{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T01:21:59Z","timestamp":1760059319881,"version":"build-2065373602"},"reference-count":49,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2025,6,5]],"date-time":"2025-06-05T00:00:00Z","timestamp":1749081600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100000060","name":"NIH\/NIAID","doi-asserted-by":"publisher","award":["U19AI144133","R01AI139265"],"award-info":[{"award-number":["U19AI144133","R01AI139265"]}],"id":[{"id":"10.13039\/100000060","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Diagnostics"],"abstract":"<jats:p>Background\/Objectives: Syphilis, a chronic sexually transmitted disease caused by the spirochete Treponema\u00a0pallidum subspecies pallidum (T. pallidum), is still endemic in low- and middle-income countries and has been resurgent for decades in many high-income nations despite being treatable. Improving our understanding of syphilis pathogenesis, immunology, and T. pallidum biology could result in novel measures to curtail syphilis spread, including new therapeutics, a preventive vaccine, and, most importantly, improved diagnostics. Methods: Using overlapping synthetic peptides spanning the length of the T. pallidum Tp0435 mature lipoprotein, an abundant antigen known to induce an immunodominant humoral response during both natural and experimental infection, we evaluated which Tp0435 linear epitopes are most significantly recognized by antibodies from an infected host. Specifically, we used sera from 63 patients with syphilis at different stages, sera from non-syphilis patients (n = 40), and sera longitudinally collected from 10 rabbits infected with either the Nichols or SS14 isolates of T. pallidum, which represent the model strains for the two known circulating clades of this pathogen, to further evaluate the use of this animal model for syphilis studies. Recognized amino acid sequences were then mapped to the experimentally determined Tp0435 structure. Results: Reactive epitopes in both serum groups mapped predominantly to the \u03b1-helix preceding Tp0435 soluble \u03b2-barrel and the loops of the barrel. Conclusions: In the current effort to improve current syphilis diagnostics, the peptides corresponding to these immunodominant epitopes could help develop epitope-based assays such as peptide-based ELISAs and lateral flow point-of-care tests to improve the performance of treponemal tests and expedite diagnosis in low-income settings, where the infection is still a significant concern for public health and access to facilities with laboratories equipped to perform complex procedures might be challenging.<\/jats:p>","DOI":"10.3390\/diagnostics15111443","type":"journal-article","created":{"date-parts":[[2025,6,6]],"date-time":"2025-06-06T03:52:28Z","timestamp":1749181948000},"page":"1443","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["B-Cell Epitope Mapping of the Treponema pallidum Tp0435 Immunodominant Lipoprotein for Peptide-Based Syphilis Diagnostics"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0009-0008-2632-0762","authenticated-orcid":false,"given":"Jessica L.","family":"Keane","sequence":"first","affiliation":[{"name":"Department of Medicine, Division of Allergy and Infectious Diseases, University of Washington, Harborview Medical Center, 300 9th Ave, Seattle, WA 98104, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6872-5591","authenticated-orcid":false,"given":"Mahashweta","family":"Bose","sequence":"additional","affiliation":[{"name":"Department of Medicine, Division of Allergy and Infectious Diseases, University of Washington, Harborview Medical Center, 300 9th Ave, Seattle, WA 98104, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Barbara J.","family":"Molini","sequence":"additional","affiliation":[{"name":"Department of Medicine, Division of Allergy and Infectious Diseases, University of Washington, Harborview Medical Center, 300 9th Ave, Seattle, WA 98104, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2836-0174","authenticated-orcid":false,"given":"Kelika A.","family":"Konda","sequence":"additional","affiliation":[{"name":"Keck School of Medicine, University of Southern California, 1975 Zonal Ave, Los