The antibody recognizes a particular 3D shape on the virus, called an epitope. There is a chance that a similar shape exists in humans, and using this antibody

The antibody recognizes a particular 3D shape on the virus, called an epitope. There is a chance that a similar shape exists in humans, and using this antibody would cause your immune system to attack itself. https://en.wikipedia.org/wiki/Molecular_mimicry https://en.wikipedia.org/wiki/Molecular_mimicry