Prama Ghosh, Amity University Kolkata
The utilization of antibodies to battle human illness goes back to the 1890s and it is in practice even today. The blood plasma of patients who have recovered from COVID-19 contains antibodies against the SARS-CoV-2 virus which is called plasma therapy and used as a treatment for people with coronavirus infection. Inspired by this success progress is made to help antiviral responses by designing human antibodies to upgrade their antiviral movement.
The structural components of antibodies are the Fab domain which is a variable antigen-binding region and the Fc domain which engages different receptors called Fc receptors. IgG, a type of antibody engages a subfamily of Fc receptors called the FcγRs. Fc engineering in which the Fc domain can be modified to selectively enhance or reduce their interaction with different FcγRs can be used to target tumour cells and lead to the development of antibody drugs to treat cancer.
Upon replacing mouse FcγR with human FcγR, anti-influenza antibodies were observed which could provide an enhanced antiviral therapy. It was found that, compared with wild-type anti-flu IgG that had a non-engineered Fc domain, the engineered antibody has an enhanced FcγRIIa binding that induced greater maturation of antigen-presenting cells.
Since the influenza model targets the lung similar to SARS-CoV-2, the above approach is considered safe in the treatment of COVID – 19. The FcγRIIa-enhanced antibody in the case of the influenza antibody did not result in higher than normal inflammation or other evidence of antibody-dependent enhancement, such as an increase in viral infectivity.
Although the process is still unclear in the case of COVID – 19, Fc-domain engineering for antiviral therapy is a promising avenue to pursue which will lead to better treatments for both influenza and COVID – 19 viruses.
Also read: A new vaccine strategy for infectious diseases treatment
Reference: Engineered antibodies to combat viral threats Xiaojie Yu & Mark S. Cragg, https://doi.org/10.1038/d41586-020-03196-2
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