Around one in five infected people do not develop antibodies to COVID-19, according to a new study.
Researchers from MedUni Vienna, Austria, also pinpointed one of the reasons why immunity fails to occur.
Dr Rudolf Valenta and his team discovered that the immunity that prevents the virus from docking and invading the body’s cells only occurs when certain antibodies are made.
These specific antibodies must act against the folded receptor binding domain of COVID-19’s spike protein.
The researchers explain that this docking site does not change significantly in different mutations of the virus. But some people cannot produce the correct antibodies.
For this reason, an antigen-based vaccine that targets the receptor binding domain could provide a solution. Their work was published recently in Allergy.
It used microarray technology to examine viral antigens, expecting to see an immune response to protein fragments of these antigens.
They observed that antibodies are exclusively formed against the 3D folded spike protein on COVID-19.
"It now appears that the SARS-CoV-2 virus needs the three-dimensionally folded protein to dock onto the body’s cells," they report. "Only an antibody response against the folded protein, but not against parts of it, protects against infection."
They also showed that only the folded receptor binding domain can generate an immune protection from immunisation, so "vaccination breakthroughs" may be due to a failure to develop antibodies against folded receptor binding domains.
Dr Valenta said: "We urgently need to develop a receptor binding domain-based antigen vaccine which is engineered to overcome the receptor binding domain non-responsiveness."
Gattinger, P. et al. Neutralization of SARS-CoV-2 requires antibodies against conformational receptor-binding domain epitopes. Allergy 28 August 2021; doi: 10.1111/all.15066
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