Angeles, CA 90033, USA"},{"name":"Center for Interdisciplinary Studies in Sexuality, AIDS and Society, Universidad Peruana Cayetano Heredia, Av. Honorio Delgado 430, Lima 15102, Peru"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Silver K.","family":"Vargas","sequence":"additional","affiliation":[{"name":"Center for Interdisciplinary Studies in Sexuality, AIDS and Society, Universidad Peruana Cayetano Heredia, Av. Honorio Delgado 430, Lima 15102, Peru"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Michael","family":"Reyes Diaz","sequence":"additional","affiliation":[{"name":"Center for Interdisciplinary Studies in Sexuality, AIDS and Society, Universidad Peruana Cayetano Heredia, Av. Honorio Delgado 430, Lima 15102, Peru"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Carlos F.","family":"Caceres","sequence":"additional","affiliation":[{"name":"Center for Interdisciplinary Studies in Sexuality, AIDS and Society, Universidad Peruana Cayetano Heredia, Av. Honorio Delgado 430, Lima 15102, Peru"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jeffrey D.","family":"Klausner","sequence":"additional","affiliation":[{"name":"Keck School of Medicine, University of Southern California, 1975 Zonal Ave, Los Angeles, CA 90033, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2736-3341","authenticated-orcid":false,"given":"Rebecca S.","family":"Treger","sequence":"additional","affiliation":[{"name":"Department of Laboratory Medicine and Pathology, University of Washington, 1959 NE Pacific St., Seattle, WA 98195, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3889-7274","authenticated-orcid":false,"given":"Lorenzo","family":"Giacani","sequence":"additional","affiliation":[{"name":"Department of Medicine, Division of Allergy and Infectious Diseases, University of Washington, Harborview Medical Center, 300 9th Ave, Seattle, WA 98104, USA"},{"name":"Department of Global Health, University of Washington, Harborview Medical Center, 300 9th Ave, Seattle, WA 98104, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2025,6,5]]},"reference":[{"key":"ref_1","unstructured":"Radolf, J.D., and Lukehart, S.A. (2006). Pathogenic Treponema: Molecular and Cellular Biology, Caister Academic Press."},{"key":"ref_2","unstructured":"WHO (2025, January 05). World Health Organization. Syphilis. Available online: https:\/\/www.who.int\/news-room\/fact-sheets\/detail\/syphilis."},{"key":"ref_3","unstructured":"ECDC (2024). Syphilis, Annual Epidemiological Report for 2022."},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Chen, T., Wan, B., Wang, M., Lin, S., Wu, Y., and Huang, J. (2023). Evaluating the global, regional, and national impact of syphilis: Results from the global burden of disease study 2019. Sci. Rep., 13.","DOI":"10.1038\/s41598-023-38294-4"},{"key":"ref_5","unstructured":"CDC (2024). Sexually Transmitted Infections (STI) Surveillance, 2023."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"e1110","DOI":"10.1016\/S2214-109X(21)00221-7","article-title":"Prevalence of syphilis among men who have sex with men: A global systematic review and meta-analysis from 2000\u20132020","volume":"9","author":"Tsuboi","year":"2021","journal-title":"Lancet Glob. Health"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"e24","DOI":"10.1016\/S1473-3099(23)00314-6","article-title":"Resurgence of congenital syphilis: New strategies against an old foe","volume":"24","author":"Moseley","year":"2024","journal-title":"Lancet Infect. Dis."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Gilmour, L.S., and Walls, T. (2023). Congenital Syphilis: A Review of Global Epidemiology. Clin. Microbiol. Rev., 36.","DOI":"10.1128\/cmr.00126-22"},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Haynes, A.M., Giacani, L., Mayans, M.V., Ubals, M., Nieto, C., P\u00e9rez-Ma\u00f1\u00e1, C., Quint\u00f3, L., Romeis, E., and Mitj\u00e0, O. (2021). Efficacy of linezolid on Treponema pallidum, the syphilis agent: A preclinical study. EBioMedicine, 65.","DOI":"10.1016\/j.ebiom.2021.103281"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"7676","DOI":"10.1016\/j.vaccine.2022.11.002","article-title":"Immunization with a tri-antigen syphilis vaccine significantly attenuates chancre development, reduces bacterial load, and inhibits dissemination of Treponema pallidum","volume":"40","author":"Lukehart","year":"2022","journal-title":"Vaccine"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"110","DOI":"10.1136\/sextrans-2015-052219","article-title":"Painful and multiple anogenital lesions are common in men with Treponema pallidum PCR-positive primary syphilis without herpes simplex virus coinfection: A cross-sectional clinic-based study","volume":"92","author":"Towns","year":"2016","journal-title":"Sex. Transm. Infect."