This application addresses the compelling need to develop new and improved vaccine adjuvants for stimulating protective immunity at mucosal surfaces. The proposal involves a consortium arrangement between the University of Louisville, the University at Buffalo, and the Hauptman-Woodward Institute, and brings together complementary and integrated expertise in vaccine adjuvant research, structural and molecular biology, and induction of mucosal immunity. Studies by this group have succeeded to dissociate useful adjuvant properties from the toxicity of LT-IIb, an AB5-type heat-labile enterotoxin of Escherichia coli. Specifically, the recombinantly expressed B pentameric subunit of LT-IIb (LT-IIb-B5) not only lacks enterotoxicity but, strikingly, can activate the Toll-like receptor (TLR)-2/TLR1 signaling complex and stimulate antibody responses to co-administered vaccine proteins. Proof-of-concept preliminary studies have shown that certain engineered point-substitution mutations in the active region of LT-IIb-B5 enhance its ability to interact with TLR2 and TLR1. The overall objective of this application is to better characterize the physical and functional interaction of LT-IIb-B5 with the TLR2/TLR1 heterodimer, engineer improved versions of LT-IIb-B5 in terms of TLR2/TLR1-mediated adjuvanticity, and develop potential adjuvants through studies in preclinical models of vaccination against oral infection. This will be accomplished through appropriate and innovative molecular biological, structural, and immunological studies outlined in the following four specific aims: 1) To rationally engineer enhanced TLR2-interactive versions of LT-IIb-B5. 2) To structurally characterize the LT-IIb- B5-TLR2/TLR1 interaction using small-angle X-ray scattering (SAXS). 3) To evaluate the engineered LT-IIb-B5 mutants for in vitro TLR2/TLR1-dependent immunostimulatory activities. 4) To determine the ability of LT-IIb-B5 and improved engineered versions thereof to induce protective immunity in vivo. The generated data will form the basis for the long-term goal which is to establish LT-IIb-B5 and improved engineered derivatives as effective adjuvants in vaccine formulations against pathogens which colonize or invade via oral, respiratory, or urogenital mucosal surfaces.

Public Health Relevance

The objective of this application is to rationally engineer novel Toll-like receptor-dependent mucosal adjuvants. These constructs will be evaluated for their capacity to stimulate protective immunity using appropriate preclinical mouse models. The focus of this proposal is on a novel vaccine against periodontitis, an oral inflammatory disease with an impact on systemic health, although the developed mucosal adjuvants can also be used in vaccine formulations against pathogens which colonize or invade via oral, respiratory, or urogenital mucosal surfaces. This work is timely and important given the paucity of safe and effective vaccine adjuvants and the tremendous health impact of infectious diseases.

Agency
National Institute of Health (NIH)
Institute
National Institute of Dental & Craniofacial Research (NIDCR)
Type
Research Project (R01)
Project #
5R01DE017138-10
Application #
8508910
Study Section
Oral, Dental and Craniofacial Sciences Study Section (ODCS)
Program Officer
Burgoon, Penny W
Project Start
2006-02-01
Project End
2015-08-31
Budget Start
2013-09-01
Budget End
2014-08-31
Support Year
10
Fiscal Year
2013
Total Cost
$372,315
Indirect Cost
$93,079
Name
University of Pennsylvania
Department
Microbiology/Immun/Virology
Type
Schools of Dentistry
DUNS #
042250712
City
Philadelphia
State
PA
Country
United States
Zip Code
19104
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Hajishengallis, George (2015) Periodontitis: from microbial immune subversion to systemic inflammation. Nat Rev Immunol 15:30-44
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Hajishengallis, G; Sahingur, S E (2014) Novel inflammatory pathways in periodontitis. Adv Dent Res 26:23-9
Maekawa, Tomoki; Abe, Toshiharu; Hajishengallis, Evlambia et al. (2014) Genetic and intervention studies implicating complement C3 as a major target for the treatment of periodontitis. J Immunol 192:6020-7
Moutsopoulos, Niki M; Konkel, Joanne; Sarmadi, Mojgan et al. (2014) Defective neutrophil recruitment in leukocyte adhesion deficiency type I disease causes local IL-17-driven inflammatory bone loss. Sci Transl Med 6:229ra40
Hajishengallis, George (2014) Immunomicrobial pathogenesis of periodontitis: keystones, pathobionts, and host response. Trends Immunol 35:3-11
Abe, Toshiharu; Shin, Jieun; Hosur, Kavita et al. (2014) Regulation of osteoclast homeostasis and inflammatory bone loss by MFG-E8. J Immunol 193:1383-91

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