Thursday, October 28, 2010

Hot off the presses! Oct 29 Immunity

The Oct 29 issue of the Immunity is now up on Pubget (About Immunity): if you're at a subscribing institution, just click the link in the latest link at the home page. (Note you'll only be able to get all the PDFs in the issue if your institution subscribes to Pubget.)

Latest Articles Include:

  • A Decade of Vaccines: Integrating Immunology and Vaccinology for Rational Vaccine Design
    - Immunity 33(4):437-440 (2010)
    Vaccination stands as one of the most successful public health measures of the last century. New approaches will be needed, however, to develop highly effective vaccines to prevent tuberculosis, HIV-AIDS, and malaria and to eradicate polio. Current advances in immunology and technology have set the stage for rational vaccine design to begin a "Decade of Vaccines."
  • Vaccines and the Future of Human Immunology
    - Immunity 33(4):441-450 (2010)
    In this issue of Immunity, a collection of detailed reviews summarizes needs, opportunities, and roadblocks to the development of new vaccines, all in the context of our current knowledge and understanding of key aspects of immune function and microbial interactions with the host. This Perspective is designed to provide a broad overview that discusses our present limitations in designing effective novel vaccines for diseases that do not typically induce robust resistance in infected individuals and how the addition of a systems-level, multiplexed approach to the analysis of the human immune system can complement traditional highly focused research efforts to accelerate our progress toward this goal and the improvement of human health.
  • From Vaccines to Memory and Back
    - Immunity 33(4):451-463 (2010)
    Vaccines work by eliciting an immune response and consequent immunological memory that mediates protection from infection or disease. Recently, new methods have been developed to dissect the immune response in experimental animals and humans, which have led to increased understanding of the molecular mechanisms that control differentiation and maintenance of memory T and B cells. In this review we will provide an overview of the cellular organization of immune memory and underline some of the outstanding questions on immunological memory and how they pertain to vaccination strategies. Finally we will discuss how we can learn about antigen design from the interrogation of our memory T and B cells—a journey from vaccines to memory and back.
  • Designing Vaccines Based on Biology of Human Dendritic Cell Subsets
    - Immunity 33(4):464-478 (2010)
    The effective vaccines developed against a variety of infectious agents, including polio, measles, and hepatitis B, represent major achievements in medicine. These vaccines, usually composed of microbial antigens, are often associated with an adjuvant that activates dendritic cells (DCs). Many infectious diseases are still in need of an effective vaccine including HIV, malaria, hepatitis C, and tuberculosis. In some cases, the induction of cellular rather than humoral responses may be more important because the goal is to control and eliminate the existing infection rather than to prevent it. Our increased understanding of the mechanisms of antigen presentation, particularly with the description of DC subsets with distinct functions, as well as their plasticity in responding to extrinsic signals, represent opportunities to develop novel vaccines. In addition, we foresee that this increased knowledge will permit us to design vaccines that will reprogram the immune syste! m to intervene therapeutically in cancer, allergy, and autoimmunity.
  • Vaccination Strategies to Promote Mucosal Antibody Responses
    - Immunity 33(4):479-491 (2010)
    There are great interest and demand for the development of vaccines to prevent and treat diverse microbial infections. Mucosal vaccines elicit immune protection by stimulating the production of antibodies at mucosal surfaces and systemic districts. Being positioned in close proximity to a large community of commensal microbes, the mucosal immune system deploys a heterogeneous population of cells and a complex regulatory network to maintain the balance between surveillance and tolerance. A successful mucosal vaccine relies on leveraging the functions of these immune cells and regulatory components. We review the important cellular interactions and molecular pathways underlying the induction and regulation of mucosal antibody responses and discuss their implications on mucosal vaccination.
