Role of nanoscale antigen organization on B-cell activation probed using DNA origami

Arraying vaccine immunogens in a multivalent form on the surface of virus-like particles is an important strategy used to enhance the efficacy of subunit vaccines. However, the impacts of antigen valency, spacing, and spatial organization on B cell triggering remain poorly understood. Here, we use DNA origami nanoparticles to create precise nanoscale organizations of a clinically-relevant HIV gp120 immunogen to systematically interrogate their impact on B cell triggering in vitro. We find that antigen dimers elicit monotonically increasing B cell receptor activation as inter-antigen spacing increases up to ~30 nm, and only 5 immunogens arrayed on the surface of a 3D particle are needed to elicit maximal B cell calcium signaling. Our results reveal design principles of viral and immunogen display that drive functional B cell responses.