A synthetic lymph node containing inactivated Treponema pallidum cells elicits strong, antigen-specific humoral and cellular immune responses in mice

Authors

  • Lola V. Stamm,

    Corresponding author
    1. The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
    • Correspondence

      Lola V. Stamm, Infectious Diseases Program, Department of Epidemiology, Gillings School of Global Public Health, Michael Hooker Research Building, S. Columbia St., The University of North Carolina at Chapel Hill, NC 27599-7435, USA.

      Tel.: +919 966 3809

      fax: +919 966 0584

      e-mail: lstamm@email.unc.edu

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  • Rebecca L. Drapp

    1. The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
    Current affiliation:
    1. Rebecca L. Drapp, North Carolina State University College of Veterinary Medicine, Raleigh, NC, USA
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  • In this interesting study by Stamm and Drapp the authors demonstrate that synthetic lymph nodes implanted into mice that carried Treponema pallidum antigen induce both strong humoral and cellular immune responses. Animal models for studying syphilis are difficult to work with and are limited. This study suggests that the mouse model has the potential to be employed as a tool for investigating immune responses to Treponema pallidum.

Abstract

The goal of this study was to investigate the use of a synthetic lymph node (SLN) for delivery of Treponema pallidum (Tp) antigens. Immune responses of C57BL/6 mice were analyzed at 4, 8, and 12 weeks after SLN implantation. Group 1 mice received SLN with no antigen; Group 2, SLN with formalin-inactivated Tp (f-Tp); and Group 3, SLN with f-Tp plus a CpG oligodeoxynucleotide. When tested by ELISA, sera from Group 2 and Group 3 mice showed stronger IgG antibody reactivity than sera from Group 1 mice to sonicates of f-Tp or untreated Tp, but not to sonicate of normal rabbit testicular extract at all times. The IgG1 level was higher than IgG2c level for Group 2 mice at all times and for Group 3 mice at 4 and 8 weeks. IgG1 and IgG2c levels were nearly equivalent for Group 3 mice at 12 weeks. Immunoblotting showed that IgG from Group 2 and Group 3 mice recognized several Tp proteins at all times. Supernatants of splenocytes from Group 2 and Group 3 mice contained significantly more IFNγ than those from Group 1 mice after stimulation with f-Tp at all times. A significant level of IL-4 was not detected in any supernatants. These data show that strong humoral and cellular immune responses to Tp can be elicited via a SLN.

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