  • Vaccine Adjuvants: Putting Innate Immunity to Work
    - Immunity 33(4):492-503 (2010)
    Adjuvants enhance immunity to vaccines and experimental antigens by a variety of mechanisms. In the past decade, many receptors and signaling pathways in the innate immune system have been defined and these innate responses strongly influence the adaptive immune response. The focus of this review is to delineate the innate mechanisms by which adjuvants mediate their effects. We highlight how adjuvants can be used to influence the magnitude and alter the quality of the adaptive response in order to provide maximum protection against specific pathogens. Despite the impressive success of currently approved adjuvants for generating immunity to viral and bacterial infections, there remains a need for improved adjuvants that enhance protective antibody responses, especially in populations that respond poorly to current vaccines. However, the larger challenge is to develop vaccines that generate strong T cell immunity with purified or recombinant vaccine antigens.
  • Immunologic Basis of Vaccine Vectors
    - Immunity 33(4):504-515 (2010)
    Efforts to make vaccines against infectious diseases as well as immunotherapies for cancer, autoimmune diseases and allergy have utilized a variety of heterologous expression systems, including viral and bacterial vectors, as well as DNA and RNA constructs. This review explores the immunologic rationale and provides an update of insights obtained from preclinical and clinical studies of such vaccines.
  • Systems Vaccinology
    - Immunity 33(4):516-529 (2010)
    Vaccination is one of the greatest triumphs of modern medicine, yet we remain largely ignorant of the mechanisms by which successful vaccines stimulate protective immunity. Two recent advances are beginning to illuminate such mechanisms: realization of the pivotal role of the innate immune system in sensing microbes and stimulating adaptive immunity, and advances in systems biology. Recent studies have used systems biology approaches to obtain a global picture of the immune responses to vaccination in humans. This has enabled the identification of early innate signatures that predict the immunogenicity of vaccines, and identification of potentially novel mechanisms of immune regulation. Here, we review these advances and critically examine the potential opportunities and challenges posed by systems biology in vaccine development.
  • Reverse Vaccinology: Developing Vaccines in the Era of Genomics
    - Immunity 33(4):530-541 (2010)
    The sequence of microbial genomes made all potential antigens of each pathogen available for vaccine development. This increased by orders of magnitude potential vaccine targets in bacteria, parasites, and large viruses and revealed virtually all their CD4+ and CD8+ T cell epitopes. The genomic information was first used for the development of a vaccine against serogroup B meningococcus, and it is now being used for several other bacterial vaccines. In this review, we will first summarize the impact that genome sequencing has had on vaccine development, and then we will analyze how the genomic information can help further our understanding of immunity to infection or vaccination and lead to the design of better vaccines by diving into the world of T cell immunity.
  • Induction of Immunity to Human Immunodeficiency Virus Type-1 by Vaccination
    - Immunity 33(4):542-554 (2010)
    Recent findings have brought optimism that development of a successful human immunodeficiency virus type-1 (HIV-1) vaccine lies within reach. Studies of early events in HIV-1 infection have revealed when and where HIV-1 is potentially vulnerable to vaccine-targeted immune responses. With technical advances in human antibody production, clues about how antibodies recognize HIV-1 envelope proteins have uncovered new targets for immunogen design. A recent vaccine regimen has shown modest efficacy against HIV-1 acquisition. However, inducing long-term T and B cell memory and coping with HIV-1 diversity remain high priorities. Mediators of innate immunity may play pivotal roles in blocking infection and shaping immunity; vaccine strategies to capture these activities are under investigation. Challenges remain in integrating basic, preclinical and clinical research to improve predictions of types of immunity associated with vaccine efficacy, to apply these insights to immuno! gen design, and to accelerate evaluation of vaccine efficacy in persons at-risk for infection.
  • Malaria Vaccine Design: Immunological Considerations
    - Immunity 33(4):555-566 (2010)
    The concept of a malaria vaccine has sparked great interest for decades; however, the challenge is proving to be a difficult one. Immune dysregulation by Plasmodium and the ability of the parasite to mutate critical epitopes in surface antigens have proved to be strong defense weapons. This has led to reconsideration of polyvalent and whole parasite strategies and ways to enhance cellular immunity to malaria that may be more likely to target conserved antigens and an expanded repertoire of antigens. These and other concepts will be discussed in this review.
