New study shows how SARS-CoV-2 mutations, if they become widespread, could impact immunological efficacy
In pathology, mutations are double-edged swords. A pathogen can mutate to adapt to the host’s body, or it can mutate for the worse. Indeed, often, the host also mutates in response to a pathogen, and this can go either way too. SARS-CoV-2 carries the potential to mutate in ways that could render a large part of the body’s immunological response ineffective.
A study published in the pre-print server bioRxiv details laboratory experiments at the Rockefeller University in New York that found that viruses engineered to produce the SARS-CoV-2’s spike protein, which helps the pathogen infect cells, developed mutations that changed the spike protein in a way that allows it to evade neutralising antibodies. Similar mutations have been reported in patient samples from around the world, though these make for a minuscule fraction of the genomic variants being reported.
Though the degree to which SARS-CoV-2 will mutate to sidestep neutralising antibodies is not clear, there is no doubt that the mutations being reported could have major implications for antibody action from prior infection, from vaccination and even from passive antibody therapies like convalescent plasma therapy and monoclonal antibodies, which are counted among the most effective measures at the moment.
The emergence of an antibody-resistant strain of the virus—though how likely this remains a matter of speculation at present—will throw a spanner in the global efforts to beat the pandemic. While there are instances reported of patients developing neutralising antibodies in a large number, there are also reports of people who don’t develop antibodies at that scale.
The latter phenomenon could mean that natural SARS-CoV-2 infections, for some reason, fail to elicit B-cell expansion and maturation in some cases; this could mean, experts believe, that with exposure to sub-optimal levels of antibodies during natural infection or during treatment with convalescent plasma with unknown levels of neutralising antibodies, the conditions are ripe for antibody resistance to emerge. The authors of the study recommend the use of combinations of monoclonal antibodies that target different locations on the virus’s receptor-binding site so that overlapping mutations are checkmated.