Assessment of cell-surface exposure and vaccinogenic potentials of Treponema pallidum candidate outer membrane proteins.
Syphilis, a sexually transmitted infection caused by the spirochetal bacterium Treponema pallidum, remains a global public health problem. T. pallidum is believed to be an extracellular pathogen and, as such, the identification of T. pallidum outer membrane proteins that could serve as targets for opsonic or bactericidal antibodies has remained a high research priority for vaccine development. However, the identification of T. pallidum outer membrane proteins has remained highly elusive. Recent studies and bioinformatics have implicated four treponemal proteins as potential outer membrane proteins (TP0155, TP0326, TP0483 and TP0956). Indirect immunofluorescence assays performed on treponemes encapsulated within agarose gel microdroplets failed to provide evidence that any of these four molecules were surface-exposed in T. pallidum. Second, recombinant fusion proteins corresponding to all four candidate outer membrane proteins were used separately, or in combination, to vaccinate New Zealand White rabbits. Despite achieving high titers (>1:50,000) of serum antibodies, none of the rabbits displayed chancre immunity after intradermal challenge with viable T. pallidum.
Tomson
Farol L
FL
Department of Microbiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390, USA.
Conley
Patrick G
PG
Norgard
Michael V
MV
Hagman
Kayla E
KE
D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D001425:Bacterial Outer Membrane Proteins / Q000032:analysis / Q000276:immunology*; D001428:Bacterial Vaccines / Q000276:immunology*; D002601:Chancre / Q000517:prevention & control; D019084:Fluorescent Antibody Technique, Indirect; D008297:Male; D011817:Rabbits; D011993:Recombinant Fusion Proteins / Q000276:immunology; D013587:Syphilis / Q000276:immunology* / Q000517:prevention & control*; D014210:Treponema pallidum / Q000737:chemistry / Q000276:immunology*; D022223:Vaccines, Subunit / Q000276:immunology*; D014614:Vaccines, Synthetic / Q000276:immunology*
D000907:Antibodies, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001428:Bacterial Vaccines; D011993:Recombinant Fusion Proteins; D022223:Vaccines, Subunit; D014614:Vaccines, Synthetic