In a Kenyan laboratory, researchers tested a synthetic piece of a bat virus against human cell receptors and found it could bind to a protein linked to cancer growth.
The discovery centers on a virus from East African horseshoe bats, specifically the Cardioderma cor coronavirus strain KY43, which scientists identified as capable of using the human protein CEACAM6 as an entry point into cells. This receptor is known to be over-expressed in various human cancers and can contribute to treatment resistance, raising concerns about potential dual threats if the virus were to jump to humans.
The research, published in Nature and led by an international team including scientists from the University of York, the University of Cambridge, the Pirbright Institute, the KEMRI-Wellcome Trust Research Programme, and the National Museums of Kenya, avoided working with live virus. Instead, the team used genetic sequences from public databases to synthesize spike proteins from 27 different bat coronaviruses and screened them against a library of human receptors.
This approach allowed them to identify CEACAM6 as a functional receptor for this alphacoronavirus without the need to handle infectious material, a method praised for its safety and efficiency. Dr Giulia Gallo, the study’s lead author, emphasized that they detected this receptor interaction before any evidence of spillover into human populations, noting field data from Kenya shows no current human infection despite the virus’s capability.
The findings challenge previous assumptions that alphacoronaviruses rely on only one or two host receptors, suggesting instead a broader range of potential entry mechanisms. Dr Dalan Bailey of the Pirbright Institute stated that prior to this study, it was believed these viruses used just one of two possible receptors, with variation only in host species, but now it appears they may employ a much wider variety of strategies to infect cells.
Stephen Graham, a professor at the University of Cambridge, compared viral spike proteins to keys fitting into locks, noting that although one such “lock” has now been identified for alphacoronaviruses, the scientific challenge remains to discover how many others exist. The team highlighted that their work was made possible through collaboration between UK and Kenyan institutions, supported largely by funding from the UK’s Biotechnology and Biological Sciences Research Council.
Ethical approval for the use of human serum samples was obtained from the Kenya Medical Research Institute’s Scientific and Ethics Review Unit, with individual consent obtained from all donors prior to sample collection, underscoring the study’s adherence to local and international research standards.
The identification of this viral entry mechanism does not equate to an imminent threat, but it does highlight a previously unknown pathway that zoonotic viruses might use to cross into humans. Experts stress that understanding such mechanisms in advance of spillover events is critical for pandemic preparedness, particularly given the role of bats as reservoirs for diverse viral families.
By revealing that alphacoronaviruses can exploit receptors beyond the traditionally recognized ones, the study opens new avenues for monitoring viral evolution and assessing risk. It similarly underscores the value of using synthetic biology and genomic surveillance to study dangerous pathogens without requiring live cultures, a strategy that could become more common in virology research.
What does the virus’s ability to bind to CEACAM6 mean for human health?
While the virus can bind to this human receptor in lab settings, there is currently no evidence it has infected people. CEACAM6’s association with cancer growth and chemotherapy resistance means that if spillover were to occur, it could complicate health outcomes, but this remains speculative without actual human cases.
How did researchers study the virus without using live samples?
They synthesized spike proteins from genetic sequences obtained from public databases and tested their ability to bind to human receptors, avoiding the need to cultivate or handle infectious virus.
Why is this discovery important for predicting future outbreaks?
It shows that alphacoronaviruses may use a wider variety of receptors to enter cells than previously thought, which improves scientists’ ability to anticipate and monitor potential zoonotic threats before they emerge in human populations.