential therapeutic or preventive targets, and demonstrates that large microarray datasets can be translated into a biologically meaningful context and applied to the clinical setting.
Please see later in the article for the Editors' Summary
Editors' Summary
Lower respiratory tract infections (LRTIs)—bacterial and viral infections of the lungs and airways (the tubes that take oxygen-rich air to the lungs)—are major causes of illness and death in children worldwide. Pneumonia (infection of the lungs) alone is responsible for 14% of all child deaths. The leading cause of viral LTRIs in children is respiratory syncytial virus (RSV), which is readily transmitted from person to person by direct contact with nasal fluids or airborne droplets. Almost all children have an RSV infection before their second birthday, but most have only minor symptoms similar to those of a common cold and are cared for at home. Unfortunately, some children develop more serious conditions when they become infected with RSV, such as pneumonia or bronchiolitis (swelling and mucus build-up in the bronchioles, the smallest air passages in the lungs). These children have to be admitted to the hospital for supportive care—there is no specific treatment for RSV infection—such as the provision of supplemental oxygen.
Why Was This Study Done?
The lack of a treatment (and of a vaccine) for RSV is largely due to our incomplete understanding of the cellular events and reactions, including the host immune response, that occur during the development of an RSV infection (disease pathogenesis). Moreover, based on physical examination and available diagnostic tools, it is impossible to predict which children infected with RSV will develop a serious condition that requires hospitalization and which ones can be safely nursed at home. Here, the researchers use microarrays to analyze the global host response to acute RSV LTRI in infants, to define gene expression patterns that are specific to RSV infection rather than infection with other common respiratory viruses, and to identify biomarkers that indicate the severity of RSV infection. “Microarray” analysis allows researchers to examine gene expression patterns (“RNA transcriptional profiles”) in, for example, whole blood; a biomarker is a molecule whose level in bodily fluids or tissues indicates how a disease might develop and helps with patient classification.
What Did the Researchers Do and Find?
The researchers compared the RNA transcriptional profile in whole blood taken from children less than two years old hospitalized with RSV, human rhinovirus, or influenza virus infection (rhinovirus and influenza are two additional viral causes of LRTI), and from healthy infants. Using “statistical group comparisons,” they identified more than 2,000 transcripts that were differentially expressed in blood from 45 infants with RSV infection and from 14 healthy matched controls. Genes related to interferon function (interferons are released by host cells in response to the presence of disease-causing organisms) and neutrophil function (neutrophils are immune system cells that, like interferons, are involved in the innate immune response, the body's first line of defense against infection) were among the most overexpressed genes in infants infected with RSV. Genes regulating T and B cells (components of the adaptive immune response, the body's second-line of defense against infection) were among the most underexpressed genes. This specific transcriptional profile, which was validated in three additional groups of infants, accurately distinguished between infants infected with RSV and those infected with human rhinovirus or influenza virus. Finally, a “molecular distance to health” score (a numerical score that quantifies the transcriptional perturbation associated with an illness) was correlated with the clinical disease severity score of the study participants, with how long they needed supplemental oxygen, and with their duration of hospitalization.
What Do These Findings Mean?
These findings suggest that it might be possible to use whole blood RNA transcriptional profiles to distinguish between infants infected with RSV and those with other viruses that commonly cause LRTI. Moreover, if these findings can be replicated in more patients (including non-hospitalized children), gene expression profiling might provide a strategy for triaging patients with RSV infections when they first present to an emergency department and for monitoring clinical changes during the course of the infection, particularly given the development of molecular tools that might soon enable the “real time” acquisition of transcriptional profiles in the clinical setting. Finally, although certain aspects of the study design limit the accuracy and generalizability of the study's findings, these data provide new insights into the pathogenesis of RSV infection and open new avenues for the discovery of biomarkers for RSV infection and for the identification of therapeutic and preventative targets.
Additional Information
Please access these websites via the online version of this summary at
This study is further discussed in a PLOS Medicine Perspective by Peter Openshaw
The US Centers for Disease Control and Prevention provides information about RSV infection
The US National Heart, Lung, and Blood Institute provides information about the respiratory system and about RSV infections
The UK National Health Service Choices website provides information about bronchiolitis
The British Lung Foundation also provides information on RSV and on bronchiolitis
MedlinePlus provides links to other resources about RSV infections and about pneumonia (in English and Spanish); the MedlinePlus encyclopedia has a page on bronchiolitis (in English and Spanish)
PATH is an international non-profit organization investigating new RSV vaccines
PMCID: PMC3825655  PMID: 24265599
11.  Transcriptional network predicts viral set point during acute HIV-1 infection 
HIV-1-infected individuals with higher viral set points progress to AIDS more rapidly than those with lower set points. Predicting viral set point early following infection can contribute to our understanding of early control of HIV-1 replication, to predicting long-term clinical outcomes, and to the choice of optimal therapeutic regimens.
