COVID-19: New Research May Improve Plasma Therapy Significantly

Some countries in the world have been using convalescent blood plasma therapy to treat critically ill COVID-19 patients. The process entails blood plasma, collected from patients recovering from the disease, being injected into those who are critical. The antibodies in the blood plasma of the recovering or convalescent patients can neutralise the virus in those who are suffering.

However, this form of therapy is facing apprehensions. Firstly, it lacks evidence of wide-scale benefit from large randomised studies. Moreover, placebo control studies are also lacking.

A new finding, which has been published in the science journal Nature, however, has brought forth some encouragement. A team of researchers have isolated an antibody named EY6A from recovering patients. They also found a new and highly conserved site of the SARS-CoV-2 virus, one which that causes COVID-19. The isolated antibody can bind at this conserved site and neutralise the virus.

This finding has two-fold values. It has found new targets which antibodies can bind to and neutralise the virus. When we have limited sites of the virus that can be latched onto by an antibody, then there might be a situation where some antibodies may not bind to those specific targets, lessening chances of the neutralisation of the virus. Secondly, finding new antibodies is also encouraging. The greater variety of the neutralising antibodies there are, the more chances we have of restricting the novel coronavirus.

The benefits also have implications for viral mutations. Mutations may give the virus the ability to change its structure and evade some of the antibodies that previously could neutralise it, as a result. A greater variety of virus sites and antibodies could prove to be effective in overpowering the mutational changes of the virus.

In convalescent blood plasma therapy, antibodies are collected from recovering patients. In this context, convalescence means the period between the patient testing negative and the time to taken to recover fully. Within the period, the amount of antibody in the blood is at a maximum.

“This finding is valuable because it comes from a real patient who had the virus. And the discovery of this new target means that more effective combination therapies which attack the virus at different points are now possible,” Professor Dave Stuart, Professor of Structural Biology at the University of Oxford, was quoted saying. “Increasing the number of target sites that can be blocked on SARS-CoV-2 also means there is a lower probability that mutations preventing the antibody binding will compromise treatments. Even if one binding site mutates and can no longer be neutralized, the second binding site can still prevent infection,” he added.

One of the major concerns about the antibody therapy is that if it is used more rigorously, it might lead to a mutation of the virus, thus rendering the therapy useless. The new research found that the target site of the virus is highly conserved. It means that the amino acid sequence of the proteins present in the target site are same for almost all the viruses sequenced as of now. The highly conserved site means that different mutated forms of the virus do not want a change in it and it is highly possible that a change in this site would negatively impact the virus. The EY6A antibody can bind to this site and neutralise it, thus becoming a very suitable and safe candidate for antibody therapy.

The antibody therapy needs more randomised control trials to decide on its efficacy and the research might prove to be significant.