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Treponema pallidum major sheath protein homologue Tpr K is a target of opsonic antibody and the protective immune response.

Centurion-Lara A, Castro C, Barrett L, Cameron C, Mostowfi M, Van Voorhis WC, Lukehart SA - J. Exp. Med. (1999)

Bottom Line: Both approaches led to the identification of a polymorphic multicopy gene family with predicted amino acid homology to the major sheath protein of Treponema denticola.Immunization of rabbits with the purified recombinant variable domain of Tpr K provides significant protection against infection with the Nichols strain of T. pallidum.This gene family is hypothesized to be central to pathogenesis and immunity during syphilis infection.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, University of Washington, Seattle, Washington 98195, USA. acentur@u.washington.edu

ABSTRACT
We have identified a family of genes that code for targets for opsonic antibody and protective immunity in T. pallidum subspecies pallidum using two different approaches, subtraction hybridization and differential immunologic screening of a T. pallidum genomic library. Both approaches led to the identification of a polymorphic multicopy gene family with predicted amino acid homology to the major sheath protein of Treponema denticola. One of the members of this gene family, tpr K, codes for a protein that is predicted to have a cleavable signal peptide and be located in the outer membrane of the bacterium. Reverse transcription polymerase chain reaction analysis of T. pallidum reveals that Tpr K is preferentially transcribed in the Nichols strain of T. pallidum. Antibodies directed to purified recombinant variable domain of Tpr K can opsonize T. pallidum, Nichols strain, for phagocytosis, supporting the hypothesis that this portion of the protein is exposed at the surface of the treponeme. Immunization of rabbits with the purified recombinant variable domain of Tpr K provides significant protection against infection with the Nichols strain of T. pallidum. This gene family is hypothesized to be central to pathogenesis and immunity during syphilis infection.

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Opsonization of T. pallidum by antisera to recombinant Tpr K  variable domain. Columns represent the percentage of rabbit peritoneal  macrophages ingesting T. pallidum, Nichols strain, after 4 h of incubation  with viable T. pallidum (107 treponemes and 2 × 106 macrophages) in  RPMI with 10% final concentration of NRS plus 1% final concentration  of test or control antiserum. Ingested treponemes were visualized by indirect immunofluorescence staining. Triplicate cultures were prepared for  each experiment and were scored for each condition by a blinded observer. Column values represent means ± SEM of four separate experiments. Significant opsonization is determined by comparison with the  NRS values (Student's t test) and P values are shown. IRS, pooled syphilitic immune rabbit sera; Tpr K, anti-recombinant Tpr K variable domain.
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Figure 4: Opsonization of T. pallidum by antisera to recombinant Tpr K variable domain. Columns represent the percentage of rabbit peritoneal macrophages ingesting T. pallidum, Nichols strain, after 4 h of incubation with viable T. pallidum (107 treponemes and 2 × 106 macrophages) in RPMI with 10% final concentration of NRS plus 1% final concentration of test or control antiserum. Ingested treponemes were visualized by indirect immunofluorescence staining. Triplicate cultures were prepared for each experiment and were scored for each condition by a blinded observer. Column values represent means ± SEM of four separate experiments. Significant opsonization is determined by comparison with the NRS values (Student's t test) and P values are shown. IRS, pooled syphilitic immune rabbit sera; Tpr K, anti-recombinant Tpr K variable domain.

Mentions: The variable domain of Tpr K was examined as a potential target of opsonic antibodies for three reasons: RT-PCR analysis suggests that it is preferentially expressed in the Nichols strain; it is predicted to have a cleavable signal peptide and be localized to the outer membrane; and structural analysis supports the hypothesis that the hydrophilic regions are exposed on the external face of the outer membrane. In addition, the immunologic screening of the expression library identified Tpr K as being reactive with ORS and not with non-ORS. Antisera obtained from the animals immunized with the recombinant Tpr K variable domain were tested in four separate experiments for opsonic activity. As shown in Fig. 4, anti-Tpr K variable domain was significantly opsonic for the Nichols strain of T. pallidum, compared with NRS. These results strongly support the hypothesis that Tpr K is expressed in the Nichols strain and that the variable domain is exposed at the surface of the bacterium.


