Framework for proto-immunity in open chemical reaction networks
Phys. Rev. E 114, 054306 – Published 4 November, 2026
DOI: https://doi.org/10.1103/52n3-kwdj
Abstract
We introduce a framework for immune-like protection in chemical reaction networks obeying deterministic evolution laws. We consider open networks with fixed chemostats and define proto-immunity as the capacity of such systems to preserve a prescribed minimum nonequilibrium throughput, despite the introduction of invading species and reactions. Within this setting, an invasion is harmful when added species or reactions drive the throughput below threshold. We then introduce a simple defense motif in which throughput loss increases the abundance of a defense molecule that selectively clears invaders. Three threat classes are analyzed as examples: the parasitic conversion of a functional intermediate, an invader-driven shunting of that intermediate toward waste, and the sequestration of an active species into an inactive complex. For each class, resistance is determined by the linear stability of the invader-free state, while invader persistence emerges through low-dimensional bifurcation structures. Our approach provides an analytically transparent framework that identifies dynamical ingredients by which open chemical reaction networks can preserve function and remove harmful invaders.