  • Future Vaccination Strategies against Tuberculosis: Thinking outside the Box
    - Immunity 33(4):567-577 (2010)
    With almost a dozen vaccine candidates in clinical trials, tuberculosis (TB) research and development is finally reaping the first fruits of its labors. Vaccine candidates in clinical trials may prevent TB disease reactivation by efficiently containing the pathogen Mycobacterium tuberculosis (Mtb). Future research should target vaccines that achieve sterile eradication of Mtb or even prevent stable infection. These are ambitious goals that can be reached only by highly cooperative engagement of basic immunologists, vaccinologists, and clinical researchers—or in other words, by translation from basic immunology to vaccine research and development, as well as reverse translation of insights from clinical trials back to hypothesis-driven research in the basic laboratory. Here, we review current and future strategies toward the rational design of novel vaccines against TB, as well as the progress made thus far, and the hurdles that need to be overcome in the near and dis! tant future.
  • Recycling Endosomes and TLR Signaling— The Rab11 GTPase Leads the Way
    - Immunity 33(4):578-580 (2010)
    The ability of Toll-like receptors (TLRs) to activate innate immunity depends on their transport to pathogen-containing organelles. In this issue of Immunity, Husebye et al. (2010) report that delivery of TLR4 to phagosomes occurs via a recycling endosome intermediate, which is controlled by the GTPase Rab11a.
  • A Flt3L Encounter: mTOR Signaling in Dendritic Cells
    - Immunity 33(4):580-582 (2010)
    The signaling pathway of the cytokine Flt3L in dendritic cells (DCs) is poorly defined. In this issue of Immunity, Sathaliyawala et al. (2010) report that the kinase mTOR functions as a mediator of Flt3L signaling in the development and homeostasis of DCs, particularly of the CD8+ and CD103+ DCs.
  • The Rab11a GTPase Controls Toll-like Receptor 4-Induced Activation of Interferon Regulatory Factor-3 on Phagosomes
    - Immunity 33(4):583-596 (2010)
    Toll-like receptor 4 (TLR4) is indispensable for recognition of Gram-negative bacteria. We described a trafficking pathway for TLR4 from the endocytic recycling compartment (ERC) to E. coli phagosomes. We found a prominent colocalization between TLR4 and the small GTPase Rab11a in the ERC, and Rab11a was involved in the recruitment of TLR4 to phagosomes in a process requiring TLR4 signaling. Also, Toll-receptor-associated molecule (TRAM) and interferon regulatory factor-3 (IRF3) localized to E. coli phagosomes and internalization of E. coli was required for a robust interferon-β induction. Suppression of Rab11a reduced TLR4 in the ERC and on phagosomes leading to inhibition of the IRF3 signaling pathway induced by E. coli, whereas activation of the transcription factor NF-κB was unaffected. Moreover, Rab11a silencing reduced the amount of TRAM on phagosomes. Thus, Rab11a is an important regulator of TLR4 and TRAM transport to E. coli phagosomes thereby controlling IR! F3 activation from this compartment.
  • Mammalian Target of Rapamycin Controls Dendritic Cell Development Downstream of Flt3 Ligand Signaling
    - Immunity 33(4):597-606 (2010)
    Dendritic cells (DCs) comprise distinct functional subsets including CD8− and CD8+ classical DCs (cDCs) and interferon-secreting plasmacytoid DCs (pDCs). The cytokine Flt3 ligand (Flt3L) controls the development of DCs and is particularly important for the pDC and CD8+ cDC and their CD103+ tissue counterparts. We report that mammalian target of rapamycin (mTOR) inhibitor rapamycin impaired Flt3L-driven DC development in vitro, with the pDCs and CD8+-like cDCs most profoundly affected. Conversely, deletion of the phosphoinositide 3-kinase (PI3K)-mTOR negative regulator Pten facilitated Flt3L-driven DC development in culture. DC-specific Pten targeting in vivo caused the expansion of CD8+ and CD103+ cDC numbers, which was reversible by rapamycin. The increased CD8+ cDC numbers caused by Pten deletion correlated with increased susceptibility to the intracellular pathogen Listeria. Thus, PI3K-mTOR signaling downstream of Flt3L controls DC development, and its restriction! by Pten ensures optimal DC pool size and subset composition.