Treponema pallidum major sheath protein homologue Tpr K is a target of opsonic antibody and the protective immune response.

Centurion-Lara A, Castro C, Barrett L, Cameron C, Mostowfi M, Van Voorhis WC, Lukehart SA - J. Exp. Med. (1999)

Opsonization of T. pallidum by antisera to recombinant Tpr K  variable domain. Columns represent the percentage of rabbit peritoneal  macrophages ingesting T. pallidum, Nichols strain, after 4 h of incubation  with viable T. pallidum (107 treponemes and 2 × 106 macrophages) in  RPMI with 10% final concentration of NRS plus 1% final concentration  of test or control antiserum. Ingested treponemes were visualized by indirect immunofluorescence staining. Triplicate cultures were prepared for  each experiment and were scored for each condition by a blinded observer. Column values represent means ± SEM of four separate experiments. Significant opsonization is determined by comparison with the  NRS values (Student's t test) and P values are shown. IRS, pooled syphilitic immune rabbit sera; Tpr K, anti-recombinant Tpr K variable domain.
© Copyright Policy
Related In: Results  -  Collection

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Figure 4: Opsonization of T. pallidum by antisera to recombinant Tpr K variable domain. Columns represent the percentage of rabbit peritoneal macrophages ingesting T. pallidum, Nichols strain, after 4 h of incubation with viable T. pallidum (107 treponemes and 2 × 106 macrophages) in RPMI with 10% final concentration of NRS plus 1% final concentration of test or control antiserum. Ingested treponemes were visualized by indirect immunofluorescence staining. Triplicate cultures were prepared for each experiment and were scored for each condition by a blinded observer. Column values represent means ± SEM of four separate experiments. Significant opsonization is determined by comparison with the NRS values (Student's t test) and P values are shown. IRS, pooled syphilitic immune rabbit sera; Tpr K, anti-recombinant Tpr K variable domain.
Mentions: The variable domain of Tpr K was examined as a potential target of opsonic antibodies for three reasons: RT-PCR analysis suggests that it is preferentially expressed in the Nichols strain; it is predicted to have a cleavable signal peptide and be localized to the outer membrane; and structural analysis supports the hypothesis that the hydrophilic regions are exposed on the external face of the outer membrane. In addition, the immunologic screening of the expression library identified Tpr K as being reactive with ORS and not with non-ORS. Antisera obtained from the animals immunized with the recombinant Tpr K variable domain were tested in four separate experiments for opsonic activity. As shown in Fig. 4, anti-Tpr K variable domain was significantly opsonic for the Nichols strain of T. pallidum, compared with NRS. These results strongly support the hypothesis that Tpr K is expressed in the Nichols strain and that the variable domain is exposed at the surface of the bacterium.

Bottom Line: Both approaches led to the identification of a polymorphic multicopy gene family with predicted amino acid homology to the major sheath protein of Treponema denticola.Immunization of rabbits with the purified recombinant variable domain of Tpr K provides significant protection against infection with the Nichols strain of T. pallidum.This gene family is hypothesized to be central to pathogenesis and immunity during syphilis infection.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, University of Washington, Seattle, Washington 98195, USA. acentur@u.washington.edu

ABSTRACT
We have identified a family of genes that code for targets for opsonic antibody and protective immunity in T. pallidum subspecies pallidum using two different approaches, subtraction hybridization and differential immunologic screening of a T. pallidum genomic library. Both approaches led to the identification of a polymorphic multicopy gene family with predicted amino acid homology to the major sheath protein of Treponema denticola. One of the members of this gene family, tpr K, codes for a protein that is predicted to have a cleavable signal peptide and be located in the outer membrane of the bacterium. Reverse transcription polymerase chain reaction analysis of T. pallidum reveals that Tpr K is preferentially transcribed in the Nichols strain of T. pallidum. Antibodies directed to purified recombinant variable domain of Tpr K can opsonize T. pallidum, Nichols strain, for phagocytosis, supporting the hypothesis that this portion of the protein is exposed at the surface of the treponeme. Immunization of rabbits with the purified recombinant variable domain of Tpr K provides significant protection against infection with the Nichols strain of T. pallidum. This gene family is hypothesized to be central to pathogenesis and immunity during syphilis infection.

Show MeSH
Related in: MedlinePlus