The respiratory tract is a major portal for pathogens. The bronchoalveolar macrophage, positioned at the mucosal surface, recognizes """"""""pathogen associated molecular patterns (PAMPs)"""""""" through """"""""pattern recognition receptors (PRRs)."""""""" A family of mammalian PRRs, """"""""Toll-like receptors"""""""" (TLRs), are transmembrane signaling molecules that respond to diverse PAMPs. Gram negative lipopolysaccharide (LPS) stimulates cells through TLR4 to elicit a strongly proinflammatory pattern of gene expression, resulting in a """"""""Th1-type"""""""" cytokine milieu. Respiratory syncytial virus (RSV) is the leading cause of pneumonia and bronchiolitis in infants and young children worldwide, and has recently been attributed to increased morbidity and mortality in the elderly and immunosuppressed. The RSV fusion (F) protein is also a TLR4 agonist. Prophylactic administration of anti-F antibodies to high-risk infants is highly protective. In a failed clinical trial in the 1960's, a formalin-inactivated RSV (FI-RSV) vaccine led to exacerbated RSV disease, findings we have recapitulated in the cotton rat (S. hispidus), assessed by pulmonary histopathology and airway hyperreactivity. During the first cycle of this grant, we identified cyclooxygenase-2 and prostanoids as key therapeutic targets for RSV-induced lung pathology. We found that vaccination of cotton rats with the original FI-RSV used in the failed trials, newly formulated with a non-toxic adjuvant and TLR4 agonist, monophosphoryl lipid A (MPL), suppressed FI-RSV vaccine-enhanced disease by blunting the mixed Th1- and Th2-type """"""""cytokine storm"""""""" that is elicited upon RSV infection of vaccinated subjects. In vitro, purified F protein activation of NF-?B and IL-8 secretion in HEK293T cells is TLR4-, MD-2-, and CD14-dependent, and transfectants that express TLR4 proteins with one or both of two single nucleotide polymorphisms (SNPs), previously associated with LPS-hyporesponsiveness, were significantly less responsive to purified RSV F protein, under conditions of equal TLR expression. Importantly, we identified a highly significant overrepresentation of these TLR4 SNPs in DNA samples derived from a case series of high-risk infants and children with documented RSV infection. These data strongly support our overarching hypothesis that TLR4 plays a central role in the innate immune response to RSV and imply that initial engagement of TLR4 is required for development of a protective, adaptive immune response, rather than a pathological one. This proposal details innovative experimental approaches that will (i) lead to development a safe and effective RSV F protein subunit vaccine, (ii) lead to development of therapeutic intervention strategies based on a characterization of the interaction of F protein with the TLR4/MD-2/CD14 complex and examine the role(s) of TLR4 signaling in RSV infection/protection. It is expected that at the completion of this grant, we will have identified strategies that may lead to development of a RSV vaccine and new therapeutics for mitigating the pathologic host response to RSV.

Public Health Relevance

Toll-like receptor 4 (TLR4) detects many microbial structures and host danger signals during the early phases of the host immune response to infection. Respiratory Syncytial Virus (RSV) expresses a protein called F protein that stimulates cells using TLR4. We have recently shown that a previously failed vaccine can be made safe and partially protective by including a TLR4-activating agent in the vaccine. Our proposal seeks to test a new subunit vaccine and to identify new ways to treat RSV infection.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI057575-10
Application #
8277400
Study Section
Innate Immunity and Inflammation Study Section (III)
Program Officer
Kim, Sonnie
Project Start
2004-01-01
Project End
2014-05-31
Budget Start
2012-06-01
Budget End
2013-05-31
Support Year
10
Fiscal Year
2012
Total Cost
$524,620
Indirect Cost
$117,990
Name
Sigmovir Biosystems, Inc.
Department
Type
DUNS #
965180610
City
Rockville
State
MD
Country
United States
Zip Code
20850
Blanco, Jorge C G; Pletneva, Lioubov M; Oue, Raymonde O et al. (2015) Maternal transfer of RSV immunity in cotton rats vaccinated during pregnancy. Vaccine 33:5371-5379
Shirey, K A; Lai, W; Pletneva, L M et al. (2014) Role of the lipoxygenase pathway in RSV-induced alternatively activated macrophages leading to resolution of lung pathology. Mucosal Immunol 7:549-57
Patel, Mira C; Shirey, Kari Ann; Pletneva, Lioubov M et al. (2014) Novel drugs targeting Toll-like receptors for antiviral therapy. Future Virol 9:811-829
Shirey, Kari Ann; Lai, Wendy; Pletneva, Lioubov M et al. (2014) Agents that increase AAM differentiation blunt RSV-mediated lung pathology. J Leukoc Biol 96:951-5
Blanco, Jorge Cg; Boukhvalova, Marina S; Perez, Daniel R et al. (2014) Modeling Human Respiratory Viral Infections in the Cotton Rat (Sigmodon hispidus). J Antivir Antiretrovir 6:40-42
Blanco, Jorge C G; Boukhvalova, Marina S; Pletneva, Lioubov M et al. (2014) A recombinant anchorless respiratory syncytial virus (RSV) fusion (F) protein/monophosphoryl lipid A (MPL) vaccine protects against RSV-induced replication and lung pathology. Vaccine 32:1495-500
Boukhvalova, Marina S; Blanco, Jorge C G (2013) The cotton rat Sigmodon hispidus model of respiratory syncytial virus infection. Curr Top Microbiol Immunol 372:347-58
Shirey, Kari Ann; Lai, Wendy; Scott, Alison J et al. (2013) The TLR4 antagonist Eritoran protects mice from lethal influenza infection. Nature 497:498-502
Rallabhandi, Prasad; Phillips, Rachel L; Boukhvalova, Marina S et al. (2012) Respiratory syncytial virus fusion protein-induced toll-like receptor 4 (TLR4) signaling is inhibited by the TLR4 antagonists Rhodobacter sphaeroides lipopolysaccharide and eritoran (E5564) and requires direct interaction with MD-2. MBio 3:
Boukhvalova, Marina S; Sotomayor, Talia B; Point, Ryan C et al. (2010) Activation of interferon response through toll-like receptor 3 impacts viral pathogenesis and pulmonary toll-like receptor expression during respiratory syncytial virus and influenza infections in the cotton rat Sigmodon hispidus model. J Interferon Cytokine Res 30:229-42

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