Previous studies have demonstrated that the outer membrane of Treponema pallidum is physically labile and has the ability to resist binding of specific antibody. It is hypothesized that these properties are the result of a paucity of integral membrane proteins in the outer membrane and that the resistance to binding specific antibody constitutes a major treponemal defense against the host humoral immune response. Phase partitioning with the nonionic detergent Triton X-114 has been used to identify a group of pathogen-specific, putative integral membrane proteins (detergent-phase proteins) in T. pallidum. Among the detergent- phase proteins (DPPs) are several previously unrecognized and/or poorly characterized antigens, including 15- and 17-kDa polypeptides which are extremely immunoreactive with human syphilitic serum. Murine monclonal antibodies will be raised against the DPPs, and individual proteins within the detergent phase will be purified. Monoclonal and polyclonal antibodies generated against these proteins will be used to determine their precise intracellular locations by immunocytochemical localization on ultrathin cryosections and by analysis of isolated intact outer and cytoplasmic membranes. Freeze-fracture electron microscopy will be performed as an alternative method for determining the relative protein contentts of the outer and cytoplasmic membranes. Structure-function analysis of DPPs will be performed to identify biologically significant structural domains. Proteolytic digests of DPPs will be examined by immunoblotting and by solid-phase immunoassy using monoclonal and polyclonal antibodies. Antibodies to DPPs will be assayed for biological activity against virulent T. pallidum. The 15- and 17- kDa DPPs, which are quantitatively minor components of the detergent-phase mixture, will be cloned and expressed in E. coli. The proposed studies will provide new insights into T. pallidum ultrastructure, into the organism's host-parasite relationships, and into the contributions of newly characterized membrane proteins to the complex immunopathology of syphilis.

National Institute of Health (NIH)
National Institute of Allergy and Infectious Diseases (NIAID)
First Independent Research Support & Transition (FIRST) Awards (R29)
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Bacteriology and Mycology Subcommittee 1 (BM)
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University of Texas Sw Medical Center Dallas
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Luthra, Amit; Anand, Arvind; Hawley, Kelly L et al. (2015) A Homology Model Reveals Novel Structural Features and an Immunodominant Surface Loop/Opsonic Target in the Treponema pallidum BamA Ortholog TP_0326. J Bacteriol 197:1906-20
Luthra, Amit; Anand, Arvind; Radolf, Justin D (2015) Treponema pallidum in Gel Microdroplets: A Method for Topological Analysis of BamA (TP0326) and Localization of Rare Outer Membrane Proteins. Methods Mol Biol 1329:67-75
Anand, Arvind; LeDoyt, Morgan; Karanian, Carson et al. (2015) Bipartite Topology of Treponema pallidum Repeat Proteins C/D and I: OUTER MEMBRANE INSERTION, TRIMERIZATION, AND PORIN FUNCTION REQUIRE A C-TERMINAL ?-BARREL DOMAIN. J Biol Chem 290:12313-31
Kenedy, Melisha R; Luthra, Amit; Anand, Arvind et al. (2014) Structural modeling and physicochemical characterization provide evidence that P66 forms a ?-barrel in the Borrelia burgdorferi outer membrane. J Bacteriol 196:859-72
Anand, Arvind; Luthra, Amit; Edmond, Maxwell E et al. (2013) The major outer sheath protein (Msp) of Treponema denticola has a bipartite domain architecture and exists as periplasmic and outer membrane-spanning conformers. J Bacteriol 195:2060-71
Silver, Adam C; Dunne, Dana W; Zeiss, Caroline J et al. (2013) MyD88 deficiency markedly worsens tissue inflammation and bacterial clearance in mice infected with Treponema pallidum, the agent of syphilis. PLoS One 8:e71388
Cruz, Adriana R; Ramirez, Lady G; Zuluaga, Ana V et al. (2012) Immune evasion and recognition of the syphilis spirochete in blood and skin of secondary syphilis patients: two immunologically distinct compartments. PLoS Negl Trop Dis 6:e1717
Anand, Arvind; Luthra, Amit; Dunham-Ems, Star et al. (2012) TprC/D (Tp0117/131), a trimeric, pore-forming rare outer membrane protein of Treponema pallidum, has a bipartite domain structure. J Bacteriol 194:2321-33
Hoover, Karen W; Radolf, Justin D (2011) Serodiagnosis of syphilis in the recombinant era: reversal of fortune. J Infect Dis 204:1295-6
Luthra, Amit; Zhu, Guangyu; Desrosiers, Daniel C et al. (2011) The transition from closed to open conformation of Treponema pallidum outer membrane-associated lipoprotein TP0453 involves membrane sensing and integration by two amphipathic helices. J Biol Chem 286:41656-68

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