Multivalent Anti-ACE2 Nanobodies Confer Broad Pan-Sarbecovirus Protection

Bakasis, A. D.; Patejak, R.; Fridy, P. C.; Jenkins, J.; Aldis, M.; Baharani, V. A.; Sriram, L.; Molloy, K. R.; Chait, B. T.; Rout, M. P.; Cross, F. R.; Bieniasz, P. D.; Hatziioannou, T.

doi:10.64898/2026.09.01.748598

bioRxiv · 10.64898/2026.09.01.748598

Multivalent Anti-ACE2 Nanobodies Confer Broad Pan-Sarbecovirus Protection

Bakasis, A. D.·Patejak, R.·Fridy, P. C.·Jenkins, J.·Aldis, M.·Baharani, V. A.·Sriram, L.·Molloy, K. R.·Chait, B. T.·Rout, M. P.·Cross, F. R.·Bieniasz, P. D.·Hatziioannou, T.

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Abstract

The continual emergence of SARS-CoV-2 variants that rapidly evade conventional spike-directed neutralizing antibodies, together with the ongoing risk of cross-species spillover and new sarbecovirus outbreaks, underscores the need to develop broadly acting, escape-resistant therapeutic agents. Here, we optimized a nanobody discovery pipeline incorporating competition-based yeast surface display assays to isolate single-chain variable heavy chain-only antibody domains (VHHs or nanobodies) that bind human ACE2 and inhibit SARS-CoV-2 entry. Dimeric VHHs, as well as bivalent and tetravalent Fc-fusion proteins exhibited markedly increased antiviral activity, blocking a broad panel of SARS-CoV-2 variants and diverse sarbecoviruses at low-nanomolar to picomolar concentrations. These agents did not affect ACE2 enzymatic function or cell surface expression. The VHH-Fc fusion proteins had favorable pharmacokinetics and conferred prophylactic protection in mouse models of both SARS-CoV-2 and SARS-CoV infection, showcasing their potential as broadly acting receptor-targeted biologics against pandemic-threat viruses.

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Bakasis, A. D., Patejak, R., Fridy, P. C., Jenkins, J., Aldis, M., Baharani, V. A., Sriram, L., Molloy, K. R., Chait, B. T., Rout, M. P., Cross, F. R., Bieniasz, P. D., Hatziioannou, T.. 2026-09-03. Multivalent Anti-ACE2 Nanobodies Confer Broad Pan-Sarbecovirus Protection. https://doi.org/10.64898/2026.09.01.748598

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