Evaluating the Synergistic Effects of Multi-Epitope Nanobodies on BA.2.86 Variant Immune Escape.

Addressing the frequent emergence of SARS-CoV-2 mutant strains requires therapeutic approaches with innovative neutralization mechanisms. The targeting of multivalent nanobodies can enhance potency and reduce the risk of viral escape, positioning them as promising drug candidates. Here, the synergistic mechanisms of the two types of nanobodies are investigated deeply. Our research revealed that the Fu2-1-Fu2-2 system exhibited significant synergy, whereas the Sb#15-Sb#68 system demonstrated antagonism, in which entropy was the dominant contributor to antagonism. Conformational analysis further demonstrated that the presence of a monomeric nanobody influenced the flexibility of residues near other epitopes, thereby affecting the overall synergy of the systems. Moreover, we identified that changes in the hydrogen bond network and the charge of residues played a critical role in the binding between nanobodies and spike. We hope this study will provide novel insights into the development of multivalent nanobody combinations.