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BackgroundTreponema pallidum subspecies pallidum causes systemic syphilis, exclusively infects humans in nature and can persist for decades in the absence of...

YouTube video by Monitor

YouTube video by Monitor

Treponema pallidum subspecies pallidum (T. pallidum) causes systemic syphilis, exclusively infects humans in nature and can persist for decades in the absence of treatment despite generating robust adaptive immune responses. The T. pallidumrepeat (Tpr) family of outer membrane proteins are immunogenic but have been implicated in immune evasion due to antigenic variation, indicating that Tprs are virulence factors displayed on the spirochetes surface. Long-term survival of T. pallidum is largely attributed to the sparse surface-exposed outer membrane proteins and antigenic variation exhibited by the major surface protein TprK, which undergoes phase variation. Mechanism of antigenic variation has been studied for decades; however, functions of Tprs in this extracellular pathogen have not been experimentally determined. In this study, we determined TprD and TprK location, their role in adherence and in clearance of T. pallidum by macrophages. Using our now established heterologous surrogate system and gain-in-function approach using non-adherent related spirochete, the B314 strain of Borrelia burgdorferi, we show that both TprD and TprK are surface exposed to some extent on engineered B. burgdorferi as well as on T. pallidum Nichols and SS14 strains. We further demonstrate that both proteins mediate adherence to different mammalian cells in vitro and mouse antibodies generated against TprD and TprK putative surface loops bind spirochetes and promote J774A.1 macrophages-mediated opsonophagocytosis. Thus, surface-exposed adhesins TprD and TprK of T. pallidum contribute to binding to different types of cells which likely reflect the pathogens ability to colonize different tissues, and they are also targets of opsonic antibodies.

Treponema pallidum subspecies pallidum (T. pallidum) causes systemic syphilis, exclusively infects humans in nature and can persist for decades in the absence of treatment despite generating robust adaptive immune responses. The T. pallidumrepeat (Tpr) family of outer membrane proteins are immunogenic but have been implicated in immune evasion due to antigenic variation, indicating that Tprs are virulence factors displayed on the spirochetes surface. Long-term survival of T. pallidum is largely attributed to the sparse surface-exposed outer membrane proteins and antigenic variation exhibited by the major surface protein TprK, which undergoes phase variation. Mechanism of antigenic variation has been studied for decades; however, functions of Tprs in this extracellular pathogen have not been experimentally determined. In this study, we determined TprD and TprK location, their role in adherence and in clearance of T. pallidum by macrophages. Using our now established heterologous surrogate system and gain-in-function approach using non-adherent related spirochete, the B314 strain of Borrelia burgdorferi, we show that both TprD and TprK are surface exposed to some extent on engineered B. burgdorferi as well as on T. pallidum Nichols and SS14 strains. We further demonstrate that both proteins mediate adherence to different mammalian cells in vitro and mouse antibodies generated against TprD and TprK putative surface loops bind spirochetes and promote J774A.1 macrophages-mediated opsonophagocytosis. Thus, surface-exposed adhesins TprD and TprK of T. pallidum contribute to binding to different types of cells which likely reflect the pathogens ability to colonize different tissues, and they are also targets of opsonic antibodies.

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I need to get this surgery ASAP anyone who have information regarding this please do reply, I have 525 CCT and thinnest cornea thickness is 503 with kmax of 54.6, is it safe, and how much myopia and astigmatism will be reduced after surgery? submitted by…

I've recently been diagnosed and qualified for both TPRK + CXL here in Canada through LasikMD. I've done my fair bit of research on both surgeries and wanted to ask those of you that have done the surgery how your recovery was? They have only found KC in…

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