Coronavirus: Chinese scientists say their inhaled antibody treatment can conquer Omicron strains
- Chongqing Medical University team isolated 58G6, a potent neutralising monoclonal antibody, from recovered Covid-19 patients and tested it against virus
- Study leader says the inhaled antibodies ‘have a strong application for the control of current and possible future mutant strains of Omicron’
Scientists from Chongqing Medical University isolated 58G6, a potent neutralising monoclonal antibody, from recovered Covid-19 patients last year and tested it against the original Sars-CoV-2 strain and the Alpha and Beta variants, which are no longer prevalent.
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After finding that the Omicron variant showed a strong ability to dodge immunity from past infection and vaccination because of structural change to its spike protein, the team further looked at the ability of 58G6 to block infection with pseudotyped, or genetically engineered, Delta and Omicron variants.
The mAb showed it was capable of binding with the Delta variant but that dropped when tested against the BA.1 and BA.2 strains of the Omicron variant, although it retained some capability.
Researchers from the Wuhan Institute of Virology changed the method of administering the mAb – from intraperitoneally, or into the abdomen, to nasal delivery with swabs – and found a very low dose of 58G6 could efficiently prevent the Omicron variant replicating in the lungs of hamsters.
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The study, led by Huang Ailong, a professor at Chongqing Medical University, was published in the peer-reviewed journal Signal Transduction and Targeted Therapy last month.
“We designed the antibody treatment to be administered via nasal spray to work better,” Huang told the Chinese state-owned Science and Technology Daily, while pointing out that the Omicron variant was mainly found in upper respiratory tract infections.
“We believe that antibodies administered by inhalation have a strong application for the control of current and possible future mutant strains of Omicron,” Huang said.
All currently approved antibody treatments must be administered by intravenous injection, requiring a high dose to ensure efficacy and they must be delivered in a medical environment.
“These advantages may overcome the efficacy limitation of currently approved neutralising antibodies that can be administered only by intravenous injection. In general, 58G6 is a promising prophylactic and therapeutic candidate against current circulating variants of concern, and even future emerging mutants,” the authors wrote.
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Despite its effectiveness as an antibody treatment, it could be undermined by pathogen mutations.
Currently available antibody treatments for Covid-19 are based on the spike protein of Sars-CoV-2, the virus that causes Covid-19. The fast evolution of the virus with continuous mutations of the spike protein has resulted in it evading immunity.
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“A number of neutralising antibodies developed by research institutes around the world will lose effectiveness with each mutation of Sars-CoV-2, especially after Omicron, which has more mutation sites,” Jin Aishun, a researcher with Chongqing Medical School who took part in the study, told Science and Technology Daily.
“We are very fortunate that the 58G6 neutralising antibody we have screened still maintains effective neutralising activity,” she said, referring to the process of blocking infection.
The treatment, now having completed preclinical studies, has been filed with China’s drug regulator for permission to go to clinical trials.
