Nanobodies: a new frontier in influenza virus neutralization.

Recurrent epidemics and pandemics caused by seasonal human influenza viruses result in substantial morbidity and are a significant public health burden worldwide annually. Antiviral drugs are used to treat influenza infections but have several limitations.. Therefore, monoclonal antibody therapy is an exciting and promising approach. Nanobodies, also known as single-domain antibodies, are a new class derived from heavy-chain-only antibodies found in camelids like alpacas, llamas, and camels. These antibodies neutralize influenza viruses by targeting various proteins through multiple mechanisms. For example, they can target the hemagglutinin protein to prevent its functions. By focusing on conserved epitopes, they can neutralize a variety of influenza subtypes, including seasonal flu strains and possible pandemic variants. Additionally, these antibodies can neutralize free-floating viruses in the extracellular environment, preventing them from infecting cells. They can reduce the viral load and limit the spread of the infection. Using nanobodies to neutralize influenza viruses provides numerous advantages compared to conventional antibodies. Thanks to their unique properties, nanobodies play a crucial role in fighting influenza, improving disease management, and strengthening public health responses. In this review, we summarize the role of nanobodies in influenza virus neutralization.