{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,29]],"date-time":"2026-10-29T23:06:31Z","timestamp":1793315191700,"version":"4.5.0"},"reference-count":22,"publisher":"Springer Science and Business Media LLC","issue":"1","license":[{"start":{"date-parts":[[2026,2,24]],"date-time":"2026-02-24T00:00:00Z","timestamp":1771891200000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"},{"start":{"date-parts":[[2026,3,30]],"date-time":"2026-03-30T00:00:00Z","timestamp":1774828800000},"content-version":"vor","delay-in-days":34,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"}],"funder":[{"name":"the National Institute of Virology and Bacteriology","award":["Programme EXCELES, Project ID No. LX22NPO5103,"],"award-info":[{"award-number":["Programme EXCELES, Project ID No. LX22NPO5103,"]}],"id":[{"id":"https:\/\/ror.org\/04xrjem68","id-type":"ROR","asserted-by":"crossref"}]},{"DOI":"10.13039\/501100001824","name":"the Czech Science Foundation","doi-asserted-by":"crossref","award":["Grant No. 23-07021"],"award-info":[{"award-number":["Grant No. 23-07021"]}],"id":[{"id":"10.13039\/501100001824","id-type":"DOI","asserted-by":"crossref"}]},{"DOI":"10.13039\/100000002","name":"the U.S. National Institutes of Health","doi-asserted-by":"crossref","award":["U19AI144177"],"award-info":[{"award-number":["U19AI144177"]}],"id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"crossref"}]}],"content-domain":{"domain":["link.springer.com"],"crossmark-restriction":false},"short-container-title":["BMC Microbiol"],"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>\n                      <jats:italic>Treponema pallidum<\/jats:italic>\n                      subsp.\n                      <jats:italic>pallidum<\/jats:italic>\n                      (\n                      <jats:italic>T. pallidum<\/jats:italic>\n                      ), the etiological agent of syphilis, was first isolated from infected humans in the early 20th century and, for decades, could only be propagated in laboratory rabbits. In 2018, a reproducible in vitro cultivation system was established using rabbit epithelial Sf1Ep cells and a complex culture medium, allowing stable growth of\n                      <jats:italic>T. pallidum<\/jats:italic>\n                      . While in vitro cultivation has revolutionized\n                      <jats:italic>T. pallidum<\/jats:italic>\n                      research, further humanization of this system is necessary to study host\u2013pathogen interactions.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      We evaluated three human foreskin fibroblast cell lines (HFF1, HFFC, and MoNa) for their ability to support in vitro growth of\n                      <jats:italic>T. pallidum<\/jats:italic>\n                      as an alternative to rabbit Sf1Ep cells. All human cell lines displayed typical fibroblast morphology and showed growth rates comparable to or slower than Sf1Ep cells, a feature favorable for treponemal propagation. Eight available\n                      <jats:italic>T. pallidum<\/jats:italic>\n                      strains representing the Nichols-like (DAL-1, Madras, London, Haiti B) and the SS14-like clusters (Mexico A, SS14, Grady, Philadelphia 1) sustained growth on human fibroblast cells for ten weeks. Notably, DAL-1 cultures have been continuously maintained on human fibroblasts for over one year. Cultivation on human fibroblasts resulted in slower overall growth of\n                      <jats:italic>T. pallidum<\/jats:italic>\n                      compared to rabbit cells. Nevertheless, Nichols-like strains retained their higher replication rates relative to SS14-like strains, consistent with observations from rabbit-based systems.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>\n                      Human foreskin fibroblasts can serve as effective cells for support of\n                      <jats:italic>T. pallidum<\/jats:italic>\n                      growth in vitro. This approach represents a step toward humanized culture conditions, enabling further investigation of the pathogenesis of syphilis.\n                    <\/jats:p>\n                  <\/jats:sec>","DOI":"10.1186\/s12866-026-04856-5","type":"journal-article","created":{"date-parts":[[2026,2,24]],"date-time":"2026-02-24T04:18:09Z","timestamp":1771906689000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":7,"title":["First human cell-based cultivation system for the syphilis spirochete Treponema pallidum"],"prefix":"10.1186","volume":"26","author":[{"given":"Juraj","family":"Bos\u00e1k","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mat\u011bj","family":"Hrala","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Petra","family":"Posp\u00ed\u0161ilov\u00e1","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Michaela","family":"Bosakova","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"David","family":"\u0160majs","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"297","published-online":{"date-parts":[[2026,2,24]]},"reference":[{"key":"4856_CR1","doi-asserted-by":"publisher","first-page":"e0143304","DOI":"10.1371\/JOURNAL.PONE.0143304","volume":"10","author":"L Newman","year":"2015","unstructured":"Newman L, Rowley J, Hoorn S, Vander, Wijesooriya NS, Unemo M, Low N, et al. Global estimates of the prevalence and incidence of four curable sexually transmitted infections in 2012 based on systematic review and global reporting. PLoS ONE. 2015;10:e0143304. https:\/\/doi.org\/10.1371\/JOURNAL.PONE.0143304.","journal-title":"PLoS ONE"},{"key":"4856_CR2","doi-asserted-by":"publisher","first-page":"e17073","DOI":"10.1038\/NRDP.2017.73","volume":"3","author":"RW Peeling","year":"2017","unstructured":"Peeling RW, Mabey D, Kamb ML, Chen XS, Radolf JD, Benzaken AS, Syphilis. Nat Rev Dis Prim. 2017;3:e17073. https:\/\/doi.org\/10.1038\/NRDP.2017.73.","journal-title":"Nat Rev Dis Prim"},{"key":"4856_CR3","unstructured":"WHO. Global Sexually Transmitted Infections Programme [Online]. 2024. Available at: https:\/\/www.who.int\/teams\/global-hiv-hepatitis-and-stis-programmes\/stis\/strategic-information."},{"key":"4856_CR4","doi-asserted-by":"publisher","first-page":"390","DOI":"10.1016\/0076-6879(94)36029-4","volume":"236","author":"DL Cox","year":"1994","unstructured":"Cox DL. Culture of Treponema pallidum. Methods Enzymol. 1994;236:390\u2013405. https:\/\/doi.org\/10.1016\/0076-6879(94)36029-4.","journal-title":"Methods Enzymol"},{"key":"4856_CR5","doi-asserted-by":"publisher","first-page":"908","DOI":"10.1128\/iai.32.2.908-915.1981","volume":"32","author":"AH Fieldsteel","year":"1981","unstructured":"Fieldsteel AH, Cox DL, Moeckli RA. Cultivation of virulent Treponema pallidum in tissue culture. Infect Immun. 1981;32:908\u201315. https:\/\/doi.org\/10.1128\/iai.32.2.908-915.1981.","journal-title":"Infect Immun"},{"key":"4856_CR6","doi-asserted-by":"publisher","unstructured":"Edmondson DG, Hu B, Norris SJ. 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