Stochastic and Quantum Perspectives on Teleost Immunity: Linking Immunogenetics, Structure, and Biophysics

Teleost fishes possess highly diverse, lineage-specific pattern-recognition receptor (PRR) repertoires shaped by teleost-specific whole-genome duplication (3R-WGD), subsequent duplication, differential retention, functional divergence, and gene loss. Toll-like, RIG-I-like, and NOD-like receptor families show lineage-specific expansion and, in some cases, adaptive sequence evolution, particularly in regions implicated in ligand recognition. Separately, hydrogen tunneling is supported in specific enzyme reactions, while radical-pair chemistry provides a bounded mechanistic precedent rather than evidence for teleost immune function. This review examines whether teleost PRR diversification creates concrete, testable opportunities for investigating analogous biophysical mechanisms, without assuming that receptor diversity or environmental sensitivity entails non-classical effects. A five-level evidence hierarchy is applied: direct teleost evidence, evidence from other systems, indirect teleost evidence, testable hypothesis, and unsupported or contradicted claim. No direct evidence was identified for a functionally consequential quantum-biological mechanism in teleost immune recognition or signaling. However, increasing genomic, structural, transcriptomic, single-cell, and functional-genomic resolution provides a tractable framework for testing such possibilities. Sequence and structural divergence among PRR paralogs can be evaluated using structure prediction, molecular dynamics, and, where chemically justified, quantum-chemical or QM/MM methods, with uncertainty assessed across stages and experimental validation through ligand binding, signaling, and environmental-response phenotypes. The NADPH-to-flavin hydride-transfer step in an immune effector oxidase is proposed as a chemically defined candidate, not an established teleost tunneling mechanism. Quantum mechanisms therefore remain hypotheses rather than established features of teleost immunity. A falsifiable research roadmap is proposed linking receptor evolution to structure-function relationships, signaling diversity, redox processes, and candidate quantum-sensitive molecular events.