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1510","DOI":"10.1001\/jama.290.11.1510","article-title":"Update on syphilis: Resurgence of an old problem","volume":"290","author":"Golden","year":"2003","journal-title":"JAMA"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"e22890","DOI":"10.1002\/jcla.22890","article-title":"PCR detection for syphilis diagnosis: Status and prospects","volume":"33","author":"Zhou","year":"2019","journal-title":"J. Clin. Lab. Anal."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"S4","DOI":"10.1093\/cid\/ciaa176","article-title":"Molecular and Direct Detection Tests for Treponema pallidum Subspecies pallidum: A Review of the Literature, 1964\u20132017","volume":"71","author":"Theel","year":"2020","journal-title":"Clin. Infect. Dis."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Caruso, G., Giammanco, A., Virruso, R., and Fasciana, T. (2021). Current and Future Trends in the Laboratory Diagnosis of Sexually Transmitted Infections. Int. J. Environ. Res. Public Health, 18.","DOI":"10.3390\/ijerph18031038"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"285","DOI":"10.1097\/OLQ.0000000000000126","article-title":"Evaluation of diagnostic serological results in cases of suspected primary syphilis infection","volume":"41","author":"Gratzer","year":"2014","journal-title":"Sex. Transm. Dis."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"633","DOI":"10.1097\/00007611-197105000-00030","article-title":"The VDRL slide test in 322 cases of darkfield positive primary syphilis","volume":"64","author":"Wende","year":"1971","journal-title":"South. Med. J."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1016","DOI":"10.1097\/OLQ.0b013e3181124473","article-title":"An evaluation of the relative sensitivities of the venereal disease research laboratory test and the Treponema pallidum particle agglutination test among patients diagnosed with primary syphilis","volume":"34","author":"Creegan","year":"2007","journal-title":"Sex. Transm. Dis."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"642","DOI":"10.1056\/NEJM197103252841205","article-title":"Diagnosis and treatment of syphilis","volume":"284","author":"Sparling","year":"1971","journal-title":"N. Engl. J. Med."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"817","DOI":"10.1001\/jama.1982.03320310065035","article-title":"Posttreatment serological response of biologic false-positive reactors","volume":"247","author":"Fiumara","year":"1982","journal-title":"JAMA"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"e796","DOI":"10.1111\/jdv.18934","article-title":"Epidemiological and serological characteristics of patients with late syphilis: A retrospective cohort of 76 patients","volume":"37","author":"Salle","year":"2023","journal-title":"J. Eur. Acad. Dermatol. Venereol."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1092","DOI":"10.1093\/cid\/cir671","article-title":"Predictors of serological cure and Serofast State after treatment in HIV-negative persons with early syphilis","volume":"53","author":"Wolff","year":"2011","journal-title":"Clin. Infect. Dis."},{"key":"ref_23","unstructured":"Larsen, S.A. (1999). Manual of Tests for Syphilis, American Public Health Association. [9th ed.]."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"528","DOI":"10.1097\/OLQ.0b013e318205491a","article-title":"Evaluation of an IgM\/IgG sensitive enzyme immunoassay and the utility of index values for the screening of syphilis infection in a high-risk population","volume":"38","author":"Wong","year":"2011","journal-title":"Sex. Transm. Dis."