Abstract

Syphilis, caused by Treponema pallidum, continues to be a significant public health problem and has been demonstrated to augment the spread of HIV. New means of prevention of syphilis, including vaccine development, are needed. In order to approach vaccine development in a rational way, antigens must be prioritized for examination based upon their functions in pathogenesis and immunity. The opsonization of T. pallidum by antibodies is crucial for bacterial clearance and for macrophage-mediated killing. Therefore, a recombinant expression library will be screened for clones reacting with opsonic rabbit serum (ORS). The ORS is immune rabbit serum from which many """"""""irrelevant"""""""" antibodies (those not important for opsonization, including antibodies to the major lipoproteins and the endoflagella) have been adsorbed; full opsonic capacity is retained following adsorption. Selected clones will be prioritized for further examination based upon their lack of reactivity with non-opsonic antisera (anti-Borrelia, anti-Leptospira). Promising clones will be sequenced and their full open reading frames (ORFs) will be identified in the newly released T. pallidum genome sequence. The ORFs will be expressed as recombinant proteins and antibodies will be produced. These antibodies will be used to determine if the antigens are located on the surface of T. pallidum. The role of these molecules in attachment of T. pallidum to eucaryotic cells, an early step in pathogenesis, will be examined by testing the ability of the antibodies to block adherence in vitro. The role of the antigens in opsonization will be examined by testing the antisera for their ability to facilitate phagocytosis of T. pallidum by rabbit peritoneal macrophages. Antigens that appear to be promising, based upon in their surface localization or their role in opsonization or cytoadherence, will be tested for their ability to protect rabbits from challenge with T. pallidum. This focused approach for selecting antigens of interest, based upon functions known to be important in pathogenesis and immunity, will identify important virulence factors of T. pallidum and will identify potential vaccine candidates for further study.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI043456-02
Application #
6170545
Study Section
Bacteriology and Mycology Subcommittee 2 (BM)
Program Officer
Quackenbush, Robert L
Project Start
1999-09-28
Project End
2003-08-31
Budget Start
2000-09-01
Budget End
2001-08-31
Support Year
2
Fiscal Year
2000
Total Cost
$256,153
Indirect Cost

  Institution

Name
University of Washington
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
135646524
City
Seattle
State
WA
Country
United States
Zip Code
98195

  Publications

Leader, Brandon T; Godornes, Charmie; VanVoorhis, Wesley C et al. (2007) CD4+ lymphocytes and gamma interferon predominate in local immune responses in early experimental syphilis. Infect Immun 75:3021-6
LaFond, Rebecca E; Molini, Barbara J; Van Voorhis, Wesley C et al. (2006) Antigenic variation of TprK V regions abrogates specific antibody binding in syphilis. Infect Immun 74:6244-51
LaFond, Rebecca E; Centurion-Lara, Arturo; Godornes, Charmie et al. (2006) TprK sequence diversity accumulates during infection of rabbits with Treponema pallidum subsp. pallidum Nichols strain. Infect Immun 74:1896-906
Sun, Eileen S; Molini, Barbara J; Barrett, Lynn K et al. (2004) Subfamily I Treponema pallidum repeat protein family: sequence variation and immunity. Microbes Infect 6:725-37
Giacani, Lorenzo; Sun, Eileen S; Hevner, Karin et al. (2004) Tpr homologs in Treponema paraluiscuniculi Cuniculi A strain. Infect Immun 72:6561-76
Centurion-Lara, Arturo; LaFond, Rebecca E; Hevner, Karin et al. (2004) Gene conversion: a mechanism for generation of heterogeneity in the tprK gene of Treponema pallidum during infection. Mol Microbiol 52:1579-96
Leader, Brandon T; Hevner, Karin; Molini, Barbara J et al. (2003) Antibody responses elicited against the Treponema pallidum repeat proteins differ during infection with different isolates of Treponema pallidum subsp. pallidum. Infect Immun 71:6054-7
Van Voorhis, Wesley C; Barrett, Lynn K; Lukehart, Sheila A et al. (2003) Serodiagnosis of syphilis: antibodies to recombinant Tp0453, Tp92, and Gpd proteins are sensitive and specific indicators of infection by Treponema pallidum. J Clin Microbiol 41:3668-74
Morgan, Cecilia A; Lukehart, Sheila A; Van Voorhis, Wesley C (2003) Protection against syphilis correlates with specificity of antibodies to the variable regions of Treponema pallidum repeat protein K. Infect Immun 71:5605-12
LaFond, Rebecca E; Centurion-Lara, Arturo; Godornes, Charmie et al. (2003) Sequence diversity of Treponema pallidum subsp. pallidum tprK in human syphilis lesions and rabbit-propagated isolates. J Bacteriol 185:6262-8

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