title: Major integral membrane protein immunogens of Treponema pallidum are proteolipids.
abstract: A number of the major pathogen-specific immunogens of Treponema pallidum were characterized recently as amphiphilic, integral membrane proteins by phase partitioning with Triton X-114 (J. D. Radolf, N. R. Chamberlain, A. Clausell, and M. V. Norgard. Infect. Immun. 56:490-498, 1988). In the present study, we demonstrated that the same membrane immunogens (designated as detergent phase proteins [DPPs]) become radiolabeled upon in vitro incubation of T. pallidum with various 3H-labeled fatty acids. Radioimmunoprecipitation with a monoclonal antibody confirmed that the 3H-labeled 47-kilodalton protein corresponded to the well-characterized treponemal antigen with the identical apparent molecular mass. Failure to detect 3H-labeled DPPs following incubation with erythromycin confirmed that protein acylation required de novo protein synthesis by the bacteria. When treponemes were incubated with [3H]myristate, [3H]palmitate, or [3H]oleate, radiolabeled proteins corresponding to the DPPs were detected upon autoradiography. Demonstration that a number of the abundant membrane immunogens of T. pallidum are proteolipids provides information to help clarify their membrane association(s) and may serve to explain their extraordinary immunogenicity.
authors.affiliation: Department of Microbiology, University of Texas Southwestern Medical Center, Dallas 75235.
authors.forename: N R
authors.initials: NR
authors.lastname: Chamberlain
authors.forename: M E
authors.initials: ME
authors.lastname: Brandt
authors.forename: A L
authors.initials: AL
authors.lastname: Erwin
authors.forename: J D
authors.initials: JD
authors.lastname: Radolf
authors.forename: M V
authors.initials: MV
authors.lastname: Norgard
mesh_terms: D000818:Animals; D000942:Antigens, Bacterial / Q000032:analysis*; D001426:Bacterial Proteins / Q000276:immunology / Q000302:isolation & purification* / Q000378:metabolism; D005227:Fatty Acids / Q000378:metabolism; D008565:Membrane Proteins / Q000276:immunology / Q000302:isolation & purification* / Q000378:metabolism; D011510:Proteolipids / Q000276:immunology / Q000302:isolation & purification* / Q000378:metabolism; D011817:Rabbits; D013329:Structure-Activity Relationship; D014210:Treponema pallidum / Q000276:immunology*; D014316:Tritium
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D005227:Fatty Acids; D008565:Membrane Proteins; D011510:Proteolipids; D014316:Tritium