The role of LPS-TLR4 signaling in live vaccine-induced protective responses

Summary

Principal Investigator: Egil Lien
Affiliation: University of Massachusetts Medical School
Country: USA
Abstract: Live vaccines have a long history for providing efficient protection against subsequent infectious challenge. However, the mechanisms leading to protection are in many cases not well defined. Our goal is to define mechanisms for immune protection by Gram-negative bacterial vaccine strains, using novel Yersinia pestis strains as model systems. The gram-negative bacterium Yersinia pestis is the causative agent of plague. Currently there is no available licensed plague vaccine, and exploratory vaccines have variable ability to protect against pneumonic disease, the form expected after a bioterror attack. We have developed a new method for the generation of efficient vaccine strains for protection against plague and potentially other microorganisms, based upon enhancement of inherent bacterial Toll-like receptor (TLR)-4 mediated adjuvant activity. Similar to various other gram-negative bacteria, Y. pestis produces a lipopolysaccharide (LPS) with low stimulatory ability at 37:C. TLR4 is the cellular receptor for LPS via its lipid A. We generated a new Y. pestis strain expressing LpxL, an E. coli lipid A biosynthesis enzyme, and found this to produce a potent LPS at 37:C. This strain is avirulent in mice by peripheral inoculation, due to induction of antibacterial innate immune mechanisms via TLR4, a pathway also associated with strong adjuvant effects. Our results indicate that vaccination of mice with the Y. pestis LpxL strain induces full protection against both subcutaneous and intranasal challenge of mice with virulent bacteria, mimicking bubonic and pneumonic plague. Our main hypotheses are that many live bacterial vaccine strains containing LPS with increased potency are efficient vaccines, and that the increased TLR4 signaling will provide enhanced adaptive immune responses. We propose to determine mechanisms influencing the vaccine efficacy using live and killed Y. pestis producing a potent LPS, by comparing to strains without increased TLR4 stimulation, testing both in vitro and in vivo responses. Both existing and novel attenuated strains will be used. Relying on primary dendritic and T cells and genetically deficient mice, we will study TLR signaling pathways leading to dendritic cell activation in vivo and in vitro, antigen presentation and T cell subset activation. We will analyze vaccine effects against both subcutaneous and intranasal infection. The completion of these studies will provide information on the mechanism by which vaccine strains towards Gram-negative infections may act. Incorporation of TLR- stimulating adjuvant activity directly into immune-evading pathogens may constitute a novel method for attenuation and generation of vaccines. PUBLIC HEALTH RELEVANCE: This proposal will identify mechanisms by which live vaccines against some bacterial infections work. We will use novel avirulent, immunostimulatory strains of the plague bacillus Yersinia pestis as a model system. Our results may help in the design of future vaccines against plague and other infectious diseases.
Funding Period: -------------------- - --------------------
more information: NIH RePORT

Top Publications

  1. pmc MD-2-mediated ionic interactions between lipid A and TLR4 are essential for receptor activation
    Jianmin Meng
    Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
    J Biol Chem 285:8695-702. 2010
  2. pmc Differential gene expression downstream of Toll-like receptors (TLRs): role of c-Src and activating transcription factor 3 (ATF3)
    Thuy Thanh Nguyen
    Department of Laboratory Medicine, Children s and Women s Health, Norwegian University of Science and Technology, N 7006 Trondheim, Norway
    J Biol Chem 285:17011-9. 2010
  3. pmc Inflammation and fibrosis during Chlamydia pneumoniae infection is regulated by IL-1 and the NLRP3/ASC inflammasome
    Xianbao He
    Section of Infectious Diseases, Department of Medicine, Boston Medical Center, Boston University School of Medicine, Boston, MA 02118, USA
    J Immunol 184:5743-54. 2010
  4. pmc NLRP3 inflammasomes are required for atherogenesis and activated by cholesterol crystals
    Peter Duewell
    Department of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
    Nature 464:1357-61. 2010
  5. doi The Rab11a GTPase controls Toll-like receptor 4-induced activation of interferon regulatory factor-3 on phagosomes
    Harald Husebye
    Norwegian University of Science and Technology, Department of Cancer Research and Molecular Medicine, N 7489 Trondheim, Norway
    Immunity 33:583-96. 2010
  6. pmc The NLRP12 inflammasome recognizes Yersinia pestis
    Gregory I Vladimer
    Division of Infectious Diseases and Immunology, UMass Medical School, Worcester, MA 01605, USA
    Immunity 37:96-107. 2012
  7. pmc Inflammasomes and host defenses against bacterial infections
    Gregory I Vladimer
    Division of Infectious Diseases and Immunology, Department of Medicine, UMass Medical School, Worcester, MA 01605, USA
    Curr Opin Microbiol 16:23-31. 2013
  8. ncbi (De-) oiling inflammasomes
    Robyn Marty-Roix
    Division of Infectious Diseases and Immunology, Program in Innate Immunity, Department of Medicine, UMass Medical School, Worcester, MA 01605, USA
    Immunity 38:1088-90. 2013
  9. pmc D27-pLpxL, an avirulent strain of Yersinia pestis, primes T cells that protect against pneumonic plague
    Frank M Szaba
    Trudeau Institute, Saranac Lake, New York 12983, USA
    Infect Immun 77:4295-304. 2009

