Bananas could be the ultimate defense against the flu and all coronaviruses

A potential breakthrough in flu treatment emerged in January, 2020, with the publication of a paper detailing a therapy that could target all known flu strains. Just a week later, the first confirmed U.S. case of SARS-CoV-2 shifted global attention.

The unfolding pandemic overshadowed medical research, including a promising effort by scientists who had been developing a similar approach for coronaviruses.

David Markovitz, M.D., a professor at the University of Michigan Medical School, revealed that the team initially focused on Middle Eastern Respiratory Syndrome (MERS). The virus, with a staggering 35% mortality rate, had caused a deadly outbreak in 2015, leading to 858 confirmed deaths. At the time, researchers feared MERS could spark a larger crisis.

Their latest findings, published in Cell Reports Medicine, highlight the potential of a therapy known as H84T-BanLec. The study confirmed its effectiveness against all coronaviruses that infect humans, including MERS, SARS, and SARS-CoV-2. Even the highly transmissible Omicron variant fell within its reach.

Markovitz collaborated with Peter Hinterdorfer, Ph.D., from Johannes Kepler University, and Kwok-Yung Yuen, MBBS, M.D., from the University of Hong Kong.

Jasper Fuk-Woo Chan, M.D., also from the University of Hong Kong, served as the paper’s lead author. Together, they tested the therapy across multiple models to assess its effectiveness.

As the COVID-19 pandemic unfolded, the team quickly adapted their research. “We discovered it was effective against every type of coronavirus, in both lab tests and animal models,” Markovitz said. “Whether administered systemically or through the nose, whether used early in illness or as a preventative, it worked.”

The key to H84T-BanLec lies in lectins, a type of protein found in bananas. These proteins bind to carbohydrates, and H84T-BanLec specifically targets high-mannose glycans—structures present on viral surfaces but rare on healthy human cells. This unique binding mechanism stops viruses from entering cells, halting the spread of infection.

Using sophisticated tools like atomic force microscopy, the research team confirmed that H84T-BanLec forms multiple strong bonds with the spike protein of coronaviruses. Markovitz explained that these bonds likely make it difficult for the virus to develop resistance to the therapy.

Lectins, despite their antiviral potential, have typically been avoided in therapeutic research because they can trigger harmful immune responses. However, H84T-BanLec has been modified to avoid this issue, and it showed no harmful side effects in animal models.

While there are existing treatments for COVID-19, such as remdesivir, Paxlovid, and monoclonal antibodies, they come with various limitations. Some have side effects, and many have become less effective as SARS-CoV-2 continues to evolve into new variants.

H84T-BanLec stands out because it has shown effectiveness against all tested variants of the virus and even against different strains of influenza.

The research team is hopeful that H84T-BanLec can eventually be tested in humans, a critical step in bringing this therapy to wider use. They envision it as a nasal spray or drops that could be used to prevent or treat infections during both seasonal and pandemic outbreaks of respiratory viruses.

The potential applications of H84T-BanLec may even extend beyond viruses. Because cancer cells also display high-mannose glycans on their surfaces, the researchers hope to explore whether the therapy could be adapted to target certain cancers as well.

The ability of H84T-BanLec to bind to a wide range of coronaviruses and flu strains gives it a unique edge in fighting future pandemics. While current therapies lose effectiveness as viruses evolve, this therapy’s method of targeting the virus’s surface proteins might help maintain its efficacy.

In the wake of COVID-19, many treatments have been developed, but the emergence of new variants has complicated the fight against the virus. Having a therapy like H84T-BanLec, which works across a range of virus types, could provide a more reliable tool for battling not only COVID-19 but also future outbreaks of coronaviruses and flu.

The hope now is to bring this therapy from the lab and animal models to clinical trials in humans. If successful, it could revolutionize how respiratory infections are treated, offering a new line of defense against seasonal flu, coronavirus pandemics, and even cancer.

Additional authors include Yoo Jin Oh, Shuofeng Yuan , Hin Chu , Man-Lung Yeung , Daniel Canena , Chris Chung-Sing Chan, Vincent Kwok-Man Poon, Chris ChunYiu Chan, Anna Jinxia Zhang, Jian-Piao Cai , Zi-Wei Ye , Lei Wen, Terrence Tsz-Tai Yuen, Kenn Ka-Heng Chik, Huiping Shuai, Yixin Wang, Yuxin Hou, Cuiting Luo, WanMui Chan, Zhenzhi Qin, Ko-Yung Sit, Wing-Kuk Au, Maureen Legendre, Rong Zhu, Lisa Hain , Hannah Seferovic, Robert Tampé, Kelvin Kai-Wang To, Kwok-Hung Chan, Dafydd Gareth Thomas, Miriam Klausberger, Cheng Xu , James J. Moon, Johannes Stadlmann, Josef M. Penninger, and Chris Oostenbrink. Thomas, Xu, Moon and Legendre are all from the University of Michigan.

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