  • MicroRNA-155 Promotes Autoimmune Inflammation by Enhancing Inflammatory T Cell Development
    - Immunity 33(4):607-619 (2010)
    Mammalian noncoding microRNAs (miRNAs) are a class of gene regulators that have been linked to immune system function. Here, we have investigated the role of miR-155 during an autoimmune inflammatory disease. Consistent with a positive role for miR-155 in mediating inflammatory responses, Mir155−/− mice were highly resistant to experimental autoimmune encephalomyelitis (EAE). miR-155 functions in the hematopoietic compartment to promote the development of inflammatory T cells including the T helper 17 (Th17) cell and Th1 cell subsets. Furthermore, the major contribution of miR-155 to EAE was CD4+ T cell intrinsic, whereas miR-155 was also required for optimum dendritic cell production of cytokines that promoted Th17 cell formation. Our study shows that one aspect of miR-155 function is the promotion of T cell-dependent tissue inflammation, suggesting that miR-155 might be a promising therapeutic target for the treatment of autoimmune disorders.
  • Carcinoembryonic Antigen-Related Cell Adhesion Molecule-1 Regulates Granulopoiesis by Inhibition of Granulocyte Colony-Stimulating Factor Receptor
    - Immunity 33(4):620-631 (2010)
    Although carcinoembryonic antigen-related cell adhesion moclecule-1 (CEACAM1) is an activation marker for neutrophils and delays neutrophil apoptosis, the role of CEACAM1 in granulopoiesis and neutrophil-dependent host immune responses has not been investigated. CEACAM1 expression correlated with granulocytic differentiation, and Ceacam1−/− mice developed neutrophilia because of loss of the Src-homology-phosphatase-1 (SHP-1)-dependent inhibition of granulocyte colony-stimulating factor receptor (G-CSFR) signal transducer and activator of transcription (Stat3) pathway provided by CEACAM1. Moreover, Ceacam1−/− mice were hypersensitive to Listeria Monocytogenes (LM) infection with an accelerated mortality. Reintroduction of CEACAM1 into Ceacam1−/− bone marrow restored normal granulopoiesis and host sensitivity to LM infection, while mutation of its immunoreceptor tyrosine-based inhibitory motifs (ITIMs) abrogated this restoration. shRNA-mediated reduction of S! tat3 amounts rescued normal granulopoiesis, attenuating host sensitivity to LM infection in Ceacam1−/− mice. Thus, CEACAM1 acted as a coinhibitory receptor for G-CSFR regulating granulopoiesis and host innate immune response to bacterial infections.
  • Intravital Imaging Reveals Distinct Dynamics for Natural Killer and CD8+ T Cells during Tumor Regression
    - Immunity 33(4):632-644 (2010)
    Recognition of NKG2D ligands by natural killer (NK) cells plays an important role during antitumoral responses. To address how NKG2D engagement affects intratumoral NK cell dynamics, we performed intravital microscopy in a Rae-1β-expressing solid tumor. This NKG2D ligand drove NK cell accumulation, activation, and motility within the tumor. NK cells established mainly dynamic contacts with their targets during tumor regression. In sharp contrast, cytotoxic T lymphocytes (CTLs) formed stable contacts in tumors expressing their cognate antigen. Similar behaviors were observed during effector functions in lymph nodes. In vitro, contacts between NK cells and their targets were cytotoxic but did not elicit sustained calcium influx nor adhesion, whereas CTL contact stability was critically dependent on extracellular calcium entry. Altogether, our results offer mechanistic insight into how NK cells and CTLs can exert cytotoxic activity with remarkably different contact dynam! ics.

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