In a longitudinal study of 10 untreated HIV-1-infected patients, we used gene expression profiling of peripheral blood mononuclear cells to identify transcriptional networks for viral set point prediction. At each sampling time, a statistical analysis inferred the optimal transcriptional network that best predicted viral set point. We then assessed the accuracy of this transcriptional model by predicting viral set point in an independent cohort of 10 untreated HIV-1-infected patients from Malawi.
The gene network inferred at time of enrollment predicted viral set point 24 weeks later in the independent Malawian cohort with an accuracy of 87.5%. As expected, the predictive accuracy of the networks inferred at later time points was even greater, exceeding 90% after week 4. The composition of the inferred networks was largely conserved between time points. The 12 genes comprising this dynamic signature of viral set point implicated the involvement of two major canonical pathways: interferon signaling (p<0.0003) and membrane fraction (p<0.02). A silico knockout study showed that HLA-DRB1 and C4BPA may contribute to restricting HIV-1 replication.
Longitudinal gene expression profiling of peripheral blood mononuclear cells from patients with acute HIV-1 infection can be used to create transcriptional network models to early predict viral set point with a high degree of accuracy.
PMCID: PMC3534464  PMID: 22700869
Bioinformatics; HIV; systems biology; immunology; microbiology; HIV; microarray
12.  Functional diversity of human vaginal APC subsets in directing T cell responses 
Mucosal immunology  2012;6(3):626-638.
Human vaginal mucosa is the major entry site of sexually transmitted pathogens and thus has long been attractive as a site for mounting mucosal immunity. It is also known as a tolerogenic microenvironment. Here, we demonstrate that immune responses in the vagina are orchestrated by the functional diversity of four major antigen-presenting cell (APC) subsets. Langerhans cells (LCs) and CD14− lamina propria (LP)-DCs polarize CD4+ and CD8+ T cells toward Th2, whereas CD14+ LP-DCs and macrophages polarize CD4+ T cells toward Th1. Both LCs and CD14− LP-DCs are potent inducers of Th22. Due to their functional specialties and the different expression levels of pattern-recognition receptors on the APC subsets, microbial products do not bias them to elicit common types of immune responses (Th1 or Th2). To evoke desired types of adaptive immune responses in the human vagina, antigens may need to be targeted to proper APC subsets with right adjuvants.
PMCID: PMC3568194  PMID: 23131784
dendritic cells; vagina; mucosa; macrophages; T cell responses
13.  From IL-2 to IL-37: the expanding spectrum of anti-inflammatory cytokines 
Nature immunology  2012;13(10):925-931.
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.
PMCID: PMC3609707  PMID: 22990890
14.  H3N2 Influenza Virus Infection Induces Broadly Reactive Hemagglutinin Stalk Antibodies in Humans and Mice 
Journal of Virology  2013;87(8):4728-4737.
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.
PMCID: PMC3624338  PMID: 23408625
15.  Interferon Signature in the Blood in Inflammatory Common Variable Immune Deficiency 
PLoS ONE  2013;8(9):e74893.
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.
PMCID: PMC3775732  PMID: 24069364
16.  Non-covalent Assembly of Anti-Dendritic Cell Antibodies and Antigens for Evoking Immune Responses in vitro and in vivo1, 2 
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.
PMCID: PMC3424314  PMID: 22865916
18.  Mature Dendritic Cells Infiltrate the T Cell-Rich Region of Oral Mucosa in Chronic Periodontitis: In Situ, In Vivo, and In Vitro Studies1 
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.
PMCID: PMC3739284  PMID: 11591800
19.  Lipopolysaccharides from Distinct Pathogens Induce Different Classes of Immune Responses In Vivo1 
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.
PMCID: PMC3739327  PMID: 11673516
20.  Transcriptional Blood Signatures Distinguish Pulmonary Tuberculosis, Pulmonary Sarcoidosis, Pneumonias and Lung Cancers 
PLoS ONE  2013;8(8):e70630.
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.
PMCID: PMC3734176  PMID: 23940611
21.  CD34-derived dendritic cells transfected ex vivo with HIV-Gag mRNA induce polyfunctional T-cell responses in nonhuman primates 
European journal of immunology  2012;42(8):2019-2030.
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.
PMCID: PMC3649569  PMID: 22585548
Dendritic cells; Vaccination; Immune responses; Antigen presenting cells
22.  Tracking Interferon in Autoimmunity 
Immunity  2012;36(1):7-9.
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.
PMCID: PMC3694564  PMID: 22284415
23.  Cancer immunotherapy via dendritic cells 
Nature reviews. Cancer  2012;12(4):265-277.
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.
PMCID: PMC3433802  PMID: 22437871
24.  Macrophages induce differentiation of plasma cells through CXCL10/IP-10 
The Journal of Experimental Medicine  2012;209(10):1813-1823.
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.
PMCID: PMC3457728  PMID: 22987802
25.  ZnT8-Specific CD4+ T Cells Display Distinct Cytokine Expression Profiles between Type 1 Diabetes Patients and Healthy Adults 
PLoS ONE  2013;8(2):e55595.
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.
PMCID: PMC3563599  PMID: 23390544

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