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Lieberman, N.A.P., Lin, M.J., Xie, H., Shrestha, L., Nguyen, T., Huang, M.L., Haynes, A.M., Romeis, E., Wang, Q.Q., and Zhang, R.L. (2021). Treponema pallidum genome sequencing from six continents reveals variability in vaccine candidate genes and dominance of Nichols clade strains in Madagascar. PLoS Negl. Trop. Dis., 15.","DOI":"10.1371\/journal.pntd.0010063"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"11","DOI":"10.1002\/pro.2576","article-title":"Insights into the potential function and membrane organization of the TP0435 (Tp17) lipoprotein from Treponema pallidum derived from structural and biophysical analyses","volume":"24","author":"Brautigam","year":"2015","journal-title":"Protein Sci."},{"key":"ref_27","first-page":"70","article-title":"Ceftriaxone is effective for treating patients with primary syphilis","volume":"15","author":"Janier","year":"1988","journal-title":"Sex. Transm. Dis."},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Kojima, N., Park, H., Konda, K.A., Joseph Davey, D.L., Bristow, C.C., Brown, B., Leon, S.R., Vargas, S.K., Calvo, G.M., and Caceres, C.F. (2017). The PICASSO Cohort: Baseline characteristics of a cohort of men who have sex with men and male-to-female transgender women at high risk for syphilis infection in Lima, Peru. BMC Infect. Dis., 17.","DOI":"10.1186\/s12879-017-2332-x"},{"key":"ref_29","first-page":"12A.1.1","article-title":"Isolation and laboratory maintenance of Treponema pallidum","volume":"7","author":"Lukehart","year":"2007","journal-title":"Curr. Protoc. Microbiol."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"767","DOI":"10.1007\/s10517-018-4261-0","article-title":"Immunochip for Syphilis Serodiagnostics with the Use of Extended Array of Treponema pallidum Recombinant Antigens","volume":"165","author":"Runina","year":"2018","journal-title":"Bull. Exp. Biol. Med."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"207","DOI":"10.1016\/j.pep.2005.01.016","article-title":"Protein production by auto-induction in high density shaking cultures","volume":"41","author":"Studier","year":"2005","journal-title":"Protein Expr. Purif."},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Molini, B., Fernandez, M.C., Godornes, C., Vorobieva, A., Lukehart, S.A., and Giacani, L. (2022). B-Cell Epitope Mapping of TprC and TprD Variants of Treponema pallidum Subspecies Informs Vaccine Development for Human Treponematoses. Front. Immunol., 13.","DOI":"10.3389\/fimmu.2022.862491"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"453","DOI":"10.1107\/S1744309113006246","article-title":"Purification, crystallization and preliminary X-ray analysis of TP0435 (Tp17) from the syphilis spirochete Treponema pallidum","volume":"69","author":"Brautigam","year":"2013","journal-title":"Acta Crystallogr. Sect. F Struct. Biol. Cryst. Commun."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"952","DOI":"10.4049\/jimmunol.169.2.952","article-title":"Segregation of B and T cell epitopes of Treponema pallidum repeat protein K to variable and conserved regions during experimental syphilis infection","volume":"169","author":"Morgan","year":"2002","journal-title":"J. Immunol."},{"key":"ref_35","doi-asserted-by":"crossref","unstructured":"De Lay, B.D., Cameron, T.A., De Lay, N.R., Norris, S.J., and Edmondson, D.G. (2021). Comparison of transcriptional profiles of Treponema pallidum during experimental infection of rabbits and in vitro culture: Highly similar, yet different. PLoS Pathog., 17.","DOI":"10.1371\/journal.ppat.1009949"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"1866","DOI":"10.1128\/JB.187.5.1866-1874.2005","article-title":"Transcriptome of Treponema pallidum: Gene expression profile during experimental rabbit infection","volume":"187","author":"Smajs","year":"2005","journal-title":"J. Bacteriol."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"490","DOI":"10.1128\/iai.56.2.490-498.1988","article-title":"Identification and localization of integral membrane proteins of virulent Treponema pallidum subsp. pallidum by phase partitioning with the nonionic detergent triton X-114","volume":"56","author":"Radolf","year":"1988","journal-title":"Infect. Immun."