SCIENCE: New COVID-like virus in Russian bats shows resistance to vaccine antibodies

A new coro­n­avirus dis­cov­ered in Russ­ian bats has prompt­ed sci­en­tists to call for urgent efforts to make a vac­cine avail­able. Oth­er­wise, it warns that anoth­er pan­dem­ic could be trig­gered by a dead­ly ani­mal virus infect­ing humans.

Sim­i­lar to SARS-CoV­‑2, a new res­pi­ra­to­ry virus found among bats called Khosta‑2 is coat­ed with a spike pro­tein and can use the same entry route to infect human cells. increase.

Even more prob­lem­at­ic is the appar­ent resis­tance to mon­o­clon­al anti­bod­ies and sera induced in COVID-19 vaccinees.

This means that this new res­pi­ra­to­ry virus can­not be neu­tral­ized by exist­ing drugs.

Even anti­bod­ies devel­oped from omi­cron mutants were inef­fec­tive against bat virus­es, even though they are in the same group of acute res­pi­ra­to­ry coro­n­avirus­es (sar­be­covirus­es).

“These results high­light the urgent need to devel­op new sar­be­covirus vac­cines with broad­er pro­tec­tion,” the authors wrote.

When Russ­ian researchers first encoun­tered Khosta‑2 and anoth­er bat virus, Khosta‑1, in 2020, nei­ther pathogen seemed par­tic­u­lar­ly dangerous.

Nei­ther were close­ly relat­ed to SARS-CoV­‑2. The gene actu­al­ly came from a dif­fer­ent lin­eage that lacked some of the genes researchers thought were nec­es­sary to antag­o­nize the human immune system.

But upon clos­er inspec­tion, experts have con­firmed that Khosta‑2 has some wor­ri­some features.

In the lab, the bat pathogen was found to infect tis­sues in much the same way as SARS-CoV­‑2, uti­liz­ing the angiotensin-con­vert­ing enzyme 2 (ACE2) recep­tor on human liv­er cells. Also, the recep­tor-bind­ing domain of its spike pro­tein exhib­it­ed com­plete resis­tance to mon­o­clon­al anti­bod­ies induced by the COVID-19 vaccine.

Virol­o­gist Michael Letko of Wash­ing­ton State Uni­ver­si­ty said, “Genet­i­cal­ly, this strange Russ­ian virus was sim­i­lar to oth­er virus­es found in oth­er parts of the world. But SARS-CoV­‑2 has It did­n’t look like it, so no one thought this virus was real­ly exciting.”

“How­ev­er, upon fur­ther study, we were very sur­prised to find that they infect human cells. It’s going to change a lit­tle bit.”

Khosta‑2 was dis­cov­ered in the Sochi Nation­al Park, Rus­sia, among the small bat (Rhi­nolo­phus hip­posideros), which is also found in Europe and North Africa.

It is not yet clear whether these bat-infect­ing virus­es will infect humans in the real world, but ear­ly results in the lab sug­gest it is cer­tain­ly possible.

If the Khosta‑2 virus infects oth­er coro­n­avirus­es, it is even pos­si­ble that the two virus­es com­bine to form an entire­ly new virus.

In the lab, Khosta‑1 could not infect human cells on its own, but when the pro­tein-eat­ing enzyme was arti­fi­cial­ly added, the virus was sud­den­ly able to enter human cells through anoth­er gateway.

“These find­ings sug­gest that some coro­n­avirus­es infect human cells through a cur­rent­ly unknown recep­tor,” the authors write.

“Since Salve­dovirus­es have been shown to co-cir­cu­late in bats, dif­fer­ences in how these recep­tors are used among close­ly relat­ed virus­es may con­tribute to their per­sis­tence in reser­voir host pop­u­la­tions. It could even be an evo­lu­tion­ary strategy.”

obvi­ous­ly bad. Cur­rent coro­n­avirus vac­cines, which pri­mar­i­ly tar­get the ACE2 recep­tor, may not be able to pre­vent infec­tion if this viral reser­voir spreads to humans.

The lab found that replac­ing the recep­tor-bind­ing domain of the SARS-CoV­‑2 virus with a Khos­ta-2-bind­ing domain made the sera of vac­ci­nees less effec­tive at neu­tral­iz­ing the pseudovirus.

“There are groups now try­ing to cre­ate a vac­cine that not only pro­tects against the next SARS‑2 vari­ant, but against Salvec virus in gen­er­al,” says Letko.

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