Monoclonal antibody with hemagglutination, immobilization, and neutralization activities defines an immunodominant, 47,000 mol wt, surface-exposed immunogen of Treponema pallidum (Nichols).

Abstract

Radioimmunoprecipitation (RIP) analyses performed on 125I-surface-labeled Treponema pallidum cells using various immune sera revealed the presence of six major surface antigens (immunogens) with apparent molecular weights of 47 K, 36 K, 34 K, 32 K, 29 K, and 13 K. Among these, the 47 K surface antigen was most abundant. Radioimmunoprecipitation assays using 125I-labeled T. phagedenis biotype Reiter or immunoblot analyses using the same strain, failed to reveal the presence of the 47 K mol wt antigen in the representative nonpathogenic treponeme. Preabsorption of anti-T. pallidum immune rabbit serum (IRS) with the Reiter organism did not remove anti-T. pallidum antibodies from immune serum that reacted with the 47 K mol wt immunogen or other immunogens of T. pallidum present in the characteristic antigenic profile. Monoclonal antibodies (mAb) directed specifically against the 47 K mol wt immunogen of T. pallidum also failed to react with an analogous 47 K mol wt component in Treponema phagedenis biotype Reiter, further suggesting the unique presence of this antigen in pathogenic treponemes. The presence of the 47 K mol wt surface immunogen in pathogenic treponemes other than T. pallidum subspecies pallidum was also observed (43). Anti-47 K immunogen mAb was nonreactive against rabbit IgG or IgM. mAb directed specifically against the 47 K mol wt immunogen of T. pallidum was examined for strategic functional activities. It was found to be reactive in the microhemagglutination assay for T. pallidum antibodies, the T. pallidum immobilization test, and was found to be capable of significant blockage of attachment of virulent T. pallidum to host cells in tissue culture. Additional significant biological activity for the anti-47 K mol wt immunogen mAb was revealed through results of the in vitro-in vivo neutralization test of Bishop and Miller, in which a 99% or 100% neutralizing activity was demonstrated. The combined data of this study suggest that the 47 K mol wt immunogen of T. pallidum represents an abundant, immunodominant, surface-exposed immunogen possessing potential biological importance in the pathogenesis and immunology of T. pallidum infection. These studies serve to establish the first functionally defined immunogen for T. pallidum, which may represent the major immunogen of the organism.

Crystal Structure of the Tp34 (TP0971) Lipoprotein of Treponema pallidum

“…The encapsulation method stabilizes the fragile outer membrane of T. pallidum during antibody exposure and washing treatments. Mouse monoclonal anti-Tp47 (clone 11E3) (43) and mouse monoclonal anti-Tp34 (44) were diluted 1:20 and added directly to 1 ml of aliquots of microdroplets with or without 0.15% (v/v) Triton X-100. The microdroplets were incubated overnight at 4°C.…”

Crystal Structure of the 47-kDa Lipoprotein of Treponema pallidum Reveals a Novel Penicillin-binding Protein

“…On this basis, it could be conjectured that Tp47 is a ␤-lactamase. However, from a biological perspective, this notion is strongly inconsistent with the exquisite sensitivity of T. pallidum to ␤-lactams, particularly when the extraordinary abundance of Tp47 in T. pallidum is taken into account (41). Thus, the biological relevance of the putative Tp47 in vitro ␤-lactamase activity remains suspect, as it may be of little or no consequence to the biology of T. pallidum in vivo (i.e.…”

“…Biological Significance and Implications-Tp47 was first noted in early molecular studies of T. pallidum, due largely to its abundance and profound immunogenicity (41). It thus initially was targeted for study as a potential syphilis serodiagnostic reagent (41,44), and many newer generation serological tests for syphilis now include Tp47 as a principal, if not sole, antigenic component (45,46).…”

“…It thus initially was targeted for study as a potential syphilis serodiagnostic reagent (41,44), and many newer generation serological tests for syphilis now include Tp47 as a principal, if not sole, antigenic component (45,46). Tp47 initially also was thought to be an outer membrane protein (41).…”

“…It thus initially was targeted for study as a potential syphilis serodiagnostic reagent (41,44), and many newer generation serological tests for syphilis now include Tp47 as a principal, if not sole, antigenic component (45,46). Tp47 initially also was thought to be an outer membrane protein (41). However, a more extensive body of work, which has taken into account the previously unrecognized fragility of the unusual T. pallidum outer membrane (1,47), later supported that Tp47 likely is a cytoplasmic membrane lipoprotein that, according to convention, would protrude into the periplasmic space (47,48).…”