Detail Information

Publications9

  1. pmc MD-2-mediated ionic interactions between lipid A and TLR4 are essential for receptor activation
    Jianmin Meng
    Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
    J Biol Chem 285:8695-702. 2010
    ....
  2. pmc Differential gene expression downstream of Toll-like receptors (TLRs): role of c-Src and activating transcription factor 3 (ATF3)
    Thuy Thanh Nguyen
    Department of Laboratory Medicine, Children s and Women s Health, Norwegian University of Science and Technology, N 7006 Trondheim, Norway
    J Biol Chem 285:17011-9. 2010
    ..These results demonstrate functional specificity for c-Src in TLR-stimulated responses and suggest that c-Src modulation and ATF3 activity may contribute to differential regulation of IRF-3- versus IRF-5-mediated gene expression...
  3. pmc Inflammation and fibrosis during Chlamydia pneumoniae infection is regulated by IL-1 and the NLRP3/ASC inflammasome
    Xianbao He
    Section of Infectious Diseases, Department of Medicine, Boston Medical Center, Boston University School of Medicine, Boston, MA 02118, USA
    J Immunol 184:5743-54. 2010
    ..pneumoniae directly activates the NLRP3/ASC inflammasome, leading to the release of biologically active IL-1beta, and that concurrent IL-1 signaling is required for optimal host defense against acute bacterial pneumonia...
  4. pmc NLRP3 inflammasomes are required for atherogenesis and activated by cholesterol crystals
    Peter Duewell
    Department of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
    Nature 464:1357-61. 2010
    ..These findings provide new insights into the pathogenesis of atherosclerosis and indicate new potential molecular targets for the therapy of this disease...
  5. doi The Rab11a GTPase controls Toll-like receptor 4-induced activation of interferon regulatory factor-3 on phagosomes
    Harald Husebye
    Norwegian University of Science and Technology, Department of Cancer Research and Molecular Medicine, N 7489 Trondheim, Norway
    Immunity 33:583-96. 2010
    ..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 IRF3 activation from this compartment...
  6. pmc The NLRP12 inflammasome recognizes Yersinia pestis
    Gregory I Vladimer
    Division of Infectious Diseases and Immunology, UMass Medical School, Worcester, MA 01605, USA
    Immunity 37:96-107. 2012
    ..These studies reveal a role for NLRP12 in host resistance against pathogens. Minimizing NLRP12 inflammasome activation may have been a central factor in evolution of the high virulence of Y. pestis...
  7. pmc Inflammasomes and host defenses against bacterial infections
    Gregory I Vladimer
    Division of Infectious Diseases and Immunology, Department of Medicine, UMass Medical School, Worcester, MA 01605, USA
    Curr Opin Microbiol 16:23-31. 2013
    ..Future research will determine how specific inflammasome components pair up in optimal responses to specific bacteria...
  8. ncbi (De-) oiling inflammasomes
    Robyn Marty-Roix
    Division of Infectious Diseases and Immunology, Program in Innate Immunity, Department of Medicine, UMass Medical School, Worcester, MA 01605, USA
    Immunity 38:1088-90. 2013
    ..In this issue of Immunity, Yan et al. (2013) suggest that omega-3 fatty acids commonly found in marine oils can suppress activation of NLRP3 and NLRP1b inflammasomes. ..
  9. pmc D27-pLpxL, an avirulent strain of Yersinia pestis, primes T cells that protect against pneumonic plague
    Frank M Szaba
    Trudeau Institute, Saranac Lake, New York 12983, USA
    Infect Immun 77:4295-304. 2009
    ..This study describes a new model for studying T-cell-mediated protection against pneumonic plague and demonstrates the capacity for live, highly attenuated, Y. pestis vaccine strains to prime protective memory T-cell responses safely...