MyD88 Shapes Vaccine Immunity by Extrinsically Regulating Survival of CD4+ T Cells during the Contraction Phase

Date
2016-08-19
Authors
Wang, Huafeng
Li, Mengyi
Hung, Chiung-Yu
Sinha, Meenal
Lee, Linda M.
Wiesner, Darin L.
LeBert, Vanessa
Lerksuthirat, Tassanee
Galles, Kevin
Suresh, Marulasiddappa
Journal Title
Journal ISSN
Volume Title
Publisher
Public Library of Science
Abstract

Soaring rates of systemic fungal infections worldwide underscore the need for vaccine prevention. An understanding of the elements that promote vaccine immunity is essential. We previously reported that Th17 cells are required for vaccine immunity to the systemic dimorphic fungi of North America, and that Card9 and MyD88 signaling are required for the development of protective Th17 cells. Herein, we investigated where, when and how MyD88 regulates T cell development. We uncovered a novel mechanism in which MyD88 extrinsically regulates the survival of activated T cells during the contraction phase and in the absence of inflammation, but is dispensable for the expansion and differentiation of the cells. The poor survival of activated T cells in Myd88-/- mice is linked to increased caspase3-mediated apoptosis, but not to Fas- or Bim-dependent apoptotic pathways, nor to reduced expression of the anti-apoptotic molecules Bcl-2 or Bcl-xL. Moreover, TLR3, 7, and/or 9, but not TLR2 or 4, also were required extrinsically for MyD88-dependent Th17 cell responses and vaccine immunity. Similar MyD88 requirements governed the survival of virus primed T cells. Our data identify unappreciated new requirements for eliciting adaptive immunity and have implications for designing vaccines.

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Citation
Wang, H., Li, M., Hung, C. Y., Sinha, M., Lee, L. M., Wiesner, D. L., . . . Wüthrich, M. (2016). MyD88 Shapes Vaccine Immunity by Extrinsically Regulating Survival of CD4+ T Cells during the Contraction Phase. PLOS Pathogens, 12(8), e1005787. doi:10.1371/journal.ppat.1005787
Department
Molecular Microbiology and Immunology