Biology & Philosophy

, Volume 31, Issue 6, pp 819–837 | Cite as

Microorganisms as scaffolds of host individuality: an eco-immunity account of the holobiont

  • Lynn Chiu
  • Gérard Eberl


There is currently a great debate about whether the holobiont, i.e. a multicellular host and its residential microorganisms, constitutes a biological individual. We propose that resident microorganisms have a general and important role in the individuality of the host organism, not the holobiont. Drawing upon the Equilibrium Model of Immunity (Eberl in Nat Rev Immunol 16:524–532, 2016), we argue that microorganisms are scaffolds of immune capacities and processes that determine the constituency and persistence of the host organism. A scaffolding perspective accommodates the contingency and heterogeneity of resident microorganisms while accounting for their necessity and unifying contributions to host individuality. In our symbiotic view of life, holobionts may not be organisms or units of selection, but macroorganisms cannot persist nor function as individuals without their scaffolding microorganisms.


Holobiont Biological individuality Equilibrium Model of Immunity Biological scaffolds Immunological individuality Symbiosis 



We thank Thomas Pradeu for bringing us together during the first ERC-IDEM workshop at Bordeaux and for the multiple rounds of extremely valuable comments and discussions. We also thank the three anonymous referees for their rapid, insightful, and impressively detailed comments. Special thanks to Layal Massara, ChiaHua Lin, Richard Lauer, Scott Gilbert, Peter Godfrey-Smith, and the participants of the First Bordeaux-San Sebastian Workshop on Philosophy of Biology for their useful comments, and to Valérie Jolivel, Weijen Liu, Bi-Huei Yang, and André Ariew for encouraging discussions at various stages of this manuscript. We thank Gregory Dupuy for editorial suggestions. Part of this work was inspired by discussions with James Griesemer after ISHPSSB 2013. All mistakes and errors are exclusively our own. This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme—grant agreement No 637647—IDEM.


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© Springer Science+Business Media Dordrecht 2016

Authors and Affiliations

  1. 1.ImmunoConcEpT Lab, UMR CNRS 5164University of Bordeaux/CNRSBordeauxFrance
  2. 2.Microenvironment and Immunity Unit, INSERM U1224Institut PasteurParisFrance

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