Dead or alive: how the immune system detects microbial viability

Curr Opin Immunol. 2019 Feb;56:60-66. doi: 10.1016/j.coi.2018.09.018. Epub 2018 Oct 24.


Immune detection of microbial viability is increasingly recognized as a potent driver of innate and adaptive immune responses. Here we describe recent mechanistic insights into the process of how the immune system discriminates between viable and non-viable microbial matter. Accumulating evidence suggests a key role for microbial RNA as a widely conserved viability associated PAMP (vita-PAMP) and a molecular signal of increased infectious threat. Toll-like receptor 8 (TLR8) has recently emerged as a critical sensor for viable bacteria, ssRNA viruses, and archaea in human antigen presenting cells (APC). We discuss the role of microbial RNA, and other potential vita-PAMPs in antimicrobial immunity and vaccine responses.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Animals
  • Apoptosis / immunology*
  • Humans
  • Immune System*
  • Immunity, Heterologous
  • Microbial Viability
  • Pathogen-Associated Molecular Pattern Molecules / immunology
  • Receptors, Pattern Recognition / metabolism
  • Signal Transduction
  • Vaccines / immunology*


  • Pathogen-Associated Molecular Pattern Molecules
  • Receptors, Pattern Recognition
  • Vaccines