Previously Unrecognized Nonreproducible Antibody-Probe Interactions.

Antibody-antigen (Ab-Ag) interactions are canonically described by a model that exclusively accommodates noninteraction (0) or reproducible interaction (RI) states, yet this model is inadequate to explain often-encountered nonreproducible signals. Here, by monitoring diverse experimental systems using a peptide-protein hybrid microarray, we observed that Ab-probe interactions comprise a substantial proportion of nonreproducible antibody-based results. This enabled our discovery and capacity to reliably identify nonreproducible Ab-probe interactions (NRIs), as well as our development of a powerful explanatory model ("0-NRI-RI-Hook four-state model") that is mAb concentration-dependent, regardless of specificity, which ultimately shows that both nonspecific interactions and NRIs are not predictable yet certain to happen. Our discoveries challenge the centrality of Ab-Ag interaction specificity data in serology and immunology.