By Julie Steenhuysen and Nancy Lapid

Feb 21 (Reuters) - A newly discovered bat coronavirus uses the same cell-surface protein to gain entry into human cells as the SARS-CoV-2 virus that causes COVID-19, raising the possibility that it could someday spread to humans, Chinese researchers have reported.

The virus does not enter human cells as readily as SARS-CoV-2 does, the Chinese researchers reported in the journal Cell, noting some of its limitations.

The scientists said that like SARS-CoV-2, the bat virus HKU5-CoV-2 contains a feature known as the furin cleavage site that helps it to enter cells via the ACE2 receptor protein on cell surfaces.

In lab experiments, HKU5-CoV-2 infected human cells with high ACE2 levels in test tubes and in models of human intestines and airways.

In further experiments, the researchers identified monoclonal antibodies and antiviral drugs that target the bat virus.

Bloomberg, which reported on the study earlier on Friday, said the paper identifying the bat virus had moved shares of COVID vaccine makers. Pfizer PFE.N shares closed up 1.5% on Friday, Moderna MRNA.O climbed 5.3% and Novavax NVAX.O was up about 1% on a down day for the broader market.

Asked about concerns raised by the report of another pandemic resulting from this new virus, Dr. Michael Osterholm, an infectious disease expert at the University of Minnesota, called the reaction to the study "overblown."

He said there is a lot of immunity in the population to similar SARS viruses compared with 2019, which may reduce the pandemic risk.

The study itself noted that the virus has significantly less binding affinity to human ACE2 than SARS-CoV-2, and other suboptimal factors for human adaptation suggest the "risk of emergence in human populations should not be exaggerated."

(Reporting by Julie Steenhuysen and Nancy Lapid; Editing by Caroline Humer and Bill Berkrot)

((Nancy.Lapid@thomsonreuters.com;))