Center for Theoretical Biological Physics
Chemical and Biomolecular Engineering
Dean of Engineering
Dean of Natural Sciences
Physics & Astronomy
Physics Department, McGill University
“Immune Recognition, Antagonism and Phenotypic Spandrel”
Tuesday, September 27, 2016
to 1:30 PM
1060 A/B BioScience Research Collaborative
6500 Main St.
Houston, Texas, USA
Abstract: In silico evolution can be used to predict design features of networks. The important problem of early immune response, to discriminate between self from not self, is considered. Rounds of evolution with different constraints uncover elaborations of the same principle, that we name “adaptive sorting”. Corresponding networks are identified in current models of immune recognition. Adaptive sorting is never performed without detrimental ligand antagonism: a "dog in the manger" effect in which ligands unable to trigger response prevent agonists to do so, that we have observed experimentally in the T cell context. Inspired by the famous discussion by Gould and Lewontin, we establish that antagonism actually is a phenotypic spandrel: a phenotype existing as a necessary by-product of another phenotype (here specific ligand discrimination). Phenotypic spandrels reveal the internal feedbacks and constraints structuring response in signaling pathways, in very similar way to symmetries structuring physical laws.