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"1973","DOI":"10.4049\/jimmunol.131.4.1973","article-title":"Humoral immune response in experimental syphilis to polypeptides of Treponema pallidum","volume":"131","author":"Hanff","year":"1983","journal-title":"J. Immunol."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"4363","DOI":"10.4049\/jimmunol.141.12.4363","article-title":"Development of cellular immunity to individual soluble antigens of Treponema pallidum during experimental syphilis","volume":"141","author":"Fohn","year":"1988","journal-title":"J. Immunol."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"1287","DOI":"10.4049\/jimmunol.129.3.1287","article-title":"Humoral immune response in human syphilis to polypeptides of Treponema pallidum","volume":"129","author":"Hanff","year":"1982","journal-title":"J. Immunol."},{"key":"ref_41","first-page":"949","article-title":"Lipoprotein-dependent and -independent immune responses to spirochetal infection","volume":"12","author":"Salazar","year":"2005","journal-title":"Clin. Diagn. Lab. Immunol."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"878","DOI":"10.1038\/nm732","article-title":"Hyporesponsiveness to vaccination with Borrelia burgdorferi OspA in humans and in TLR1- and TLR2-deficient mice","volume":"8","author":"Alexopoulou","year":"2002","journal-title":"Nat. Med."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"736","DOI":"10.1126\/science.285.5428.736","article-title":"Cell activation and apoptosis by bacterial lipoproteins through toll-like receptor-2","volume":"285","author":"Aliprantis","year":"1999","journal-title":"Science"},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"732","DOI":"10.1126\/science.285.5428.732","article-title":"Host defense mechanisms triggered by microbial lipoproteins through toll-like receptors","volume":"285","author":"Brightbill","year":"1999","journal-title":"Science"},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"2049","DOI":"10.4049\/jimmunol.163.4.2049","article-title":"Activation of human monocytic cells by Borrelia burgdorferi and Treponema pallidum is facilitated by CD14 and correlates with surface exposure of spirochetal lipoproteins","volume":"163","author":"Sellati","year":"1999","journal-title":"J. Immunol."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"913","DOI":"10.1093\/cid\/ciy558","article-title":"Performance of Treponemal Tests for the Diagnosis of Syphilis","volume":"68","author":"Park","year":"2019","journal-title":"Clin. Infect. Dis."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"10","DOI":"10.1128\/IAI.00323-19","article-title":"Evaluation of the Protective Ability of the Treponema pallidum subsp. pallidum Tp0126 OmpW Homolog in the Rabbit Model of Syphilis","volume":"87","author":"Haynes","year":"2019","journal-title":"Infect. Immun."},{"key":"ref_48","doi-asserted-by":"crossref","unstructured":"Chan, K., Nasereddin, T., Alter, L., Centurion-Lara, A., Giacani, L., and Parveen, N. (2016). Treponema pallidum Lipoprotein TP0435 Expressed in Borrelia burgdorferi Produces Multiple Surface\/Periplasmic Isoforms and mediates Adherence. Sci. Rep., 6.","DOI":"10.1038\/srep25593"},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"1807","DOI":"10.1016\/j.vaccine.2019.02.022","article-title":"Non-pathogenic Borrelia burgdorferi expressing Treponema pallidum TprK and Tp0435 antigens as a novel approach to evaluate syphilis vaccine candidates","volume":"37","author":"Parveen","year":"2019","journal-title":"Vaccine"}],"container-title":["Diagnostics"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2075-4418\/15\/11\/1443\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,9]],"date-time":"2025-10-09T17:47:22Z","timestamp":1760032042000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2075-4418\/15\/11\/1443"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,6,5]]},"references-count":49,"journal-issue":{"issue":"11","published-online":{"date-parts":[[2025,6]]}},"alternative-id":["diagnostics15111443"],"URL":"https:\/\/doi.org\/10.3390\/diagnostics15111443","relation":{},"ISSN":["2075-4418"],"issn-type":[{"type":"electronic","value":"2075-4418"}],"subject":[],"published":{"date-parts":[[2025,6,5]]}}}