Novel monoclonal antibodies show promise in preventing severe mpox disease
August 26, 2025
The discovery of three potent monoclonal antibodies against mpox by researchers at the Icahn School of Medicine at Mount Sinai offers a breakthrough in combating a virus that still lacks effective treatment. Targeting the highly conserved A35 viral protein, these antibodies not only blocked mpox spread in vitro but also protected rodents from severe disease and death. Importantly, people recovering from mpox consistently carried these antibodies, linking them to milder illness and no hospitalization. While clinical trials are still needed, this research highlights the potential for next-generation antibody therapies that could transform mpox treatment and strengthen defenses against orthopoxviruses.
The global mpox outbreak, which began in 2022 and has twice been declared a public health emergency of international concern, continues to expose the urgent need for effective treatments. Current therapies, including leading drug candidates, have failed to show efficacy in human trials, leaving patients vulnerable to a painful, sometimes deadly disease that spreads through close contact. A promising new study from the Icahn School of Medicine at Mount Sinai may finally signal a turning point.
Researchers identified three monoclonal antibodies from a patient previously infected with mpox that target the viral protein A35. Laboratory experiments showed these antibodies could block viral spread, while animal studies demonstrated protection from severe illness and complete prevention of death. Even more compelling, people recovering from mpox consistently produced antibodies against the same viral epitope, with higher antibody levels correlating to milder symptoms and avoidance of hospitalization.
The structural analysis provided the first crystal structure of a human antibody bound to an mpox protein, offering a detailed blueprint of viral vulnerability. Because the targeted region is conserved across orthopoxviruses and the broader poxvirus family, these antibodies may resist viral escape mutations and hold promise as durable therapies.
Though the findings are still in the preclinical stage, the implications are profound. These antibodies could be developed into preventive or therapeutic drugs, filling a critical gap in orthopoxvirus treatment options. With patents secured, the Mount Sinai team plans to advance testing into safety and efficacy studies, while leveraging structural insights to guide broader immune-response research.
This breakthrough demonstrates how immunological precision can reshape epidemic response. If proven effective in humans, these antibodies could not only provide life-saving treatment for mpox but also enhance preparedness against future poxvirus threats.