A new generation of “double antibodies” has been developed which can protect against all SARS-CoV-2 variants, as well as inhibiting mutations against the antibodies.
These “bispecific” antibodies were created by the Institute for Research in Biomedicine (IRB; Bellinzona, Switzerland), which is affiliated to the Università della Svizzera italiana (USI).
While traditional antibody-based immunisation is able to offer protection against SARS-CoV-2, there is still a need to protect against variants which may achieve “vaccine escape”, as well as inhibiting mutations which give rise to resistance, as with antibiotic resistance in bacteria.
The researchers overcame these difficulties by splicing together a pair of antibodies to make a “bispecific” antibody that simultaneously targets two viral sites. The bispecific antibody treatment has proved effective in mouse models, which maintained body weight when infected with SARS-CoV-2, compared to infected controls, which lost 20-30% body weight before humane euthanisation. The paper is available on the bioRxiv preprint server.
Study author Luca Varani of USI explained: “We exploited our knowledge of the molecular structure and biochemical traits of the virus to fuse together two human antibodies, obtaining a single bispecific molecule simultaneously attacking the virus in two independent sites critical for infectivity. Supercomputing simulations allowed us to refine and validate the bispecific antibody design, which was later produced and tested in the laboratory. Although the virus can mutate and escape from the attack of a single first-generation antibody, we have shown that it cannot do so against the double action of the bispecific.
“A single injection of the bispecific antibody provides instantaneous protection against the disease in pre-clinical trials. The antibody effectively reduces viral burden in the lungs and mitigates inflammation typical of COVID-19”, said Daniel Ruzek from the Czech Academy of Sciences who led the antibody pre-clinical testing.
The effectiveness of the bispecific antibodies holds promise for human clinical trials, with the prospect of being both an effective prevention and treatment of COVID.
Source: News-Medical.Net
Journal information: Gasparo, R D., et al. (2020) Bispecific antibody prevents SARS-CoV-2 escape and protects mice from disease. bioRxiv.doi.org/10.1101/2021.01.22.427567.
